1. What were the three aspects of the assignments I've submitted that I am most proud of?
-> The lab project. I really like a few of my pictures that I took.
-> The embryonic and fetal development lab.
-> My compendiums
2. What two aspects of my submitted assignments do I believe could have used some improvement?
-> The only one I have for this unit is I'm not that crazy about my essay.
3. What do I believe my overall grade should be for this unit?
-> A
4. How could I perform better in the next unit?
-> Hip, hip, hooray, this is the last unit! :)
Friday, July 18, 2008
Unit 4 Ethical Essay: World Resource Use
You and Me
Energy consumption, population growth, conservation, recycling. They are all such complex topics. How do we best help ourselves and our precious land. What do we do now so that we do not leave our descendents with an unfixable situation. It seems many of the solutions that are discovered to help us conserve our resources are later found to be damaging in a way that was at first not considered. Take, for instance, the practice of recycling. I know that I feel good when I recycle. I know that I am reducing the amount of material that will be dumped in the local landfill. But do my actions result in a net benefit for the environment? I do not have recycling pick up at my house. I have to drive to Sun Dog Ranch Road to drop it off. From there, I'm sure some big diesel burning garbage truck delivers all of the recyclables to processing plant. How far does that truck have to travel beforing reaching the processing plant? Do some goods get delivered to one plant and the others to a different plant? How much energy and other valuable resources do the processing plants have to expend to break my recyclables down into a reusable form? I don't know the answers to these questions, but I do wonder, do we end up with a net benefit or not? Again, these are hugely complex topics with no simple solutions.
Recycling is big here in the US and hopefully in all of the other developed countries of the world. Do they have recycling progroms in 3rd world countries? I am sure they do not. They also do not have individually packaged granola bars and disposable toilet bowl brushes. So the problems that we face today must vary by region and country. The US and other industrialized countries have focused on reducing population growth to a sustainable level. 3rd world countries have not. Should they? Absolutely. Although energy consumption per person is so much less in those countries, so is their supply of naturaly resources. In addition, progress towards leveling off the population growth there needs to start now. We all need to do our part.
More importantly, the industrialized countries of the world need to stay focused on reducing energy consumption and finding renewable sources of energy. Subjects like these can at times feel like they are far off in the distance. They can be topics we do not need to worry about today or that we leave for someone else to worry
about. I, personally, am probably not going to solve the world's energy crisis. So why do I need to think about it. The reason is simple. We all can do our part. We can all turn our air conditioner up a degree or two and our heater down a few degrees. We can all change out our incandescent light bulbs to compact fluorescents. Some of us can ride our bikes to school or work instead of driving our cars. We can choose paperless billing and e-statements instead of receiving paper copies every month. Ways in which each and every one of us can contribute are out there, we just need to put them into practice.
Energy consumption, population growth, conservation, recycling. They are all such complex topics. How do we best help ourselves and our precious land. What do we do now so that we do not leave our descendents with an unfixable situation. It seems many of the solutions that are discovered to help us conserve our resources are later found to be damaging in a way that was at first not considered. Take, for instance, the practice of recycling. I know that I feel good when I recycle. I know that I am reducing the amount of material that will be dumped in the local landfill. But do my actions result in a net benefit for the environment? I do not have recycling pick up at my house. I have to drive to Sun Dog Ranch Road to drop it off. From there, I'm sure some big diesel burning garbage truck delivers all of the recyclables to processing plant. How far does that truck have to travel beforing reaching the processing plant? Do some goods get delivered to one plant and the others to a different plant? How much energy and other valuable resources do the processing plants have to expend to break my recyclables down into a reusable form? I don't know the answers to these questions, but I do wonder, do we end up with a net benefit or not? Again, these are hugely complex topics with no simple solutions.
Recycling is big here in the US and hopefully in all of the other developed countries of the world. Do they have recycling progroms in 3rd world countries? I am sure they do not. They also do not have individually packaged granola bars and disposable toilet bowl brushes. So the problems that we face today must vary by region and country. The US and other industrialized countries have focused on reducing population growth to a sustainable level. 3rd world countries have not. Should they? Absolutely. Although energy consumption per person is so much less in those countries, so is their supply of naturaly resources. In addition, progress towards leveling off the population growth there needs to start now. We all need to do our part.
More importantly, the industrialized countries of the world need to stay focused on reducing energy consumption and finding renewable sources of energy. Subjects like these can at times feel like they are far off in the distance. They can be topics we do not need to worry about today or that we leave for someone else to worry
about. I, personally, am probably not going to solve the world's energy crisis. So why do I need to think about it. The reason is simple. We all can do our part. We can all turn our air conditioner up a degree or two and our heater down a few degrees. We can all change out our incandescent light bulbs to compact fluorescents. Some of us can ride our bikes to school or work instead of driving our cars. We can choose paperless billing and e-statements instead of receiving paper copies every month. Ways in which each and every one of us can contribute are out there, we just need to put them into practice.
Sunday, July 13, 2008
Unit 4 Lab Project: List of Species
one
Scientific name: Prunus avium
Common name: Bing cherry
Interaction: Symbiotic. Provide food to humans. Humans provide CO2, farmers nurture and multiply the species.
Domesticated: Yes. Farmers raise cherry trees.
Future: Symbiotic relationship will hopefully continue! I love cherries.
Scientific name: Prunus avium
Common name: Bing cherry
Interaction: Symbiotic. Provide food to humans. Humans provide CO2, farmers nurture and multiply the species.
Domesticated: Yes. Farmers raise cherry trees.
Future: Symbiotic relationship will hopefully continue! I love cherries.
two
Scientific name: Canis familiaris
Common name: Beagle
Interaction: Symbiotic. Humans breed and care for beagles...house them, feed them. Beagles are watchdogs (in terms of altering owners to potential invaders) and great companions.
Domesticated: Yes.
Future: Symbiotic relationship will continue.
three
Scientific name: Acer griseum
Common name: Paperbark maple
Interaction: Symbiotic. Humans provide CO2, plant and nurture. Provide oxygen, shade, beauty, enjoyment to humans.
Domesticated: Yes. Farmers raise these trees to sell for others to plant and nurture.
Future: Symbiotic relationship will continue.
four
Scientific name: Zinnia sp.
Common name: Zinnia
Interaction: Symbiotic. Humans plant and care for. Zinnias provide beauty, enjoyment.
Domesticated: Yes. Farmers raise zinnias to sell.
Future: Symbiotic relationship will continue.
five
Scientific name: Taxodium distichum
Common name: Bald cypress
Interaction: Symbiotic. Humans provide CO2 and care for trees. Bald cypress provides oxygen, shade, beauty, enjoyment
Domesticated: Yes.
Future: Symbiotic relationship will continue.
six
Scientific name: Clupea harengus
Common name: Sardines.
Interaction: Predation. I have tried to think of a way that humans are of some benefit to herring, but I have not been able to come up with any!
Domesticated: No.
Future: Predation will continue. Humans will continue to hunt and eat herring.
seven
Scientific name: Scolopendra heros
Common name: Giant desert centipede
Interaction: Commensal/symbiotic. They benefit humans by eating cockroaches. The thought is revolting to me, but some people may keep them as pets!!!
Domesticated: No.
Future: I think the relationshiop will remain mostly commensal.
eight
Scientific name: Sylvilagus floridanus
Common name: Eastern cottontail
Interaction: Symbiotic. Unfortunately, humans provide tasty vegetation for rabbits. Some humans eat rabbits.
Domesticated: Yes, some species.
Future: Symbiotic relationship will continue.
nine
Scientific name: Casmerodius albus
Common name: Great egret
Interaction: Symbiotic...maybe mutualistic. Humans provide retention ponds as a habitat for the egret. The bird provides beauty and enjoyment.
Domesticated: No.
Future: Symbiotic/mutualistic relationship will continue.
ten
Scientific name: Acer palmatum atropurpureum
Common name: Red Japanese Maple
Interaction: Symbiotic. Provide oxygen, beauty, enjoyment to humans. Humans provide CO2, plant and care for.
Domesticated: Yes. Humans must nurture them.
Future: Symbiotic relationship will continue.
eleven
Scientific name: Fagus sylvatica 'Tricolor'
Common name: Tricolor European Beech
Interaction: Symbiotic. Provides oxygen, beauty, enjoyment to humans. Humans multiply and care for.
Domesticated: Yes. See above.
Future: Symbiotic relationship will continue.
twelve
Scientific name: Lycopersicon esculentum L
Common name: Tomato
Interaction: Symbiotic. Tomatoes provide food, humans raise and care for the plants.
Domesticated: Yes. Farmers raise them.
Future: Symbiotic relationship will continue.
thirteen
Scientific name: Zea mays
Common name: Sweet corn
Interaction: Symbiotic. Sweet corn provides food for humans. Humans plant corn like crazy.
Domesticated: Yes. Farmers raise corn.
Future: Symbiotic relationship will continue.
fourteen
Scientific name: Malus domestica Borkh
Common name: Braeburn apple
Interaction: Symbiotic. Apple tree provides food to humans. Humans plant and nurture the trees.
Domesticated: Yes. Farmers raise apple trees.
Future: Symbiotic relationship will continue.
fifteen
Scientific name: Vaccinium corymbosum
Common name: Blueberry
Interaction: Symbiotic. Bush provides delicious fruit to humans. Humans plant and care for the plant.
Domesticated: Yes. Farmers raise blueberry bushes.
Future: Symbiotic relationship will continue.
sixteen
Scientific name: Asparagus officinalis
Common name: Garden asparagus
Interaction: Symbiotic. Asparagus is food for humans and humans plant it.
Domesticated: Yes.
Future: Symbiotic relationship will continue.
seventeen
Scientific name: Fragaria ananassa
Common name: Strawberry
Interaction: Symbiotic. Strawberry is a tasty food for humans. Humans plant the strawberry bush.
Domesticated: Yes.
Future: Symbiotic relationship will continue.
eighteen
Scientific name: Lactuca sativa
Common name: Leaf lettuce
Interaction: Symbiotic. Lettuce is a food source for humans. Humans plant many seeds a year to grow lettuce.
Domesticated: Yes. Farmers raise lettuce.
Future: Symbiotic relationship will continue.
nineteen
Scientific name: Arachis hypogaea L.
Common name: Peanut
Interaction: Symbiotic.
Domesticated: Yes. Farmers raise peanut plants.
Future: Symbiotic relationship will continue.
twenty
Scientific name: Achillea millefolium
Common name: Yarrow
Interaction: Symbiotic. Yarrow provide beauty and oxygen to humans. Humans plant and nurture yarrow.
Domesticated: Yes. Farmers raise yarrow to sell to others.
Future: Symbiotic relationship will continue.
Unit 4, Online Lab #2: Demographics
SIMULATION SCREEN SHOTS
World and low fertility rate (Greece):
World and high fertility rate (Zaire):
QUESTIONS AND ANSWERS
1. What was your high fertility rate country and what was its fertility rate?
-> The high fertility rate country that I chose was Zaire. Its fertility rate was 6.10.
2. What was your low fertility rate country and what was its fertility rate?
-> The low fertility rate country that I chose was Greece. Its fertility rate was 1.50.
3. The initial demographic "shape" of your high fertility rate country should have been a pyramid, with high population in young age groups. Explain why high fertility rate results in a high percentage of young people in the population. How does this affect future population growth?
-> A high fertility rate means that on average couples are having more than 2 kids. By having more than 2 kids, each couple is increasing the size of the next generation. This means there will be a higher percentage of young people compared to the previous generation. As those kids reach reproductive age, there will be more people at that stage compared to the amount there were at that stage in the previous generation. If the fertility rate is still high, that generation will produce more individuals than they have in there own. In this way, a high fertility rate has an impact on future growth.
4. Your low fertility rate country might have had a more oval-shaped curve with high population in middle age groups. This is especially exaggerated if the fertility rate is below 2.00. Explain why low fertility rate leads to lots of middle-aged people.
-> If the reproductive age group has less on average than 2 kids per couple, they are going to leave the next generation with few people than they have. If this trend continues, the middle aged group will always be larger than the younger generations.
5. Write ten adjectives or descriptive phrases for what you might expect life, people's attitudes, conditions on the streets, etc. will be like in each of those situations. Imagine a situation with lots of middle-aged and older people in the population and write ten quick "brain-storm" descriptors for you think it would be like (Prescott, Arizona?). Then do the same for a situation with lots of children in the population.
Lots of middle age/older: working, traveling, comfortable, expendable income, free time, health care, health check ups, nursing homes, hip replacements, obituaries
Lots of children: daycare, poor, one income families, schools, errands, sharing ideas, screaming, playing, giving, hungry
World and low fertility rate (Greece):
World and high fertility rate (Zaire):
QUESTIONS AND ANSWERS
1. What was your high fertility rate country and what was its fertility rate?
-> The high fertility rate country that I chose was Zaire. Its fertility rate was 6.10.
2. What was your low fertility rate country and what was its fertility rate?
-> The low fertility rate country that I chose was Greece. Its fertility rate was 1.50.
3. The initial demographic "shape" of your high fertility rate country should have been a pyramid, with high population in young age groups. Explain why high fertility rate results in a high percentage of young people in the population. How does this affect future population growth?
-> A high fertility rate means that on average couples are having more than 2 kids. By having more than 2 kids, each couple is increasing the size of the next generation. This means there will be a higher percentage of young people compared to the previous generation. As those kids reach reproductive age, there will be more people at that stage compared to the amount there were at that stage in the previous generation. If the fertility rate is still high, that generation will produce more individuals than they have in there own. In this way, a high fertility rate has an impact on future growth.
4. Your low fertility rate country might have had a more oval-shaped curve with high population in middle age groups. This is especially exaggerated if the fertility rate is below 2.00. Explain why low fertility rate leads to lots of middle-aged people.
-> If the reproductive age group has less on average than 2 kids per couple, they are going to leave the next generation with few people than they have. If this trend continues, the middle aged group will always be larger than the younger generations.
5. Write ten adjectives or descriptive phrases for what you might expect life, people's attitudes, conditions on the streets, etc. will be like in each of those situations. Imagine a situation with lots of middle-aged and older people in the population and write ten quick "brain-storm" descriptors for you think it would be like (Prescott, Arizona?). Then do the same for a situation with lots of children in the population.
Lots of middle age/older: working, traveling, comfortable, expendable income, free time, health care, health check ups, nursing homes, hip replacements, obituaries
Lots of children: daycare, poor, one income families, schools, errands, sharing ideas, screaming, playing, giving, hungry
Compendium Review Unit 4 Major Topic: Human Landscapes
I. Human Evolution
A. Origin of Life
B. Biological Evolution
C. Classification of Humans
D. Evolution of Hominids
E. Evolution of Humans
II. Global Ecology and Human Interferences
A. The Nature of Ecosystems
B. Energy Flow
C. Global Biogeochemical Cycles
III. Human Population, Planetary Resources, and Conservation
A. Human Population Growth
B. Human Use of Resources and Pollution
C. Biodiversity
D. Working Towards a Sustainable Society
I. Human Evolution
A. Origin of Life chemical evolution
1. The primitive Earth
a. early Earth's atmosphere different than today's
b. atmosphere formed by gases escaping from volcanoes
c. atmosphere made up of H2O, N2, CO2, small amounts of H2, CO
d. water only existed as gas until Earth cooled, it rained forming oceans
2. Small organic molecules
a. rain washed gases into oceans
b. many sources of energy: volcanoes, meteorites, radioactive isotopes, lightning, ultraviolet radiation
c. energy + primitive gases react to produce small organic cmpds = nucleotides, amino acids (demonstrated in closed sys by Stanley Miller 1953)
3. Macromolecules new small organic molecules joined=macromolecules
a. RNA-first hypothesis - RNA as substrate and enzyme
b. protein-first hypothesis - amino acids joined to form microspheres
4. The protocell
a. microsphere + lipids = lipid-protein membrane
b. formation of protocell, probably a heterotroph & fermenter
5. The true cell
a. RNA-first hypothesis - genes of RNA specified protein synthesis (enzymes), enzymes used RNA to form DNA
b. protein-first hypothesis - proteins evolved enzymatic ability to synthesize DNA from nucleotides in ocean, DNA then specifies protein synthesis
Figure 22.1 illustrates chemical evolution.
The following table from Professor Frolich's presentation lists some of the major events in Earth's history.
B. Biological Evolution
1. Common descent
a. Charles Darwin - naturalist - theory of evolution
b. fossil evidence supports evolution
i. examples: traces - trails, footprints, burrows, worm casts, droppings; fossils - bone, impressions of plants, insects trapped in amber
ii. sediment -> strata - allows dating of fossils
iii. fossil record - most direct evidence that evolution has occurred, shows life has progressed from simple to complex (prokaryote->eukaryote->multicellular organism
c. biogeographical evidence - migration of ancestral species to isolated geographies allows evolution into different species
d. anatomical evidence - common descent hypothesis explains anatomical similarities among organisms of different species, despite functional differences
i. homologous structures - evidence of relatedness between organisms
ii. analogous structures
iii. vestigal structures - more evidence of common descent
iv. similarities in embryological development - eg paired pharyngeal pouches, postanal tail
Figure 22.6 from the text shows homologous structures.
e. biochemical evidence - same basic biochem molecules across almost all living organisms: DNA, ATP, enzymes, same triplet code in DNA, same 20 amino acids
2. Intelligent design
a. idea that diversity of life had to arise from the involvement of an "intelligent agent"
b. can not be tested in a scientific way
3. Natural selection - Darwin
a. described a mechanism for adaptation
b. variation - physical characteristics passed down to next generation
c. competition for limited resources - because of limited resources, not all individuals in a population survive
d. adaptation - those characteristics that give advantage to secure resources will be passed down to next generation. Over time, environment selects for the better-adapted traits
e. accounts for great diversity in life
Figure 22.9 from the text contrasts Jean-Baptiste Lamarck's process of acquired characteristics with Charles Darwin's process of natural selection.
C. Classification of humans
1. DNA data and human evolution
a. DNA/rRNA/protein sequencing data used compare and determine relatedness between species
2. Humans are primates adapted to arboreal life
a. mobile forelimbs and hindlimbs - easy grasping
b. binocular vision - accurate focusing
c. large, complex brain - sight, good hand-eye coordination
d. reduced reproductive rate - 1 birth at a time, extended junvenile dependency, learned behaviors, complex social interactions
3. Comparing human skeleton to the chimpanzee skeleton
a. human-spine exits center of skull-places skull in midline of body, chimpanzee-spine exits rear of skull
b. human spine s-shaped-trunk's center of gravity squarely over feet, chimp spine-slight curve
c. human pelvis & hip joint broader-no swaying when walking, chimp-narrow
d. human neck of femur longer-femur angles in at knees, chimp-femur angles out
e. human knee joint larger-supports body weight, chimp-smaller
f. human big toe not opposable, foot has arch-allows long walking and running, chimp opposable toe
D. Evolution of Hominids
1. The first hominids
a. first hominids and apes divereged from common ancestor - at time of divergence, genes and proteins of two lineages very similar
2. Hominid features
a. bipedal posture
b. shape of face- flatter face, more pronounced chin - human jaw shorter, smaller, l
i. flatter face, more pronounced chin b/c human jaw is shorter
ii. smaller, less specialized teetch
iii. larger brain
Figure 22.13 from the text shows the evolution of primates
3. Earliest fossil hominids
a. fossils found that date back to the time of ape and human lineage split
b. date between 7mya and 5mya
4. Evolution of autralopithecines
a. marks the earnest beginning of the hominid line of descent
b. gracile (slender) and robust (powerful) types
Figure 22.14 from the text shows a reconstruction of Lucy, the australopithecine, and footprints of A. afarensis.
5. Southern Africa
a. Australopithecus africanus - gracile type dated 2.8 mya
b. A. robustus - 2 to 1.5 mya
c. both walked upright, limb proportions apelike
6. Eastern Africa
a. 250 fossils of hominid A. afarensis - Lucy - found by Donald Johanson
b. walked bipedally
c. example of mosaic evolution (small apelike brain with bipedal ability)
E. Evolution of Humans
1. Early Homo
a. Homo habilis - 2.0-1.9mya, omnivores, used tools, cooperative hunting, hunters and gatherers shared food
b. Homo erectus (Asian form?)
i. larger brain, flatter face, nose projected - compared to H. habilis
ii. Homo ergaster (African form) - taller, robust, heavily musculed skeleton, small birth canal
iii. first to use fire, more advanced tools
Figure 22.15 from the text shows human evolution.
Figure 22.16 from the text show the skeleton of a 10 year old boy of the species Homo ergaster.
2. Evolution of modern humans
a. multiregional continuity hypothesis
b. out-of-Africa hypothesis
3. Neandertals 200,000 years BP
a. massive brow ridge, nose, jaw, teeth protruded, low & sloping forehead, lower jaw lacked a chin
b. brain larger than Homo sapien's, maybe to control extra musculature
c. culturally advanced - built houses, used many tools & fire, buried dead
Figure 22.18 from the text illustrates how Neandertals may have looked and lived.
4. Cro-Magnons
a. oldest fossils to be designated Homo sapiens
b. entered Asia and Europe from Africa 100,000 yrs BP
c. DNA very different from Neandertal DNA - Neandertals probably cousins to Homo sapiens
d. made advanced tools (compound), experienced hunters may have caused extinction of larger animals
e. hunted cooperatively, women remained home with children
f. first to have language
g. culture included art
Figure 22.19 from the text illustrates the Cro-Magnons.
5. Human variation
a. humans geographically distributed
b. body shape and environment
i. cold temps - short limbs (Allen's rule), bulkier build (Bergmann's rule)
ii. warm temps - elongated limbs, slighter build
c. genetic evidence for a common ancestry
i. genetic differences in mDNA between different ethnic groups low - support out-of-Africa hypothesis
Definitions from Chapter 22 can be found here.
II. Global Ecology and Human Interferences
A. The Nature of Ecosystems
1. Ecosystems
a. tropical rain forest - at equator, large evergreen, broad-leaved tree
b. savanna - tropical grassland supports grazing animals
c. temperate grasslands (less rain than) temperate forests (trees lose leaves during winter)
d. desert - little water, no trees
e. taiga - very cold, norther coniferous forest
f. tundra - borders North Pole, very cold, long winters, permafrost
g. freshwater aquatic ecosystem - standing water (lakes, ponds), running water (rivers, streams), marshes where rivers meet sea
h. saltwater aquatic ecosystem - oceans, have coral reefs
Figure 23.1 from the text show the major terrestrial ecosystems.
Figure 23.2 from the text shows the major aquatic ecosystems.
2. Biotic components of an ecosystem
a. autotrophs (producers)-use inorganic nutrients plus energy source to produce organic nutrients, for self & for other members of community. Algae & plants
b. hetertroph (consumers) - need a source of organic nutrients
i. herbivores
ii. carnivores - primary, secondary, tertiary consumers
iii. omnivores
iv. detritus feeders - feed on detritus (decomposing particles of organic matter), break down dead organic matter & release inorganic substances that are taken up by plants. eg: earthworms, termites, ants, bacteria, fungi
Figure 23.3 shows some examples of bitotic components.
3. Energy flow and chemical cycling
a. most ecosystems require continual supply of energy from the sun
b. as organic nutrients are passed up the food chain, a smaller percentage of nutrients is available to higher-levels>
Figure 23.4 from the text illustrates energy flow and chemical cycling.
B. Energy Flow
1. Trophic levels
a. trees - producers - first trophic level
b. first series of animals eating trees - primary consumers - second trophic level
c. next group of animals - secondary consumers - third trophic level
2. Ecological pyramids
a. illustrates loss of 90% of energy between trophic levels.
b. therefore, few carnivores can be supported in food web
C. Global Biogeochemical Cycles
1. The water cycle
a. evaporation, precipitation, transpiration, gravity=water returns to sea, runoff, aquifers
b. human activities
i. withdraw water from aquifers
ii. clear vegetation from land, build roads, building - prevent percolation and increase runoff
iii. interfere with natural processes that purify water, add pollutants
Figure 23.9 from the test illustrates the hydrologic cycle.
2. The carbon cycle
a. CO2 in atmosphere is exchange pool for carbon cycle
b. plants take up CO2 - thru photosynthesis incorporate carbon into nutrients
c. carbon is returned to atmosphere as CO2 through respiration by organisms
d. CO2 in air combines with H2O to produce HCO3 bicarbonate ion. Source of carbon for algae
e. CO2 given off by aquatic organisms becomes bicarbonate ions
f. reservoirs for carbon=living & dead organisms, fossil fuels
g. human interference = burning of fossil fuels, destruction of forests puts more CO2 into atmosphere than is being used up
h. greenhouse gases allow solar radiation to pass thru but hinder the escape of infrared rays back into space
Figure 23.10 from the text illustrates the carbon cycle.
3. The nitrogen cycle
a. nitrogen fixation - N2->NH4 (form of nitrogen plants can use, by cyanobacteria and free-living bacteria in soil
b. nitrification - N2->NO3, needs high energy source, NH4->N02 by by soil bacteria, NO2->NO3
c. assimilation
d. denitrification
e. human interferences - N2 fertilizers, runoff causes overgrowth of algae, rooted aquatic plants.
f. acid deposition from burning fossil fuels: nitrogen oxides and sulfur dioxide enter atmosphere, combine w/water vapor to form acids
g. smog - nigrogen oxides and hydrocarbons combined
Figure 23.12 from the text illustrates the nitrogen cycle
4. The phosphorus cycle
a. phosphorus trapped in sediments moves to land after geological movement
b. weathering of rocks places phosphate ions into soil
c. plants use some (phospholipids, ATP, nucleotides)
d. animals eat producers, incorporate phosphate into teeth, bones, shells
e. death and decay make phosphate ions available to producers again
f. phosphate runoff into aquatic ecosystems, algae acquire some
g. humans boost supply by mining, runoff from fertilizer, animal waste, sewage planst results in cultural eutrophication of waterways
Figure 23.15 from the text illustrates the phosphorus cycle.
Figure 23.16 lists sources of surface water pollution.
Definitions for Chapter 23 can be found here.
III. Human Population, Planetary Resources, and Conservation
A. Human Population Growth
1. The MDCs - more developed countries
a. growth rate as a whole .1%, down from 1850-1950 when the population doubled
b. US growth rate .6%, immigrants, baby boom
c. total population expected to be at 1.2 billion by 2050
2. The LDCs - less-developed countries
a. growth rate at 1.6%
b. by 2050, population expected to jump from 5 to 8 billion
2. Comparing age structure
a. 3 age groups: prereproductive, reproductive, postreproductive
b. LDCs growth will continue, more young women in reproductive years
c. other than the US, MDCs have a stabilized age-structure diagram
Figure 24.1 from the text shows the human population growth.
Figure 24.2 shows the age-structure diagrams for MDCs and LDCs.
B. Human Use of Resources and Pollution
1. Land
a. beaches and human habitation - people like to live near the coastline - a place for fish spawning, habitats for terrestrial species, protection for coastal areas during storms
b. semiarid lakes and human habitation - humans allow animals to overgraze, they clear the land, use for fuel, fodder, water then runs off instead of being aborbed by remaining plants or replenishing wells, land becomes lifeless desert=desertification
c. tropical rain forest and human habitation - deforestation in tropical rain forests can cause desertification, loss of biodiversity
2. Water
a. increasing water supplies
i. dams - provide water, electricity. Rivers not making it to oceans, water loss to evaporation & seepage to rock beds, increase salinity, silt buildup
ii. aquifers - rain collected over hundreds of thousands of years ago, resource depletion - causes subsidence, sinkholes, saltwater intrusion
b. conservation of water - drought, salt-tolerant crops, drip irrigation, industries adopting conservation measures
3. Food food supply has increased since the 50s
a. modern/harmful farming methods - monoculture, fertilizers (production energy intensive, water pollution, kills good soil bacteria), irrigation, fuel consumption
b. positive practices - polyculture, contour farming, no-till
c. soil loss and degradation - erosion of topsoil (richest soil), sediment ends up in lakes and streams
d. green revolutions - varieties developed to yield more for in LDCs required same amount of fertizlier, water, pesticides, genetic engineering
e. domestic livestock - accounts for much pollution associated w/farming. 2/3 of cropland in US devoted to grow feed livestock. Much energy required to make food to feed livestock
Figure 24.10 from the text shows several methods of conservation.
4. Energy
a. nonrenewable sources - nuclear power, fossil fuels
b. burning of fossil fuels emites gases - rising temps threaten melting of glaciers, habitats threatened
c. renewable sources - hydropower, geothermal energy, wind power, solar
d. solar-hydrogen - using solar power to extract hyrdogen from water via electrolysis. Hydrogen can then be used as a clean-burning fuel
Figure 24.12 from the text shows 4 types of renewable energy sources.
5. Minerals
a. eg. fossil fuels, nonmetallic raw materials (sand, gravel, phosphate), metals (aluminum, copper, iron, lead, gold)
b. harmful to humans - heavy metals: lead, mercury, arsenic, cadmium, tin, chromium, zinc, and copper. Used to make batteries, electronics, pesticides, medicines, paints, inks, dyes
c. hazardous wastes - contributed by the consumption of minerals
d. 4 most common heavy metal contaminants - lead, arsenic, cadmium, chromium
e. 5 most common synthetic organic cmpds - trichloroethylene, toluene, benzene, polychlorinated biphenyls (PCBs), and cloroform.
f. synthetic organic chemicals - halogentaed hydrocarbons, used in production of plastics, pesticides, cosmetics, coatings, solvents...Chlorofluorocarbons (CFCs) - thinning of Earth's ozone. MDCs no longer use.
C. Biodiversity
1. Loss of biodiversity
a. habitat loss due to human interference
b. alien species
c. pollution - acid deposition, global warming, ozone depletion, synthetic organic chemicals
d. overexploitation
e. disease
2. Direct value of biodiversity
a. medicinal value - rosy periwinkle, penicillin, limulus in blood of horseshoe crab
b. agricultural value - natural predators, pollinators
c. consumptive use value - aquatic organisms, wild fruits, vegetables, trees
3. Indirect value of biodiversity
a. waste disposal - decomposers extremely useful to humans
b. provision of freshwater - after a storm forests soak up water and then release over a long period of time, preventing flooding
c. prevention of soil erosion - deforestation causes erosion, erosion causes silt buildup in dams and ecosystems
d. biogeochmeical cycles - keeps excess pollutants in environment under control
e. regulation of climate - trees provide shade, take up CO2, when cut, they release CO2, contributing to global warming
f. ecotourism
Figure 24.17 from the text provide examples of the direct benefits of wildlife.
D. Working Toward a Sustainable Society
1. Today's sustainable society
a. overpopulation of LDCs and overconsumption by MDCs both account for increasing poullution and extinction of wildlife
b. land used for human purposes
c. agriculture - big use of fossil fuels, use of pesticides, create pollution, use of freshwater
d. demand on freshwater
e. growing demand on energy sources
2. Characteristics of a sustainable society
a. use renewable energy
b. recycle materials
c. protect natural ecosystems
d. efficiency
e. rural sustainability - preserve ecosystems, cover crops, multiuse farming, composting, low flow or trickle irrigation, cultivars, precision farming, integrated pest management, plant variety of species, multipurpose trees, protect wetlands, buy local
f. urban sustainability - energy efficient transportation sys, solar/geothermal energy, green roofs, improve storm water mgmt, plant native grasses, greenbelts, revitalize old sections before developing new, control light and noise pollution, encourage recycling
3. Assessing economic well-being and quality of life
a. GNP - strictly economic
b. ISEW (index of sustainable economic welfare) - takes into account forms of value in addition to monetary value (environmental damage, natural resource depletion, distributional equite etc)
c. GPI (genuine progress indicator) - considers quality of life
d. use value, option value, existence value, aesthetic value, cultural value, scientific & educational value
Figure 24.18 from the text shows several unsustainable activities.
Definitions from Chapter 24 can be found here.
REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).
Links provided throughout the summary take you to online sources.
IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).
A. Origin of Life
B. Biological Evolution
C. Classification of Humans
D. Evolution of Hominids
E. Evolution of Humans
II. Global Ecology and Human Interferences
A. The Nature of Ecosystems
B. Energy Flow
C. Global Biogeochemical Cycles
III. Human Population, Planetary Resources, and Conservation
A. Human Population Growth
B. Human Use of Resources and Pollution
C. Biodiversity
D. Working Towards a Sustainable Society
I. Human Evolution
A. Origin of Life chemical evolution
1. The primitive Earth
a. early Earth's atmosphere different than today's
b. atmosphere formed by gases escaping from volcanoes
c. atmosphere made up of H2O, N2, CO2, small amounts of H2, CO
d. water only existed as gas until Earth cooled, it rained forming oceans
2. Small organic molecules
a. rain washed gases into oceans
b. many sources of energy: volcanoes, meteorites, radioactive isotopes, lightning, ultraviolet radiation
c. energy + primitive gases react to produce small organic cmpds = nucleotides, amino acids (demonstrated in closed sys by Stanley Miller 1953)
3. Macromolecules new small organic molecules joined=macromolecules
a. RNA-first hypothesis - RNA as substrate and enzyme
b. protein-first hypothesis - amino acids joined to form microspheres
4. The protocell
a. microsphere + lipids = lipid-protein membrane
b. formation of protocell, probably a heterotroph & fermenter
5. The true cell
a. RNA-first hypothesis - genes of RNA specified protein synthesis (enzymes), enzymes used RNA to form DNA
b. protein-first hypothesis - proteins evolved enzymatic ability to synthesize DNA from nucleotides in ocean, DNA then specifies protein synthesis
Figure 22.1 illustrates chemical evolution.
The following table from Professor Frolich's presentation lists some of the major events in Earth's history.
B. Biological Evolution1. Common descent
a. Charles Darwin - naturalist - theory of evolution
b. fossil evidence supports evolution
i. examples: traces - trails, footprints, burrows, worm casts, droppings; fossils - bone, impressions of plants, insects trapped in amber
ii. sediment -> strata - allows dating of fossils
iii. fossil record - most direct evidence that evolution has occurred, shows life has progressed from simple to complex (prokaryote->eukaryote->multicellular organism
c. biogeographical evidence - migration of ancestral species to isolated geographies allows evolution into different species
d. anatomical evidence - common descent hypothesis explains anatomical similarities among organisms of different species, despite functional differences
i. homologous structures - evidence of relatedness between organisms
ii. analogous structures
iii. vestigal structures - more evidence of common descent
iv. similarities in embryological development - eg paired pharyngeal pouches, postanal tail
Figure 22.6 from the text shows homologous structures.
e. biochemical evidence - same basic biochem molecules across almost all living organisms: DNA, ATP, enzymes, same triplet code in DNA, same 20 amino acids
2. Intelligent design
a. idea that diversity of life had to arise from the involvement of an "intelligent agent"
b. can not be tested in a scientific way
3. Natural selection - Darwin
a. described a mechanism for adaptation
b. variation - physical characteristics passed down to next generation
c. competition for limited resources - because of limited resources, not all individuals in a population survive
d. adaptation - those characteristics that give advantage to secure resources will be passed down to next generation. Over time, environment selects for the better-adapted traits
e. accounts for great diversity in life
Figure 22.9 from the text contrasts Jean-Baptiste Lamarck's process of acquired characteristics with Charles Darwin's process of natural selection.
C. Classification of humans
1. DNA data and human evolution
a. DNA/rRNA/protein sequencing data used compare and determine relatedness between species
2. Humans are primates adapted to arboreal life
a. mobile forelimbs and hindlimbs - easy grasping
b. binocular vision - accurate focusing
c. large, complex brain - sight, good hand-eye coordination
d. reduced reproductive rate - 1 birth at a time, extended junvenile dependency, learned behaviors, complex social interactions
3. Comparing human skeleton to the chimpanzee skeleton
a. human-spine exits center of skull-places skull in midline of body, chimpanzee-spine exits rear of skull
b. human spine s-shaped-trunk's center of gravity squarely over feet, chimp spine-slight curve
c. human pelvis & hip joint broader-no swaying when walking, chimp-narrow
d. human neck of femur longer-femur angles in at knees, chimp-femur angles out
e. human knee joint larger-supports body weight, chimp-smaller
f. human big toe not opposable, foot has arch-allows long walking and running, chimp opposable toe
D. Evolution of Hominids
1. The first hominids
a. first hominids and apes divereged from common ancestor - at time of divergence, genes and proteins of two lineages very similar
2. Hominid features
a. bipedal posture
b. shape of face- flatter face, more pronounced chin - human jaw shorter, smaller, l
i. flatter face, more pronounced chin b/c human jaw is shorter
ii. smaller, less specialized teetch
iii. larger brain
Figure 22.13 from the text shows the evolution of primates
3. Earliest fossil hominids
a. fossils found that date back to the time of ape and human lineage split
b. date between 7mya and 5mya
4. Evolution of autralopithecines
a. marks the earnest beginning of the hominid line of descent
b. gracile (slender) and robust (powerful) types
Figure 22.14 from the text shows a reconstruction of Lucy, the australopithecine, and footprints of A. afarensis.
5. Southern Africa
a. Australopithecus africanus - gracile type dated 2.8 mya
b. A. robustus - 2 to 1.5 mya
c. both walked upright, limb proportions apelike
6. Eastern Africa
a. 250 fossils of hominid A. afarensis - Lucy - found by Donald Johanson
b. walked bipedally
c. example of mosaic evolution (small apelike brain with bipedal ability)
E. Evolution of Humans
1. Early Homo
a. Homo habilis - 2.0-1.9mya, omnivores, used tools, cooperative hunting, hunters and gatherers shared food
b. Homo erectus (Asian form?)
i. larger brain, flatter face, nose projected - compared to H. habilis
ii. Homo ergaster (African form) - taller, robust, heavily musculed skeleton, small birth canal
iii. first to use fire, more advanced tools
Figure 22.15 from the text shows human evolution.
Figure 22.16 from the text show the skeleton of a 10 year old boy of the species Homo ergaster.
2. Evolution of modern humansa. multiregional continuity hypothesis
b. out-of-Africa hypothesis
3. Neandertals 200,000 years BP
a. massive brow ridge, nose, jaw, teeth protruded, low & sloping forehead, lower jaw lacked a chin
b. brain larger than Homo sapien's, maybe to control extra musculature
c. culturally advanced - built houses, used many tools & fire, buried dead
Figure 22.18 from the text illustrates how Neandertals may have looked and lived.
4. Cro-Magnons
a. oldest fossils to be designated Homo sapiens
b. entered Asia and Europe from Africa 100,000 yrs BP
c. DNA very different from Neandertal DNA - Neandertals probably cousins to Homo sapiens
d. made advanced tools (compound), experienced hunters may have caused extinction of larger animals
e. hunted cooperatively, women remained home with children
f. first to have language
g. culture included art
Figure 22.19 from the text illustrates the Cro-Magnons.
5. Human variation
a. humans geographically distributed
b. body shape and environment
i. cold temps - short limbs (Allen's rule), bulkier build (Bergmann's rule)
ii. warm temps - elongated limbs, slighter build
c. genetic evidence for a common ancestry
i. genetic differences in mDNA between different ethnic groups low - support out-of-Africa hypothesis
Definitions from Chapter 22 can be found here.
II. Global Ecology and Human Interferences
A. The Nature of Ecosystems
1. Ecosystems
a. tropical rain forest - at equator, large evergreen, broad-leaved tree
b. savanna - tropical grassland supports grazing animals
c. temperate grasslands (less rain than) temperate forests (trees lose leaves during winter)
d. desert - little water, no trees
e. taiga - very cold, norther coniferous forest
f. tundra - borders North Pole, very cold, long winters, permafrost
g. freshwater aquatic ecosystem - standing water (lakes, ponds), running water (rivers, streams), marshes where rivers meet sea
h. saltwater aquatic ecosystem - oceans, have coral reefs
Figure 23.1 from the text show the major terrestrial ecosystems.
Figure 23.2 from the text shows the major aquatic ecosystems.
2. Biotic components of an ecosystem
a. autotrophs (producers)-use inorganic nutrients plus energy source to produce organic nutrients, for self & for other members of community. Algae & plants
b. hetertroph (consumers) - need a source of organic nutrients
i. herbivores
ii. carnivores - primary, secondary, tertiary consumers
iii. omnivores
iv. detritus feeders - feed on detritus (decomposing particles of organic matter), break down dead organic matter & release inorganic substances that are taken up by plants. eg: earthworms, termites, ants, bacteria, fungi
Figure 23.3 shows some examples of bitotic components.
3. Energy flow and chemical cycling
a. most ecosystems require continual supply of energy from the sun
b. as organic nutrients are passed up the food chain, a smaller percentage of nutrients is available to higher-levels>
Figure 23.4 from the text illustrates energy flow and chemical cycling.
B. Energy Flow
1. Trophic levels
a. trees - producers - first trophic level
b. first series of animals eating trees - primary consumers - second trophic level
c. next group of animals - secondary consumers - third trophic level
2. Ecological pyramids
a. illustrates loss of 90% of energy between trophic levels.
b. therefore, few carnivores can be supported in food web
C. Global Biogeochemical Cycles
1. The water cycle
a. evaporation, precipitation, transpiration, gravity=water returns to sea, runoff, aquifers
b. human activities
i. withdraw water from aquifers
ii. clear vegetation from land, build roads, building - prevent percolation and increase runoff
iii. interfere with natural processes that purify water, add pollutants
Figure 23.9 from the test illustrates the hydrologic cycle.
2. The carbon cycle
a. CO2 in atmosphere is exchange pool for carbon cycle
b. plants take up CO2 - thru photosynthesis incorporate carbon into nutrients
c. carbon is returned to atmosphere as CO2 through respiration by organisms
d. CO2 in air combines with H2O to produce HCO3 bicarbonate ion. Source of carbon for algae
e. CO2 given off by aquatic organisms becomes bicarbonate ions
f. reservoirs for carbon=living & dead organisms, fossil fuels
g. human interference = burning of fossil fuels, destruction of forests puts more CO2 into atmosphere than is being used up
h. greenhouse gases allow solar radiation to pass thru but hinder the escape of infrared rays back into space
Figure 23.10 from the text illustrates the carbon cycle.
3. The nitrogen cycle
a. nitrogen fixation - N2->NH4 (form of nitrogen plants can use, by cyanobacteria and free-living bacteria in soil
b. nitrification - N2->NO3, needs high energy source, NH4->N02 by by soil bacteria, NO2->NO3
c. assimilation
d. denitrification
e. human interferences - N2 fertilizers, runoff causes overgrowth of algae, rooted aquatic plants.
f. acid deposition from burning fossil fuels: nitrogen oxides and sulfur dioxide enter atmosphere, combine w/water vapor to form acids
g. smog - nigrogen oxides and hydrocarbons combined
Figure 23.12 from the text illustrates the nitrogen cycle
4. The phosphorus cycle
a. phosphorus trapped in sediments moves to land after geological movement
b. weathering of rocks places phosphate ions into soil
c. plants use some (phospholipids, ATP, nucleotides)
d. animals eat producers, incorporate phosphate into teeth, bones, shells
e. death and decay make phosphate ions available to producers again
f. phosphate runoff into aquatic ecosystems, algae acquire some
g. humans boost supply by mining, runoff from fertilizer, animal waste, sewage planst results in cultural eutrophication of waterways
Figure 23.15 from the text illustrates the phosphorus cycle.
Figure 23.16 lists sources of surface water pollution.
Definitions for Chapter 23 can be found here.
III. Human Population, Planetary Resources, and Conservation
A. Human Population Growth
1. The MDCs - more developed countries
a. growth rate as a whole .1%, down from 1850-1950 when the population doubled
b. US growth rate .6%, immigrants, baby boom
c. total population expected to be at 1.2 billion by 2050
2. The LDCs - less-developed countries
a. growth rate at 1.6%
b. by 2050, population expected to jump from 5 to 8 billion
2. Comparing age structure
a. 3 age groups: prereproductive, reproductive, postreproductive
b. LDCs growth will continue, more young women in reproductive years
c. other than the US, MDCs have a stabilized age-structure diagram
Figure 24.1 from the text shows the human population growth.
Figure 24.2 shows the age-structure diagrams for MDCs and LDCs.
B. Human Use of Resources and Pollution
1. Land
a. beaches and human habitation - people like to live near the coastline - a place for fish spawning, habitats for terrestrial species, protection for coastal areas during storms
b. semiarid lakes and human habitation - humans allow animals to overgraze, they clear the land, use for fuel, fodder, water then runs off instead of being aborbed by remaining plants or replenishing wells, land becomes lifeless desert=desertification
c. tropical rain forest and human habitation - deforestation in tropical rain forests can cause desertification, loss of biodiversity
2. Water
a. increasing water supplies
i. dams - provide water, electricity. Rivers not making it to oceans, water loss to evaporation & seepage to rock beds, increase salinity, silt buildup
ii. aquifers - rain collected over hundreds of thousands of years ago, resource depletion - causes subsidence, sinkholes, saltwater intrusion
b. conservation of water - drought, salt-tolerant crops, drip irrigation, industries adopting conservation measures
3. Food food supply has increased since the 50s
a. modern/harmful farming methods - monoculture, fertilizers (production energy intensive, water pollution, kills good soil bacteria), irrigation, fuel consumption
b. positive practices - polyculture, contour farming, no-till
c. soil loss and degradation - erosion of topsoil (richest soil), sediment ends up in lakes and streams
d. green revolutions - varieties developed to yield more for in LDCs required same amount of fertizlier, water, pesticides, genetic engineering
e. domestic livestock - accounts for much pollution associated w/farming. 2/3 of cropland in US devoted to grow feed livestock. Much energy required to make food to feed livestock
Figure 24.10 from the text shows several methods of conservation.
4. Energy
a. nonrenewable sources - nuclear power, fossil fuels
b. burning of fossil fuels emites gases - rising temps threaten melting of glaciers, habitats threatened
c. renewable sources - hydropower, geothermal energy, wind power, solar
d. solar-hydrogen - using solar power to extract hyrdogen from water via electrolysis. Hydrogen can then be used as a clean-burning fuel
Figure 24.12 from the text shows 4 types of renewable energy sources.
5. Minerals
a. eg. fossil fuels, nonmetallic raw materials (sand, gravel, phosphate), metals (aluminum, copper, iron, lead, gold)
b. harmful to humans - heavy metals: lead, mercury, arsenic, cadmium, tin, chromium, zinc, and copper. Used to make batteries, electronics, pesticides, medicines, paints, inks, dyes
c. hazardous wastes - contributed by the consumption of minerals
d. 4 most common heavy metal contaminants - lead, arsenic, cadmium, chromium
e. 5 most common synthetic organic cmpds - trichloroethylene, toluene, benzene, polychlorinated biphenyls (PCBs), and cloroform.
f. synthetic organic chemicals - halogentaed hydrocarbons, used in production of plastics, pesticides, cosmetics, coatings, solvents...Chlorofluorocarbons (CFCs) - thinning of Earth's ozone. MDCs no longer use.
C. Biodiversity
1. Loss of biodiversity
a. habitat loss due to human interference
b. alien species
c. pollution - acid deposition, global warming, ozone depletion, synthetic organic chemicals
d. overexploitation
e. disease
2. Direct value of biodiversity
a. medicinal value - rosy periwinkle, penicillin, limulus in blood of horseshoe crab
b. agricultural value - natural predators, pollinators
c. consumptive use value - aquatic organisms, wild fruits, vegetables, trees
3. Indirect value of biodiversity
a. waste disposal - decomposers extremely useful to humans
b. provision of freshwater - after a storm forests soak up water and then release over a long period of time, preventing flooding
c. prevention of soil erosion - deforestation causes erosion, erosion causes silt buildup in dams and ecosystems
d. biogeochmeical cycles - keeps excess pollutants in environment under control
e. regulation of climate - trees provide shade, take up CO2, when cut, they release CO2, contributing to global warming
f. ecotourism
Figure 24.17 from the text provide examples of the direct benefits of wildlife.
D. Working Toward a Sustainable Society
1. Today's sustainable society
a. overpopulation of LDCs and overconsumption by MDCs both account for increasing poullution and extinction of wildlife
b. land used for human purposes
c. agriculture - big use of fossil fuels, use of pesticides, create pollution, use of freshwater
d. demand on freshwater
e. growing demand on energy sources
2. Characteristics of a sustainable society
a. use renewable energy
b. recycle materials
c. protect natural ecosystems
d. efficiency
e. rural sustainability - preserve ecosystems, cover crops, multiuse farming, composting, low flow or trickle irrigation, cultivars, precision farming, integrated pest management, plant variety of species, multipurpose trees, protect wetlands, buy local
f. urban sustainability - energy efficient transportation sys, solar/geothermal energy, green roofs, improve storm water mgmt, plant native grasses, greenbelts, revitalize old sections before developing new, control light and noise pollution, encourage recycling
3. Assessing economic well-being and quality of life
a. GNP - strictly economic
b. ISEW (index of sustainable economic welfare) - takes into account forms of value in addition to monetary value (environmental damage, natural resource depletion, distributional equite etc)
c. GPI (genuine progress indicator) - considers quality of life
d. use value, option value, existence value, aesthetic value, cultural value, scientific & educational value
Figure 24.18 from the text shows several unsustainable activities.
Definitions from Chapter 24 can be found here.
REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).
Links provided throughout the summary take you to online sources.
IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).
Friday, July 11, 2008
Unit 4, Online Lab #1: Embryonic & Fetal Development
LIST OF TEN SIGNIFICANT EVENTS DURING EMBRYONIC AND FETAL DEVELOPMENT
--quick description of what the event is
--when (hour, week, day or month) during development when it occurs
--why you think it is significant
--image or photo of that event or stage for five of the events
Fertilization
description: Union of egg and sperm in the oviduct
timing: 0 to 24 hours post-ovulation
significance: A required step. Many steps leading up to fertilization must occur for it to be successful. Many things can go wrong preventing its occurrence.
Cleavage
description: Duplication division.
timing: 1.5 to 3 days post-ovulation
significance: It is the first instance of mitotic cell division. All daughter cells receive the full 46 chromosomes.
Blastocyst
description: The morula moves down from the oviduct into the uterus. Cells flatten and form a hallow cavity. The flattened cells form an inner cell mass. The structure is now called a blastocyst.
timing: 4 days post-ovulation
significance: The cells that make up the inner cell mass will later become the embryonic disk. The outer cells walls will become the chorion. The chorion will contribute to the formation of the placenta.
Implantation
description: The blastocyst continues down into the uterus and secretes enzymes that allow it to implant in the uterine wall.
timing: 5 to 8 days post-ovulation
significance: A required step. Without implantation, the pregnancy will not continue.
Embryonic disk
description: Formation of embryonic disk
timing: 8 to 12 days post-ovulation
significance: Marks the start of gastrulation. The embryonic disk will later form the primary germ layers.
Primary germ layers
description: The embryonic disk forms tissue layers called the primary germ layers.
timing: 13 days post-ovulation
significance: All of the organs and tissues in an adult human can be traced back to the 3 primary germ layers, ectoderm, mesoderm, and endoderm.
Nervous system / heart
description: The nervous system becomes visually evident. Development of the heart begins.
timing: 21 to 23 days post-ovulation
significance: The nervous system will continue to develop leading to reflexes that are required for survival later in life. The heart will continue to develop allowing oxygen rich blood to reach tissues and organs
Bones
description: Cartilage starts to be replaced by bones.
timing: 3rd month
significance: The skeleton contributes to so many important functions: movement, support, protection, production of red blood cells, storage of minerals and fat.
Movement
description: The mother begins to feel movement.
timing: 5th to 7th month
significance: Although the fetus will begin moving sooner (which is equally important), this is an important moment for the mother. A potentially life changing experience.
Lungs
description: The lungs are capable of breathing air.
timing: 23 to 26 weeks post-ovulation
significance: The surfactant secreted by the lungs prevents them from sticking together. If born premature, the lungs of a child born at this stage can perform gas exchange.
--quick description of what the event is
--when (hour, week, day or month) during development when it occurs
--why you think it is significant
--image or photo of that event or stage for five of the events
Fertilization
description: Union of egg and sperm in the oviduct
timing: 0 to 24 hours post-ovulation
significance: A required step. Many steps leading up to fertilization must occur for it to be successful. Many things can go wrong preventing its occurrence.
Cleavage
description: Duplication division.
timing: 1.5 to 3 days post-ovulation
significance: It is the first instance of mitotic cell division. All daughter cells receive the full 46 chromosomes.
Blastocyst
description: The morula moves down from the oviduct into the uterus. Cells flatten and form a hallow cavity. The flattened cells form an inner cell mass. The structure is now called a blastocyst.
timing: 4 days post-ovulation
significance: The cells that make up the inner cell mass will later become the embryonic disk. The outer cells walls will become the chorion. The chorion will contribute to the formation of the placenta.
Implantation
description: The blastocyst continues down into the uterus and secretes enzymes that allow it to implant in the uterine wall.
timing: 5 to 8 days post-ovulation
significance: A required step. Without implantation, the pregnancy will not continue.
Embryonic disk
description: Formation of embryonic disk
timing: 8 to 12 days post-ovulation
significance: Marks the start of gastrulation. The embryonic disk will later form the primary germ layers.
Primary germ layers
description: The embryonic disk forms tissue layers called the primary germ layers.
timing: 13 days post-ovulation
significance: All of the organs and tissues in an adult human can be traced back to the 3 primary germ layers, ectoderm, mesoderm, and endoderm.
Nervous system / heart
description: The nervous system becomes visually evident. Development of the heart begins.
timing: 21 to 23 days post-ovulation
significance: The nervous system will continue to develop leading to reflexes that are required for survival later in life. The heart will continue to develop allowing oxygen rich blood to reach tissues and organs
Bones
description: Cartilage starts to be replaced by bones.
timing: 3rd month
significance: The skeleton contributes to so many important functions: movement, support, protection, production of red blood cells, storage of minerals and fat.
Movement
description: The mother begins to feel movement.
timing: 5th to 7th month
significance: Although the fetus will begin moving sooner (which is equally important), this is an important moment for the mother. A potentially life changing experience.
Lungs
description: The lungs are capable of breathing air.
timing: 23 to 26 weeks post-ovulation
significance: The surfactant secreted by the lungs prevents them from sticking together. If born premature, the lungs of a child born at this stage can perform gas exchange.
Thursday, July 10, 2008
Compendium Review Unit 4 Major Topic: Reproduction
I. Reproductive System
A. Human Life Cycle
B. Male Reproductive System
C. Female Reproductive System
E. Female Hormone Levels
F. Control of Reproduction
G. Sexually Transmitted Diseases
II. Development and Aging
A. Fertilization
B. Pre-Embryonic and Embryonic Development
C. Fetal Development
D. Pregnancy and Birth
E. Development after Birth
I. Reproductive System
A. Human Life Cycle
1. Functions of reproductive organs
a. production
b. transport
c. delivery
d. fertilization, nourishment
e. hormones
2. Mitosis and meiosis
a. mitosis - duplication division for growth and repair, diploid # 46 chromosomes
b. meiosis - reduction division, to produce sex cells, haploid # 23 chromosomes
B. Male Reproductive System
1. Organs - testes, epididymides, vasa deferentia, seminal vesicles, prostate
gland, urethra, bulbourethral glands, penis - see definitions for functions
Figure 16.2 from the text illustrates the male reproductive system
2. Orgasm in males
a. nitric oxide release leads to production of cGMP (cyclic guanosine monophosphate)
b. cGMP cuases smooth muscle of incoming arterial walls to relax
c. erectile tissue fills with blood
d. outgoing venous walls compress, erection
e. sperm enter urethra from each vas deferens, glands contribute secretions
3. Male gonads, the testes
a. seminiferous tubules - location of spermatogenesis, Sertoli cells
b. interstitial cells - lie between seminiferous tubules, secrete androgens
Figure 16.4 from the text depicts the testis and sperm and spermatogenesis.
4. Hormonal regulation in males
a. hypothalamus secretes GnRH
b. GnRH stimulates anterior pituitary to secrete gonadotropic hormones (FSH, LH)
c. GnRH, FSH, LH involved in neg feedback relationship - maintains constant production of sperm and testosterone
C. Female Reproductive System
1. The genital tract
a. egg - ovary->fimbriae->cilia/oviduct->uterus, lives 6-24 hrs unless fertiized
b. fertilization (zygote formation) usually takes place in oviduct
c. implantation after several days
d. uterus, endometrium, cervix, vagina
Figure 16.6 from the text illustrates the female reproductive system.
2. External genitals vulva: labia majora, mons pubis, labia minora, glans clitoris, urethra, vagina
3. Orgasm in females
a. labia minora, vaginal wall, clitoris engorge with blood
b. blood vessels in vaginal wall & mucus-secreting glands beneath labia minor secrete lubricating fluid
D. Female Hormone Levels
1. Ovarian cycle (phases): nonpregnant
a. hypothalamus secretes GnRH
b. GnRH stimulates anterior pituitary to secrete gonadotropic hormones (FSH, LH)
c. FSH & LH not present in constant amounts, secreted at different rates during cycle
d. follicular phase - FSH promotes development of follicles that secrete estrogen
e. estrogen level in blood provides neg feedback to ant pituitary secretion of FSH - ends follicular phase
f. spike in estrogen - large amt of GnRH secreted - surge of LH - ovulation day 14
g. luteal phase - LH promotes development of corpus luteum - secretes progesterone
Figure 16.8 from the text illustrates the ovarian cycle and shows oogenesis.
2. Estrogen and progesterone
Figure 16.10 from the text shows the female hormone levels during a complete menstrual cycle (no pregnancy).
3. Uterine cycle: nonpregnant
4. Fertilization and pregnancy
a. fertilization occurs in oviduct
b. pregnancy begins when developing embryo implants in endometrium
c. placenta produces HCG which stimulates corpus luteum to produce more progesterone
d. progesterone shuts down hypothalamus & anterior pituitary - prevent new
follicles from beginning
Figure 16.11 shows the effect of pregnancy on female hormone levels.
E. Control of Reproduction
1. Birth control methods
a. abstinence
b. contraceptives - birth control pill, IUD, diaphragm, female & male condums, implants, injections, vaccines
c. vasectomy and tubal ligation
d. morning after pills
2. Infertility
a. causes
i. male - low sperm, abnormal sperm=temperature, sedentary, smoking, alcohol
ii. female - body weight=small follicles; blocked oviducts=pelvic inflammatory disease, endometriosis
b. assisted reproductive technologies
i. artificial insemination by donor (AID), intrauterine insemination (IUI)
ii. in vitro fertilization (IVF)
iii. gamete intrafallopian transfer (GIFT)
iv. surrogate mothers
v. intracytoplasmic sper injection (ICSI)
F. Sexually Transmitted Diseases
1. STDs caused by viruses
a. HIV infections - primary host is helper T lymphocyte, immune system becomes severly impaired, treatment=HART
b. genital warts caused by human papillomaviruses
c. genital herpes caused by herpes simplex virus
d. hepatitis infects the liver
2. STDs caused by bacteria
a. chlamydia (chlamydia trachomatis) - burning during urination, mucoid discharge
b. gonorrhea (neisseria gonorrhoeae) - pain upon urination, greenish yellow urethral discharge, can spread to eyes, mouth throat
c. syphilis (treponema pallidum) - chancre, rash, affects cardiovascular sys
3. Two other infections
a. bacterial vaginosis (gardnerella vainalis)
b. trichomonas vainalis, candida albicans
Definitions for Chapter 16 can be found here.
II. Development and Aging
A. Fertilization
1. Steps of fertilization
a. egg plasma membrane - zona pellucida (extracellular matrix), corona radiata (follicular cells)
b. sperm penetrate zona pellucida, 1 enters cell after acrosome forges pathway through zp, sperm and egg membranes fuse
c. upon sperm touching egg, egg's plasma membrane depolarizes
d. only sperm nucleus fuses to egg
Figure 17.1 from the text illustrates the steps of fertilization.
B. Pre-Embryonic and Embryonic Development
1. Processes of development
a. cleavage - mitotic cell division, no increase in size, each cell rcvs full complement of chromosomes and genes
b. growth - cell division accompanied by increase in size of daughter cells
c. morphogenesis - shaping of embryo, certain cells migrate in relation to other cells
d. differentiation - cells take on specific structure and function, 1st sys to become visibly differentiated is nervous sys
2. Extraembryonic membranes named for function in shelled animals
a. chorion - develops into fetal half of placenta - provides nourishment, oxygen, removes waste, blood vessels w/in chorionic villi - continuous w/umbilical blood vessels
b. allantois - collects urine, later becomes bladder, its blood vessels become umbilical blood vessels (umbilical arteries - O2 poor, umbilical veins - O2 rich)
c. yolk sac - first embryonic membrane to appear, contains many blood vessels, first site of blood cell formation
d. amnion - enlarges w/embryo/fetus, fluid cushion
Figure 17.2 from the text illustrates the extraembryonic membranes.
3. Stages of development
a. pre-embryonic development - first week, zygote->morula->blastocyst
Figure 17.3 from the text illustrates pre-embryonic development.
b. embryonic development - 2nd wk
i. implantation chorion secretes enzymes and HCG
ii. HCG serves to maintain corpus luteum-> secretes progesterone so endometrium maintained (no menstruation)
iii. inner cell mass via gastrulation-> embryonic disk, yolk sac, & amniotic cavity
iv. primary germ layers formed from embryonic disk
c. embryonic development - 3rd wk
i. nervous sys - first to be visible
ii. heart development begins
d. embryonic development - 4th & 5th wk
i. body stalk connects embryo to chorion
ii. allantois in body stalk
iii. head and tail lift, body stalk moves anteriorly => umbilical cord
iv. limb buds appea
v. head enlarges, sense organs become more prominent, eyes, ears, nose apparent
Figure 17.6 from the text shows and illustrates a human embryo at the beginning of the fifth week.
e. embryonic development - 6th thru 8th weeks
i. embryo changes to form that resembles human being
ii. neck region develops, head in normal relationship with body
iii. nervous sys development allow reflex actions
Figure 17.4 from the text illustrates the stages of embryonic development.
Figure 17.5 from the text illustrates the course of development for the 3 primary germ layers.
C. Fetal Development
1. functions of progesterone & estrogen during pregnancy (source is placenta)
a. neg feedback on hypothalamus & anterior pituitary - prevent new follicles from maturing
b. maintain endometrium - no menstruation
2. Path of fetal bloodexchange of nutrients, oxygen, wastes is across chorionic villi
Figure 17.7 from the text shows the path of fetal cirulation.
3. Events of fetal development
a. 3rd and 4th months
i. head growth slows
ii. hair develops
iii. cartilage gets replaced by bone
iv. distinguish male from female
v. heartbeat heard with stethoscope
b. 5th through 7th months
i. movement felt by mom
ii. fetal position
iii. eyelids open
iv. lanugo & vernix caseosa
c. 8th through 9th months
i. weight gain 1 lb per week
ii. fetus rotates, head pointed down
4. Development of male and femal genitals differentiation depends on hormones present
a. normal development of the genitals
i. internal genitals - gonads develop during 7th wk
ii. prior to 7th wk, males & females both have Mullerian & Wolffian ducts
iii. external genitals
iv. small bud, urogenital groove
b. abnormal development of the genitals
i. presence or absence of SRY gene can cause XY female or XX male syndrome
ii. SRY gene causes testes to form, testes secrete: testosterone, anti-Mullerian hormone, dihydrotestosterone
iii. ambiguous sex determination - androgen insensitivity syndrome (plasma membrane receptors for testosterone ineffective), male pseudohermaphroditism
Figure 17.9 from the text illustrates the development of the internal and external genitals in males and females.
D. Pregnancy and Birth
1. energy level fluctuates, increase in weight
2. progesterone - relaxes smooth muscle-uterus & arterial walls, low blood pressure: renin-angiotensin-aldosterone mechanism by estrogen
a. aldosterone - sodium, water intake, blood volume increases 40%
b. increase in red blood cells, cardiac output increases 20-30%
3. Pulmonary values increase
a. increase in uterus size pushes internal organs superiorly, widens thoracic cavity
b. carbon dioxide levels fall - concentration gradient favorable to flow of CO2 from fetal blood
4. Other effects
a. enlargement of uterus compresses bladder and ureters
b. compression of inferior vena cava - decreases venous return=> edema varicose veins
c. placent produces peptide hormones - one makes cells resistant to insulin
d. striae gravidarum, darkening of skin
5. Birth
a. positive feedback - cervix stretches - causes uterine contractions & release of oxytocin from posterior pituitary gland
b. oxytocin stimulates uterine muscles
c. uterine contractions push fetus down, cervix stretches more cycle continues
6. Stage 1
a. effacement - cervical canal slowly disappears, babies head acts as wedge to assist cervical dilation
7. Stage 2
a. contractions - 1 minute each, 1-2 minutes apart
b. back of head faces up
c. episiotomy
d. umbilical cord cut & tied
8. Stage 3
a. afterbirth expelled
Figure 17.11 from the text shows the birthing process.
E. Development after Birth
1. Hypotheses of aging
a. genetic in origin - mitochondrial hypothesis of aging
b. whole-body process - changes to hormonal system, immune system, changes to tissue
c. extrinsic factors - diet, exercise, habits
2. Effect of age on body systems
a. skin - becomes thinner & less elastic; less adipose tissue in subcutaneous layer; sagging, wrinkling caused by loss of thickness. fewer sweat glands - skin cracks, fewer hair follicles
b. processing and transporting
i. heart shrinks, reduced cardiac output
ii. arteries harden, blood pressure rises over time
iii. blood flow to liver reduced, drugs not metabolized as efficeiently - lower doses required
iv. blood supply to kidneys reduced
v. loss of teeth
c. integration and coordination
i. loss in short-term memory, but can learn and remember new material
ii. neuron death may be due to reduced blood flow
iii. reaction time slows, more stimulation needed for senses
iv. hearing impacted
v. loss of skeletal muscle, reduction of bone density
d. the reproductive system
i. menopause, andropause
Definitions for Chapter 17 can be found here.
REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).
Links provided throughout the summary take you to online sources.
IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).
A. Human Life Cycle
B. Male Reproductive System
C. Female Reproductive System
E. Female Hormone Levels
F. Control of Reproduction
G. Sexually Transmitted Diseases
II. Development and Aging
A. Fertilization
B. Pre-Embryonic and Embryonic Development
C. Fetal Development
D. Pregnancy and Birth
E. Development after Birth
I. Reproductive System
A. Human Life Cycle
1. Functions of reproductive organs
a. production
b. transport
c. delivery
d. fertilization, nourishment
e. hormones
2. Mitosis and meiosis
a. mitosis - duplication division for growth and repair, diploid # 46 chromosomes
b. meiosis - reduction division, to produce sex cells, haploid # 23 chromosomes
B. Male Reproductive System
1. Organs - testes, epididymides, vasa deferentia, seminal vesicles, prostate
gland, urethra, bulbourethral glands, penis - see definitions for functionsFigure 16.2 from the text illustrates the male reproductive system
2. Orgasm in males
a. nitric oxide release leads to production of cGMP (cyclic guanosine monophosphate)
b. cGMP cuases smooth muscle of incoming arterial walls to relax
c. erectile tissue fills with blood
d. outgoing venous walls compress, erection
e. sperm enter urethra from each vas deferens, glands contribute secretions
3. Male gonads, the testes
a. seminiferous tubules - location of spermatogenesis, Sertoli cells
b. interstitial cells - lie between seminiferous tubules, secrete androgens
Figure 16.4 from the text depicts the testis and sperm and spermatogenesis.
4. Hormonal regulation in males
a. hypothalamus secretes GnRH
b. GnRH stimulates anterior pituitary to secrete gonadotropic hormones (FSH, LH)
c. GnRH, FSH, LH involved in neg feedback relationship - maintains constant production of sperm and testosterone
C. Female Reproductive System
1. The genital tract
a. egg - ovary->fimbriae->cilia/oviduct->uterus, lives 6-24 hrs unless fertiized
b. fertilization (zygote formation) usually takes place in oviduct
c. implantation after several days
d. uterus, endometrium, cervix, vagina
Figure 16.6 from the text illustrates the female reproductive system.
2. External genitals vulva: labia majora, mons pubis, labia minora, glans clitoris, urethra, vagina
3. Orgasm in females
a. labia minora, vaginal wall, clitoris engorge with blood
b. blood vessels in vaginal wall & mucus-secreting glands beneath labia minor secrete lubricating fluid
D. Female Hormone Levels
1. Ovarian cycle (phases): nonpregnant
a. hypothalamus secretes GnRH
b. GnRH stimulates anterior pituitary to secrete gonadotropic hormones (FSH, LH)
c. FSH & LH not present in constant amounts, secreted at different rates during cycle
d. follicular phase - FSH promotes development of follicles that secrete estrogen
e. estrogen level in blood provides neg feedback to ant pituitary secretion of FSH - ends follicular phase
f. spike in estrogen - large amt of GnRH secreted - surge of LH - ovulation day 14
g. luteal phase - LH promotes development of corpus luteum - secretes progesterone
Figure 16.8 from the text illustrates the ovarian cycle and shows oogenesis.
2. Estrogen and progesterone
Figure 16.10 from the text shows the female hormone levels during a complete menstrual cycle (no pregnancy).
3. Uterine cycle: nonpregnant
4. Fertilization and pregnancy
a. fertilization occurs in oviduct
b. pregnancy begins when developing embryo implants in endometrium
c. placenta produces HCG which stimulates corpus luteum to produce more progesterone
d. progesterone shuts down hypothalamus & anterior pituitary - prevent new
follicles from beginningFigure 16.11 shows the effect of pregnancy on female hormone levels.
E. Control of Reproduction
1. Birth control methods
a. abstinence
b. contraceptives - birth control pill, IUD, diaphragm, female & male condums, implants, injections, vaccines
c. vasectomy and tubal ligation
d. morning after pills
2. Infertility
a. causes
i. male - low sperm, abnormal sperm=temperature, sedentary, smoking, alcohol
ii. female - body weight=small follicles; blocked oviducts=pelvic inflammatory disease, endometriosis
b. assisted reproductive technologies
i. artificial insemination by donor (AID), intrauterine insemination (IUI)
ii. in vitro fertilization (IVF)
iii. gamete intrafallopian transfer (GIFT)
iv. surrogate mothers
v. intracytoplasmic sper injection (ICSI)
F. Sexually Transmitted Diseases
1. STDs caused by viruses
a. HIV infections - primary host is helper T lymphocyte, immune system becomes severly impaired, treatment=HART
b. genital warts caused by human papillomaviruses
c. genital herpes caused by herpes simplex virus
d. hepatitis infects the liver
2. STDs caused by bacteria
a. chlamydia (chlamydia trachomatis) - burning during urination, mucoid discharge
b. gonorrhea (neisseria gonorrhoeae) - pain upon urination, greenish yellow urethral discharge, can spread to eyes, mouth throat
c. syphilis (treponema pallidum) - chancre, rash, affects cardiovascular sys
3. Two other infections
a. bacterial vaginosis (gardnerella vainalis)
b. trichomonas vainalis, candida albicans
Definitions for Chapter 16 can be found here.
II. Development and Aging
A. Fertilization
1. Steps of fertilization
a. egg plasma membrane - zona pellucida (extracellular matrix), corona radiata (follicular cells)
b. sperm penetrate zona pellucida, 1 enters cell after acrosome forges pathway through zp, sperm and egg membranes fuse
c. upon sperm touching egg, egg's plasma membrane depolarizes
d. only sperm nucleus fuses to egg
Figure 17.1 from the text illustrates the steps of fertilization.
B. Pre-Embryonic and Embryonic Development
1. Processes of development
a. cleavage - mitotic cell division, no increase in size, each cell rcvs full complement of chromosomes and genes
b. growth - cell division accompanied by increase in size of daughter cells
c. morphogenesis - shaping of embryo, certain cells migrate in relation to other cells
d. differentiation - cells take on specific structure and function, 1st sys to become visibly differentiated is nervous sys
2. Extraembryonic membranes named for function in shelled animals
a. chorion - develops into fetal half of placenta - provides nourishment, oxygen, removes waste, blood vessels w/in chorionic villi - continuous w/umbilical blood vessels
b. allantois - collects urine, later becomes bladder, its blood vessels become umbilical blood vessels (umbilical arteries - O2 poor, umbilical veins - O2 rich)
c. yolk sac - first embryonic membrane to appear, contains many blood vessels, first site of blood cell formation
d. amnion - enlarges w/embryo/fetus, fluid cushion
Figure 17.2 from the text illustrates the extraembryonic membranes.
3. Stages of development
a. pre-embryonic development - first week, zygote->morula->blastocyst
Figure 17.3 from the text illustrates pre-embryonic development.
b. embryonic development - 2nd wki. implantation chorion secretes enzymes and HCG
ii. HCG serves to maintain corpus luteum-> secretes progesterone so endometrium maintained (no menstruation)
iii. inner cell mass via gastrulation-> embryonic disk, yolk sac, & amniotic cavity
iv. primary germ layers formed from embryonic disk
c. embryonic development - 3rd wk
i. nervous sys - first to be visible
ii. heart development begins
d. embryonic development - 4th & 5th wk
i. body stalk connects embryo to chorion
ii. allantois in body stalk
iii. head and tail lift, body stalk moves anteriorly => umbilical cord
iv. limb buds appea
v. head enlarges, sense organs become more prominent, eyes, ears, nose apparent
Figure 17.6 from the text shows and illustrates a human embryo at the beginning of the fifth week.
e. embryonic development - 6th thru 8th weeks
i. embryo changes to form that resembles human being
ii. neck region develops, head in normal relationship with body
iii. nervous sys development allow reflex actions
Figure 17.4 from the text illustrates the stages of embryonic development.
Figure 17.5 from the text illustrates the course of development for the 3 primary germ layers.
C. Fetal Development
1. functions of progesterone & estrogen during pregnancy (source is placenta)a. neg feedback on hypothalamus & anterior pituitary - prevent new follicles from maturing
b. maintain endometrium - no menstruation
2. Path of fetal bloodexchange of nutrients, oxygen, wastes is across chorionic villi
Figure 17.7 from the text shows the path of fetal cirulation.
3. Events of fetal development
a. 3rd and 4th months
i. head growth slows
ii. hair develops
iii. cartilage gets replaced by bone
iv. distinguish male from female
v. heartbeat heard with stethoscope
b. 5th through 7th months
i. movement felt by mom
ii. fetal position
iii. eyelids open
iv. lanugo & vernix caseosa
c. 8th through 9th months
i. weight gain 1 lb per week
ii. fetus rotates, head pointed down
4. Development of male and femal genitals differentiation depends on hormones present
a. normal development of the genitals
i. internal genitals - gonads develop during 7th wk
ii. prior to 7th wk, males & females both have Mullerian & Wolffian ducts
iii. external genitals
iv. small bud, urogenital groove
b. abnormal development of the genitals
i. presence or absence of SRY gene can cause XY female or XX male syndrome
ii. SRY gene causes testes to form, testes secrete: testosterone, anti-Mullerian hormone, dihydrotestosterone
iii. ambiguous sex determination - androgen insensitivity syndrome (plasma membrane receptors for testosterone ineffective), male pseudohermaphroditism
Figure 17.9 from the text illustrates the development of the internal and external genitals in males and females.
D. Pregnancy and Birth
1. energy level fluctuates, increase in weight
2. progesterone - relaxes smooth muscle-uterus & arterial walls, low blood pressure: renin-angiotensin-aldosterone mechanism by estrogen
a. aldosterone - sodium, water intake, blood volume increases 40%
b. increase in red blood cells, cardiac output increases 20-30%
3. Pulmonary values increase
a. increase in uterus size pushes internal organs superiorly, widens thoracic cavity
b. carbon dioxide levels fall - concentration gradient favorable to flow of CO2 from fetal blood
4. Other effects
a. enlargement of uterus compresses bladder and ureters
b. compression of inferior vena cava - decreases venous return=> edema varicose veins
c. placent produces peptide hormones - one makes cells resistant to insulin
d. striae gravidarum, darkening of skin
5. Birth
a. positive feedback - cervix stretches - causes uterine contractions & release of oxytocin from posterior pituitary gland
b. oxytocin stimulates uterine muscles
c. uterine contractions push fetus down, cervix stretches more cycle continues
6. Stage 1
a. effacement - cervical canal slowly disappears, babies head acts as wedge to assist cervical dilation
7. Stage 2
a. contractions - 1 minute each, 1-2 minutes apart
b. back of head faces up
c. episiotomy
d. umbilical cord cut & tied
8. Stage 3
a. afterbirth expelled
Figure 17.11 from the text shows the birthing process.
E. Development after Birth
1. Hypotheses of aging
a. genetic in origin - mitochondrial hypothesis of aging
b. whole-body process - changes to hormonal system, immune system, changes to tissue
c. extrinsic factors - diet, exercise, habits
2. Effect of age on body systems
a. skin - becomes thinner & less elastic; less adipose tissue in subcutaneous layer; sagging, wrinkling caused by loss of thickness. fewer sweat glands - skin cracks, fewer hair follicles
b. processing and transporting
i. heart shrinks, reduced cardiac output
ii. arteries harden, blood pressure rises over time
iii. blood flow to liver reduced, drugs not metabolized as efficeiently - lower doses required
iv. blood supply to kidneys reduced
v. loss of teeth
c. integration and coordination
i. loss in short-term memory, but can learn and remember new material
ii. neuron death may be due to reduced blood flow
iii. reaction time slows, more stimulation needed for senses
iv. hearing impacted
v. loss of skeletal muscle, reduction of bone density
d. the reproductive system
i. menopause, andropause
Definitions for Chapter 17 can be found here.
REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).
Links provided throughout the summary take you to online sources.
IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).
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