Unit 4 - Human Populations: Reproduction and Ecology
Major Topic I: Reproduction
Chapter 16 – Reproductive System
16.1 Human Life Cycle
16.2 Male Reproductive System
16.3 Female Reproductive System
16.4 Female Hormone Levels
16.5 Control of Reproduction
16.6 Sexually Transmitted Diseases
Chapter 17 – Development and Aging
17.1 Fertilization
17.2 Pre-Embryonic and Embryonic Development
17.3 Fetal Development
17.4 Pregnancy and Birth
17.5 Development After Birth
Major Topic II: Human Landscapes
Chapter 22 – Human Evolution
22.1 Origin of Life
22.2 Biological Evolution
22.3 Classification of Humans
22.4 Evolution of Hominids
22.5 Evolution of Humans
Chapter 23 – Global Ecology and Human Interferences
23.1 The Nature of Ecosystems
23.2 Energy Flow
23.3 Global Biogeochemical Cycles
Chapter 24 – Human Population, Planetary Resources, and Conservation
24.1 Human Population Growth
24.2 Human Use of Resources and Pollution
24.3 Biodiversity
24.4 Working Toward a Sustainable Society
Embryonic and Fetal Development Online Lab Write-Up
Human Demographics Online Lab Write-Up
Lab Project Write-Up – Interaction with other species
Ethical Issue Essay
Reflection on course work – self evaluation
Major Topic I: Reproduction
Chapter 16 – Reproductive System
16.1 Human Life Cycle
The life cycle of higher organisms requires two types of cell division: mitosis and meiosis.
• Mitosis: growth and repair of tissues.
• Meiosis: gamete production.
16.2 Male Reproductive System
The external genital of males are:
• The penis which is used for sexual intercourse
• The scrotum which contains the testes – Spermatogenesis, occurring in seminiferous tubules of the testes, produces sperm.
• Mature sperm are stored in the epididymides
• Sperm pass from the vasa deferentia to the urethra
• The seminal vesicles, prostate gland, and bulbourethral glands add gluids by secretion to sperm
• Sperm and secretions are called semen or seminal fluid.
Orgasm in males results in ejaculation of semen from the penis.
Hormonal Regulation in Males:
• Hormonal regulation, involving secretions from the hypothalamus, the anterior pituitary, and the testes, maintains a fairly constant level of testosterone.
• FSH from the anterior pituitary promotes spermatogenesis.
• LH from the anterior pituitary promotes testosterone production by interstitial cells.
16.3 Female Reproductive System
Oogenesis occurring within the ovaries typically produces one mature follicle each month.
• This follicle balloons out of the ovary and bursts, releasing an egg that enters an oviduct.
• The oviducts lead to the uterus, where implantation and development occur.
• The female external genital area includes the vaginal opening, the clitoris, the labia minora, and the labia majora.
• The vagina is the organ of sexual intercourse and the birth canal.
• Orgasm in females culminates in uterine and oviduct contractions.
16.4 Female Hormone Levels
Ovarian Cycle: Nonpregnant
• The ovarian cycle is under the hormonal control of the hypothalamus and the anterior pituitary.
• During the cycle’s first half, FSH from the anterior pituitary causes maturation of a follicle that secretes estrogen and some progesterone.
• After ovulation and during the cycle’s second half, LH from the anterior pituitary converts the follicle into the corpus luteum.
• The corpus luteum secretes progesterone and some estrogen.
Uterine Cycle: Nonpregnant
• Estrogen and progesterone regulate the unterine cycle.
• Estrogen causes the endometrium to rebuild.
• Ovulation usually occurs on day 14 of a 28 day cycle.
• Progesterone produced by the corpus luteum causes the endometrium to thicken and become secretory.
• A low level of hormones causes the endometrium to break down as menstruation occurs.
Fertilization and Pregnancy
• If fertilization takes place, the embryo implants itself in the thickened endometrium.
• The corpus luteum is maintained because of HCG production by the placenta, and therefore, progesterone production does not cease.
• Menstruation usually does not occur during pregnancy.
16.5 Control of Reproduction
Numerous birth control methods and devices are available.
• A few of these are the birth control pill, diaphragm, and condom.
• Effectiveness varies.
• Assisted reproductive technologies may help infertile couples to have children. Some of these technologies are:
o Artificial insemination by donor (AID)
o In vitro fertilization (IVF)
o Gamete intrafallopian transfer (GIFT)
o Intracytoplasmic sperm injection (ICSI)
16.6 Sexually Transmitted Diseases
STDs are caused by viruses, bacteria, protists, fungi, and animals.
STDs Caused by Viruses:
• AIDS is caused by HIV (human immunodeficiency virus).
• Genital warts are caused by human papillomaviruses; these viruses cause warts or lesions on genitals and are associated with certain cancers.
• Genital herpes is caused by herpes simplex virus type 2: causes blisters on genitals.
• Hepatitis is cause by hepatitis viruses A, B, C, D, E, and G. A and E are usually acquired from contaminated water; hepatitis B and C from blood borne transmission; and B, D, and G are sexually transmitted.
STDs Caused by Bacteria
• Chlamydia is caused by Chlamydia trachomatis: PID can result.
• Gonorrhea is caused by Neisseria gonorrhoeae; PID can result.
• Syphilis is cause by Treponema pallidum. It has three stages, with the third stage resulting in death.
Two Other Infections
• Bacterial vaginosis is caused by Gardnerella vaginalis.
• Trichomoniasis is an overgrowth of Candida albicans.
Chapter 17 – Development and Aging
17.1 Fertilization
The acrosome of a sperm releases enzymes that digest a pathway for the sperm through the zona pellucida. The sperm nucleus enters the egg and fuses with the egg nucleus.
17.2 Pre-Embryonic and Embryonic Development
• Cleavage, growth, and morphogenesis, and differentiation are the processes of development.
• The extraembryonic membranes (chorion, allantois, yolk sac, and amnion) function in internal development.
17.3 Fetal Development
• At the end of the embryonic period, all organ systems are established, and there is a mature and functioning placenta. The umbilical arteries and umbilical vein take blood to and from the placenta, where exchanges take place.
• Exchanges supply the fetus with oxygen and nutrients and rid the fetus of carbon dioxide and wastes.
• The venous duct joins the umbilical vein to the inferior vena cava.
• The oval duct and arterial duct allow the blood to pass through the heart without going to the lungs. Fetal development extends from the third through the ninth months.
• During the third and fourth months, the skeleton is becoming ossified.
• The sex of the fetus becomes distinguishable. If an SRY gene is present, testes and male genitals develop. Otherwise, ovaries and female genitals develop.
• During the fifth months, the fetus continues to grow and to gain weight.
17.4 Pregnancy and Birth
Major changes take place in the mother’s body during pregnancy.
• Weight gain occurs as the uterus occupies most of the abdominal cavity.
• Many complaints, such as constipation, heartburn, darkening of certain skin areas, and pregnancy-induced diabetes, are due to the presence of placental hormones.
Birth
• A positive feedback mechanism that involves uterine contractions and oxytocin explain the onset and continuation of labor.
• During stage 1 of birth, the cervix dilates.
• During stage 2, the child is born.
• During stage 3, the afterbirth is expelled.
17.5 Development After Birth
Development after birth consists of infancy, childhood, adolescence, and adulthood.
• Aging encompasses progressive changes from about age 20 on that contribute to an increased risk of infirmity, disease, and death.
Hypothesis on Aging
• Aging by have a genetic basis.
• Aging may be due to changes that affect the whole body
• Aging may be due to extrinsic factors like diet and exercise.
Effect of Age on Body Systems
• Deterioration of organ systems can possibly be prevented or reduced in part by utilizing good health habits.
Major Topic II: Human Landscapes
Chapter 22 – Human Evolution
22.1 Origin of Life
A chemical evolution could have produced the protocell.
• Using an outside energy source, small organic molecules were produced by reactions between early Earth’s atmospheric gases.
• Macromolecules evolved and interacted.
• The RNA-first hypothesis – only macromolecule RNA was needed for the first cell(s).
• The protein-first hypothesis – amino acids join to form polypeptides when exposed to dry heat.
• The protocell, a heterotrophic fermenter, lived on preformed organic molecules in the ocean.
The protocell eventually became a true cell once it had genes composed of DNA and could reproduce.
22.2 Biological Evolution
Biological evolution explains both the unity and diversity of life.
• Descent from a common ancestor explains the unity of living things.
• Adaptation to different environments explains the great diversity of living things.
• Fossil evidence supports evolution. The fossil record gives us the history of life in general and allows us to trace the descent of a particular group.
Darwin discovered much evidence for common descent.
• Biological evidence – The distribution of organisms on Earth is explainable by assuming that organisms evolved in one locale.
• Anatomical evidence – The common anatomies and development of a group of organisms are explainable by descent from a common ancestor.
• Biochemical evidence – All organisms have similar biochemical molecules.
Darwin developed a mechanism for adaptation known as natural selection.
The result of natural selection is a population adapted to its local environment.
22.3 Classification of Humans
The classification of humans can be used to trace their ancestry.
• Humans are primates
• A primate evolutionary tree shows that humans share a common ancestor with African apes.
22.4 Evolution of Hominids
• The first hominid most likely lived about 6-7 MYA.
• Certain features identify fossil hominids.
• Ardipithecines were most likely hominids
Evolution of Australopithecines
The evolutionary tree of hominids resembles a bush (not a straight line of fossils leading to modern humans).
• Australopithecines lived about 3 MYA.
• They could walk erect, but they had a small brain.
• This testifies to a mosaic evolution for humans (not all advanced features evolved at the same time).
22.5 Evolution of Humans
Fossils are classified as Homo with regard to their brain size (over 600cm3), jaws and teeth, and evidence of tool use.
• H.habilis made and used tools.
• H.erectus was the first Homo to have a brain size of more than 1000 cm3.
• H.erectus migrated from Africa into Europe and Asia.
• H. erectus used fire and may have been big-game hunters.
Evolution of Modern Humans
Two hypotheses of modern human evolution are being tested.
• The multiregional continuity hypothesis suggests that modern humans evolved separately in Europe, Africa, and Asia.
• The out-of-Africa hypothesis says that H.sapiens evolved in Africa but then migrated to Asia and Europe.
Neanderthals and Cro-Magnons
• The Neanderthals were already living in Europe and Asia before modern humans arrived.
• They had a culture, but did not have the physical traits of modern humans.
• Cro-Magnons are the oldest fossil to be designated H.sapiens. Their tools were sophisticated, and they had a culture.
Chapter 23 – Global Ecology and Human Interferences.
23.1 The Nature of Ecosystems
Ecology is the study of the interactions of organisms with each other and with the physical environment.
• Organisms interact with the physical and chemical environment, and the result is an ecosystem.
• Terrestrial ecosystems are forests, grasslands, and deserts, which includes the tundra.
• Aquatic ecosystems are either salt water or freshwater.
Biotic Components of an Ecosystem
• In a community, each population has a habitat and a niche.
• Autotrophs produce organic nutrients for themselves and others from inorganic nutrients and an outside energy source.
• Heterotrophs consume organic nutrients.
• Consumers are herbivores, carnivores, and omnivores.
• Decomposers feed on detritus, releasing inorganic substances back into the ecosystem.
Energy Flow and Chemical Cycling
• Ecosystems are characterized by energy flow and chemical cycling.
• Energy flows through the populations of an ecosystem.
• Chemical cycle within and among ecosystems.
23.2 Energy Flow
Various interconnecting paths of energy flow are called food web.
• A food web is a diagram showing how carious organisms are connected by eating relationships.
• Grazing food webs begin with vegetation eaten by a herbivore that becomes food for a carnivore.
• Detrital food webs begin with detritus, food for decomposers and for detritivores.
• Members of detrital food webs can be eaten by above ground carnivores, joining the two food webs.
Trophic Levels
• A trophic level is all the organisms that feed at a particular link in a food chain.
• Ecological pyramids illustrate that biomass and energy content decrease from one trophic level to the next because of energy loss.
23.3 Global Biogeochemical Cycles
Chemicals circulate through ecosystems via biogeochemical cycles, pathways involving both biotic and geological components. Biogeochemical cycles:
• Can be gaseous or sedimentary.
• Have reservoirs that contain inorganic nutrients available to living things on a limited basis.
• Exchange pools are sources of inorganic nutrients.
• Nutrients cycle among the biotic communities of an ecosystem.
The Water Cycle
• The reservoir of the water cycle is freshwater that evaporates from the ocean.
• Water that falls on land enters the ground, surface waters, or aquifer and evaporates again.
• All water returns to the ocean.
The Carbon Cycle
• The reservoirs of the carbon cycle are organic matter, limestone, and the ocean.
• The exchange pool is the atmosphere.
• Photosynthesis removes carbon dioxide from the atmosphere.
• Respiration and combustion add carbon dioxide to the atmosphere.
The Nitrogen Cycle
• The reservoir of the nitrogen cycle is the atmosphere.
• Nitrogen gas must be converted to a form usable by plants.
• Nitrogen-fixing bacteria convert nitrogen gas to ammonium, a form producers can use.
• Nitrifying bacteria convert ammonium to nitrate.
• Denitrifying bacteria convert nitrate back to nitrogen gas.
The Phosphorus Cycle
• The reservoir of the phosphorus cycle is ocean sediments.
• Phosphate in ocean sediments becomes available through geological upheaval, which exposes sedimentary rocks to weathering.
• Weathering slowly makes phosphate available to the biotic community.
• Phosphate is a limiting nutrient in ecosystems.
Chapter 24 – Human Population, Planetary Resources, and Conservation
24.1 Human Population Growth
• Populations have a biotic potential for increase in size.
• Biotic potential is normally held in check by environmental resistance.
• Population size usually levels off at carrying capacity.
The MDCs Versus the LDCs
• The MDCs have a 0.1% growth rate since 1950
• The LDC growth rate is presently 1.6% after peaking at 2.5% in the 1960s. Age-structure diagrams can be used to predict population growth.
• MDCs are approaching a stable population size.
• LDC populations will continue to increase in size.
24.2 Human Use of Resources and Pollution
Five resources are maximally used by humans:
• Land
• Water
• Food
• Energy
• Minerals
Resources are either renewable or nonrenewable.
• Nonrenewable resources are not replenished and are limited in quantity.
• Renewable resources are replenished but still are limited in quantity.
Land
• Human activities, such as habitation, farming, and mining, contribute to erosion, pollution, desertification, deforestation, and loss of biodiversity.
Water
Industry and agriculture use most of the freshwater supply. Water supplies are increased by damming rivers and drawing from aquifers. As aquifers are depleted, subsidence, sinkhole formation, and saltwater intrusion can occur. If used by industries, water conservation methods could cut world water consumption by half.
Food
Food comes from growing crops, raising animals, and fishing.
• Modern farming methods increase the food supply, but some methods harm the land, pollute water, and consume fossil fuels excessively.
• Genetically engineered plants increase the food supply and reduce the need for chemicals.
• Raising livestock contributes to water pollution and uses fossil fuel energy.
• The increased number and high efficiency of fishing boats have caused the world fish catch to decline.
Energy
Fossil fuels are nonrenewable sources. Burning fossil fuels and burning to clear land for farming cause pollutants and gases to enter the air.
• Greenhouse gases include CO2 and other gases. Greenhouse gases cause global warming because solar radiation can pass through, but infrared heat cannot escape back into space.
• Renewable resources include hydropower, geothermal, wind and solar power.
Minerals
Minerals are nonrenewable resources that can be mined. These raw materials include sand, gravel, phosphate, and metals. Mining causes destruction of the land by erosion, loss of vegetation, and toxic runoff into bodies of water. Some metals are dangerous to health. Land ruined by mining can take years to recover.
Hazardous wastes – Billions of tons of solid waste are discarded on land and in water.
• Heavy metals
• Synthetic organic chemicals include chlorofluorocarbons, which are involved in the production of plastic, pesticides, herbicides, and other products.
• Ozone shield destruction is associated with CFCs
• Other synthetic organic chemicals enter the aquatic food chain, where the toxins become more concentrated.
24.3 Biodiversity
Biodiversity is the variety of life on Earth. The five major causes of biodiversity loss and extinction are
• Habitat loss
• Introduction of alien species
• Pollution
• Overexploitation of plant and animals, and
• Disease
Direct Value of Biodiversity
Direct values of biodiversity are:
• Medicinal value
• Agricultural value
• Consumptive use values
Indirect Value of Biodiversity
Biodiversity in ecosystems contributes to:
• Waste disposal
• Freshwater provision through the water biogeochemical cycle.
• Prevention of soil erosion, which occurs naturally in intact ecosystems
• Function of biogeochemical cycles
• Climate regulation
• ecotourism
24.4 Working Toward a Sustainable Society
A sustainable society would use only renewable energy sources, would reuse heat and waste materials, and would recycle almost everything. It would also provide the same goods and services presently provided and would preserve biodiversity.
Embryonic and Fetal Development Online Lab Write-Up
Human Demographics Online Lab Write-Up
1. My high fertility rate country is Sudan, with a fertility rate of 6.30 children.
2. My low fertility rate country is Norway, with a fertility rate of 1.80 children.
3. High fertility rates mean that there are more young people in a country than there are old people. This is because each couple is having an average ( in Sudan) of 6.3 children. When you do the math, that is a lot more children than adults. This also indicates that the population will experience greater growth. In fact, when compared to the world, Sudan's population will approximatly quadruple by the year 2050.
4. If a country has a low fertility rate, it means that as people die, there are less young people to grow the population. In fact, with Norway being used as the example, the population will hardly increase by the year 2050.
5. Some things that come to mind when I think of less young people:
- slow, old, no one to teach, no one to learn, lack of progress, no inspiration, decay, decline, less laughter, safe, more money, but nothing to spend it on.
Some things that come to mind when I think of too many young people:
- fast, inexperience, not enough teachers, progressive but unwise, dreams, fun, more crime, risk, no balance.
Lab Project Write-Up – Interaction with other species
Ethical Issue Essay
Reflection on course work – self evaluation
I am disappointed with the way I am ending the semester. I feel very rushed to complete all of my classes, and I wish I would have organized deadlines for myself better. That is what I have struggled with the most in this class. The other classes had more deadlines established by the teacher, so they seemed to always come first, which leaves me scrambling to complete my work for this class. This has been a good lessons for self-discipline (hopefully I can figure out this skill before next semester!) I do have to say though, that I have learned a lot, and I really enjoyed most of the work.
Chapter 16 – Reproductive System
16.1 Human Life Cycle
16.2 Male Reproductive System
16.3 Female Reproductive System
16.4 Female Hormone Levels
16.5 Control of Reproduction
16.6 Sexually Transmitted Diseases
Chapter 17 – Development and Aging
17.1 Fertilization
17.2 Pre-Embryonic and Embryonic Development
17.3 Fetal Development
17.4 Pregnancy and Birth
17.5 Development After Birth
Major Topic II: Human Landscapes
Chapter 22 – Human Evolution
22.1 Origin of Life
22.2 Biological Evolution
22.3 Classification of Humans
22.4 Evolution of Hominids
22.5 Evolution of Humans
Chapter 23 – Global Ecology and Human Interferences
23.1 The Nature of Ecosystems
23.2 Energy Flow
23.3 Global Biogeochemical Cycles
Chapter 24 – Human Population, Planetary Resources, and Conservation
24.1 Human Population Growth
24.2 Human Use of Resources and Pollution
24.3 Biodiversity
24.4 Working Toward a Sustainable Society
Embryonic and Fetal Development Online Lab Write-Up
Human Demographics Online Lab Write-Up
Lab Project Write-Up – Interaction with other species
Ethical Issue Essay
Reflection on course work – self evaluation
Major Topic I: Reproduction
Chapter 16 – Reproductive System
16.1 Human Life Cycle
The life cycle of higher organisms requires two types of cell division: mitosis and meiosis.
• Mitosis: growth and repair of tissues.
• Meiosis: gamete production.
16.2 Male Reproductive System
The external genital of males are:
• The penis which is used for sexual intercourse
• The scrotum which contains the testes – Spermatogenesis, occurring in seminiferous tubules of the testes, produces sperm.
• Mature sperm are stored in the epididymides
• Sperm pass from the vasa deferentia to the urethra
• The seminal vesicles, prostate gland, and bulbourethral glands add gluids by secretion to sperm
• Sperm and secretions are called semen or seminal fluid.
Orgasm in males results in ejaculation of semen from the penis.
Hormonal Regulation in Males:
• Hormonal regulation, involving secretions from the hypothalamus, the anterior pituitary, and the testes, maintains a fairly constant level of testosterone.
• FSH from the anterior pituitary promotes spermatogenesis.
• LH from the anterior pituitary promotes testosterone production by interstitial cells.
16.3 Female Reproductive System
Oogenesis occurring within the ovaries typically produces one mature follicle each month.
• This follicle balloons out of the ovary and bursts, releasing an egg that enters an oviduct.
• The oviducts lead to the uterus, where implantation and development occur.
• The female external genital area includes the vaginal opening, the clitoris, the labia minora, and the labia majora.
• The vagina is the organ of sexual intercourse and the birth canal.
• Orgasm in females culminates in uterine and oviduct contractions.
16.4 Female Hormone Levels
Ovarian Cycle: Nonpregnant
• The ovarian cycle is under the hormonal control of the hypothalamus and the anterior pituitary.
• During the cycle’s first half, FSH from the anterior pituitary causes maturation of a follicle that secretes estrogen and some progesterone.
• After ovulation and during the cycle’s second half, LH from the anterior pituitary converts the follicle into the corpus luteum.
• The corpus luteum secretes progesterone and some estrogen.
Uterine Cycle: Nonpregnant
• Estrogen and progesterone regulate the unterine cycle.
• Estrogen causes the endometrium to rebuild.
• Ovulation usually occurs on day 14 of a 28 day cycle.
• Progesterone produced by the corpus luteum causes the endometrium to thicken and become secretory.
• A low level of hormones causes the endometrium to break down as menstruation occurs.
Fertilization and Pregnancy
• If fertilization takes place, the embryo implants itself in the thickened endometrium.
• The corpus luteum is maintained because of HCG production by the placenta, and therefore, progesterone production does not cease.
• Menstruation usually does not occur during pregnancy.
16.5 Control of Reproduction
Numerous birth control methods and devices are available.
• A few of these are the birth control pill, diaphragm, and condom.
• Effectiveness varies.
• Assisted reproductive technologies may help infertile couples to have children. Some of these technologies are:
o Artificial insemination by donor (AID)
o In vitro fertilization (IVF)
o Gamete intrafallopian transfer (GIFT)
o Intracytoplasmic sperm injection (ICSI)
16.6 Sexually Transmitted Diseases
STDs are caused by viruses, bacteria, protists, fungi, and animals.
STDs Caused by Viruses:
• AIDS is caused by HIV (human immunodeficiency virus).
• Genital warts are caused by human papillomaviruses; these viruses cause warts or lesions on genitals and are associated with certain cancers.
• Genital herpes is caused by herpes simplex virus type 2: causes blisters on genitals.
• Hepatitis is cause by hepatitis viruses A, B, C, D, E, and G. A and E are usually acquired from contaminated water; hepatitis B and C from blood borne transmission; and B, D, and G are sexually transmitted.
STDs Caused by Bacteria
• Chlamydia is caused by Chlamydia trachomatis: PID can result.
• Gonorrhea is caused by Neisseria gonorrhoeae; PID can result.
• Syphilis is cause by Treponema pallidum. It has three stages, with the third stage resulting in death.
Two Other Infections
• Bacterial vaginosis is caused by Gardnerella vaginalis.
• Trichomoniasis is an overgrowth of Candida albicans.
Chapter 17 – Development and Aging
17.1 Fertilization
The acrosome of a sperm releases enzymes that digest a pathway for the sperm through the zona pellucida. The sperm nucleus enters the egg and fuses with the egg nucleus.
17.2 Pre-Embryonic and Embryonic Development
• Cleavage, growth, and morphogenesis, and differentiation are the processes of development.
• The extraembryonic membranes (chorion, allantois, yolk sac, and amnion) function in internal development.
17.3 Fetal Development
• At the end of the embryonic period, all organ systems are established, and there is a mature and functioning placenta. The umbilical arteries and umbilical vein take blood to and from the placenta, where exchanges take place.
• Exchanges supply the fetus with oxygen and nutrients and rid the fetus of carbon dioxide and wastes.
• The venous duct joins the umbilical vein to the inferior vena cava.
• The oval duct and arterial duct allow the blood to pass through the heart without going to the lungs. Fetal development extends from the third through the ninth months.
• During the third and fourth months, the skeleton is becoming ossified.
• The sex of the fetus becomes distinguishable. If an SRY gene is present, testes and male genitals develop. Otherwise, ovaries and female genitals develop.
• During the fifth months, the fetus continues to grow and to gain weight.
17.4 Pregnancy and Birth
Major changes take place in the mother’s body during pregnancy.
• Weight gain occurs as the uterus occupies most of the abdominal cavity.
• Many complaints, such as constipation, heartburn, darkening of certain skin areas, and pregnancy-induced diabetes, are due to the presence of placental hormones.
Birth
• A positive feedback mechanism that involves uterine contractions and oxytocin explain the onset and continuation of labor.
• During stage 1 of birth, the cervix dilates.
• During stage 2, the child is born.
• During stage 3, the afterbirth is expelled.
17.5 Development After Birth
Development after birth consists of infancy, childhood, adolescence, and adulthood.
• Aging encompasses progressive changes from about age 20 on that contribute to an increased risk of infirmity, disease, and death.
Hypothesis on Aging
• Aging by have a genetic basis.
• Aging may be due to changes that affect the whole body
• Aging may be due to extrinsic factors like diet and exercise.
Effect of Age on Body Systems
• Deterioration of organ systems can possibly be prevented or reduced in part by utilizing good health habits.
Major Topic II: Human Landscapes
Chapter 22 – Human Evolution
22.1 Origin of Life
A chemical evolution could have produced the protocell.
• Using an outside energy source, small organic molecules were produced by reactions between early Earth’s atmospheric gases.
• Macromolecules evolved and interacted.
• The RNA-first hypothesis – only macromolecule RNA was needed for the first cell(s).
• The protein-first hypothesis – amino acids join to form polypeptides when exposed to dry heat.
• The protocell, a heterotrophic fermenter, lived on preformed organic molecules in the ocean.
The protocell eventually became a true cell once it had genes composed of DNA and could reproduce.
22.2 Biological Evolution
Biological evolution explains both the unity and diversity of life.
• Descent from a common ancestor explains the unity of living things.
• Adaptation to different environments explains the great diversity of living things.
• Fossil evidence supports evolution. The fossil record gives us the history of life in general and allows us to trace the descent of a particular group.
Darwin discovered much evidence for common descent.
• Biological evidence – The distribution of organisms on Earth is explainable by assuming that organisms evolved in one locale.
• Anatomical evidence – The common anatomies and development of a group of organisms are explainable by descent from a common ancestor.
• Biochemical evidence – All organisms have similar biochemical molecules.
Darwin developed a mechanism for adaptation known as natural selection.
The result of natural selection is a population adapted to its local environment.
22.3 Classification of Humans
The classification of humans can be used to trace their ancestry.
• Humans are primates
• A primate evolutionary tree shows that humans share a common ancestor with African apes.
22.4 Evolution of Hominids
• The first hominid most likely lived about 6-7 MYA.
• Certain features identify fossil hominids.
• Ardipithecines were most likely hominids
Evolution of Australopithecines
The evolutionary tree of hominids resembles a bush (not a straight line of fossils leading to modern humans).
• Australopithecines lived about 3 MYA.
• They could walk erect, but they had a small brain.
• This testifies to a mosaic evolution for humans (not all advanced features evolved at the same time).
22.5 Evolution of Humans
Fossils are classified as Homo with regard to their brain size (over 600cm3), jaws and teeth, and evidence of tool use.
• H.habilis made and used tools.
• H.erectus was the first Homo to have a brain size of more than 1000 cm3.
• H.erectus migrated from Africa into Europe and Asia.
• H. erectus used fire and may have been big-game hunters.
Evolution of Modern Humans
Two hypotheses of modern human evolution are being tested.
• The multiregional continuity hypothesis suggests that modern humans evolved separately in Europe, Africa, and Asia.
• The out-of-Africa hypothesis says that H.sapiens evolved in Africa but then migrated to Asia and Europe.
Neanderthals and Cro-Magnons
• The Neanderthals were already living in Europe and Asia before modern humans arrived.
• They had a culture, but did not have the physical traits of modern humans.
• Cro-Magnons are the oldest fossil to be designated H.sapiens. Their tools were sophisticated, and they had a culture.
Chapter 23 – Global Ecology and Human Interferences.
23.1 The Nature of Ecosystems
Ecology is the study of the interactions of organisms with each other and with the physical environment.
• Organisms interact with the physical and chemical environment, and the result is an ecosystem.
• Terrestrial ecosystems are forests, grasslands, and deserts, which includes the tundra.
• Aquatic ecosystems are either salt water or freshwater.
Biotic Components of an Ecosystem
• In a community, each population has a habitat and a niche.
• Autotrophs produce organic nutrients for themselves and others from inorganic nutrients and an outside energy source.
• Heterotrophs consume organic nutrients.
• Consumers are herbivores, carnivores, and omnivores.
• Decomposers feed on detritus, releasing inorganic substances back into the ecosystem.
Energy Flow and Chemical Cycling
• Ecosystems are characterized by energy flow and chemical cycling.
• Energy flows through the populations of an ecosystem.
• Chemical cycle within and among ecosystems.
23.2 Energy Flow
Various interconnecting paths of energy flow are called food web.
• A food web is a diagram showing how carious organisms are connected by eating relationships.
• Grazing food webs begin with vegetation eaten by a herbivore that becomes food for a carnivore.
• Detrital food webs begin with detritus, food for decomposers and for detritivores.
• Members of detrital food webs can be eaten by above ground carnivores, joining the two food webs.
Trophic Levels
• A trophic level is all the organisms that feed at a particular link in a food chain.
• Ecological pyramids illustrate that biomass and energy content decrease from one trophic level to the next because of energy loss.
23.3 Global Biogeochemical Cycles
Chemicals circulate through ecosystems via biogeochemical cycles, pathways involving both biotic and geological components. Biogeochemical cycles:
• Can be gaseous or sedimentary.
• Have reservoirs that contain inorganic nutrients available to living things on a limited basis.
• Exchange pools are sources of inorganic nutrients.
• Nutrients cycle among the biotic communities of an ecosystem.
The Water Cycle
• The reservoir of the water cycle is freshwater that evaporates from the ocean.
• Water that falls on land enters the ground, surface waters, or aquifer and evaporates again.
• All water returns to the ocean.
The Carbon Cycle
• The reservoirs of the carbon cycle are organic matter, limestone, and the ocean.
• The exchange pool is the atmosphere.
• Photosynthesis removes carbon dioxide from the atmosphere.
• Respiration and combustion add carbon dioxide to the atmosphere.
The Nitrogen Cycle
• The reservoir of the nitrogen cycle is the atmosphere.
• Nitrogen gas must be converted to a form usable by plants.
• Nitrogen-fixing bacteria convert nitrogen gas to ammonium, a form producers can use.
• Nitrifying bacteria convert ammonium to nitrate.
• Denitrifying bacteria convert nitrate back to nitrogen gas.
The Phosphorus Cycle
• The reservoir of the phosphorus cycle is ocean sediments.
• Phosphate in ocean sediments becomes available through geological upheaval, which exposes sedimentary rocks to weathering.
• Weathering slowly makes phosphate available to the biotic community.
• Phosphate is a limiting nutrient in ecosystems.
Chapter 24 – Human Population, Planetary Resources, and Conservation
24.1 Human Population Growth
• Populations have a biotic potential for increase in size.
• Biotic potential is normally held in check by environmental resistance.
• Population size usually levels off at carrying capacity.
The MDCs Versus the LDCs
• The MDCs have a 0.1% growth rate since 1950
• The LDC growth rate is presently 1.6% after peaking at 2.5% in the 1960s. Age-structure diagrams can be used to predict population growth.
• MDCs are approaching a stable population size.
• LDC populations will continue to increase in size.
24.2 Human Use of Resources and Pollution
Five resources are maximally used by humans:
• Land
• Water
• Food
• Energy
• Minerals
Resources are either renewable or nonrenewable.
• Nonrenewable resources are not replenished and are limited in quantity.
• Renewable resources are replenished but still are limited in quantity.
Land
• Human activities, such as habitation, farming, and mining, contribute to erosion, pollution, desertification, deforestation, and loss of biodiversity.
Water
Industry and agriculture use most of the freshwater supply. Water supplies are increased by damming rivers and drawing from aquifers. As aquifers are depleted, subsidence, sinkhole formation, and saltwater intrusion can occur. If used by industries, water conservation methods could cut world water consumption by half.
Food
Food comes from growing crops, raising animals, and fishing.
• Modern farming methods increase the food supply, but some methods harm the land, pollute water, and consume fossil fuels excessively.
• Genetically engineered plants increase the food supply and reduce the need for chemicals.
• Raising livestock contributes to water pollution and uses fossil fuel energy.
• The increased number and high efficiency of fishing boats have caused the world fish catch to decline.
Energy
Fossil fuels are nonrenewable sources. Burning fossil fuels and burning to clear land for farming cause pollutants and gases to enter the air.
• Greenhouse gases include CO2 and other gases. Greenhouse gases cause global warming because solar radiation can pass through, but infrared heat cannot escape back into space.
• Renewable resources include hydropower, geothermal, wind and solar power.
Minerals
Minerals are nonrenewable resources that can be mined. These raw materials include sand, gravel, phosphate, and metals. Mining causes destruction of the land by erosion, loss of vegetation, and toxic runoff into bodies of water. Some metals are dangerous to health. Land ruined by mining can take years to recover.
Hazardous wastes – Billions of tons of solid waste are discarded on land and in water.
• Heavy metals
• Synthetic organic chemicals include chlorofluorocarbons, which are involved in the production of plastic, pesticides, herbicides, and other products.
• Ozone shield destruction is associated with CFCs
• Other synthetic organic chemicals enter the aquatic food chain, where the toxins become more concentrated.
24.3 Biodiversity
Biodiversity is the variety of life on Earth. The five major causes of biodiversity loss and extinction are
• Habitat loss
• Introduction of alien species
• Pollution
• Overexploitation of plant and animals, and
• Disease
Direct Value of Biodiversity
Direct values of biodiversity are:
• Medicinal value
• Agricultural value
• Consumptive use values
Indirect Value of Biodiversity
Biodiversity in ecosystems contributes to:
• Waste disposal
• Freshwater provision through the water biogeochemical cycle.
• Prevention of soil erosion, which occurs naturally in intact ecosystems
• Function of biogeochemical cycles
• Climate regulation
• ecotourism
24.4 Working Toward a Sustainable Society
A sustainable society would use only renewable energy sources, would reuse heat and waste materials, and would recycle almost everything. It would also provide the same goods and services presently provided and would preserve biodiversity.
Embryonic and Fetal Development Online Lab Write-Up
Human Demographics Online Lab Write-Up
1. My high fertility rate country is Sudan, with a fertility rate of 6.30 children.
2. My low fertility rate country is Norway, with a fertility rate of 1.80 children.
3. High fertility rates mean that there are more young people in a country than there are old people. This is because each couple is having an average ( in Sudan) of 6.3 children. When you do the math, that is a lot more children than adults. This also indicates that the population will experience greater growth. In fact, when compared to the world, Sudan's population will approximatly quadruple by the year 2050.
4. If a country has a low fertility rate, it means that as people die, there are less young people to grow the population. In fact, with Norway being used as the example, the population will hardly increase by the year 2050.
5. Some things that come to mind when I think of less young people:
- slow, old, no one to teach, no one to learn, lack of progress, no inspiration, decay, decline, less laughter, safe, more money, but nothing to spend it on.
Some things that come to mind when I think of too many young people:
- fast, inexperience, not enough teachers, progressive but unwise, dreams, fun, more crime, risk, no balance.
Lab Project Write-Up – Interaction with other species
Ethical Issue Essay
Reflection on course work – self evaluation
I am disappointed with the way I am ending the semester. I feel very rushed to complete all of my classes, and I wish I would have organized deadlines for myself better. That is what I have struggled with the most in this class. The other classes had more deadlines established by the teacher, so they seemed to always come first, which leaves me scrambling to complete my work for this class. This has been a good lessons for self-discipline (hopefully I can figure out this skill before next semester!) I do have to say though, that I have learned a lot, and I really enjoyed most of the work.
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