Saturday, May 17, 2008

Self and Unit Evaluation

Was looking for my grades and remembered that I did not post this eval. I guess I thought I had done it, since I filled out the class evaluation for Yavapai College. So whether or not it's worth anything, I thought I would post it anyway.

What were the three aspects of the assignments I've submitted that I am most proud of?
I felt as though I learned valuable lessons. Initially, I was dissapointed that I had to learn about the integration of species, etc., and not just human systems, but now I have a better appreciation of the earth's resources than before. This will definately impact the way I choose products.
I do feel as though the assignments were complete. Except I almost forgot to submit this eval . . .
I enjoyed finding the photos and felt like they displayed my points and sometimes off-humor . . .
2. What two aspects of my submitted assignments do I believe could have used some improvement?
I don't feel as though there was much room for improvement. I worked pretty hard on these assignments.
3. What do I believe my overall grade should be for this unit?
Again, hoping for an A.
4. How could I perform better in the next unit?
We're done!!! Next unit is summer break and I hope to excell at that as well.

REGARDING THE UNIT (adapted from Stephen Brookfield, University of St. Thomas "Critical Incident Questionnaire")
At what moment during this unit did you feel most engaged with the course?
Began to enjoy the compendiums better. I thoroughly enjoy the online labs. They create an atmosphere of learning that's new and fun.

At what moment unit did you feel most distanced from the course?

Early in the course, I hated working on those tedious compendiums. I have come to enjoy picking out information and finding correlating information and pics.
What action that anyone (teacher or student) took during this unit that find most affirming and helpful?
Mr. Frolich is always encouraging. Now whenever I hear any one say, "have fun" I shall think of him. He always puts that at the end of his instructions.

What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?
What about this unit surprised you the most? (This could be something about your own reactions to the course, something that someone did, or anything else that occurs to you.)
What is surprising is that I now feel more aware of my environment and have an fresh awareness of personal responsibility regarding it's upkeep.
Thank you, Mr. Frolich for this enlightening course.

Sunday, May 11, 2008

Online Lab: Human Population Demographics


Below is a depiction of the world's population growth from 1990 - 2050 resting above the expected growth pattern for Ethiopia.

Ethiopia is the high fertility rate depicted at 6.9. Because the fertility rate is so high, the population has a large percentage of children, who will be entering their reproductive stage. This means that the population will continue to grow exponentially because parents will continue to live while their children are growing and reproducing themselves. The life expectancy is only 51.8 years, approximately 17 years lower than the world's average. This will ease the population growth some, but not enought to stop or reverse the pattern already established.

Below is a depiction of the world's population growth with an example of Japan's growth shown beneath it.

Japan's fertility rate is low, 1.6%. As people choose to have fewer children, the number of middle-aged people begins to outnumber their replacements. This poses a larger economic responsibility on younger people. As the middle-aged population enters retirement, there will be a shift in the job market as positions will have no one to fill them. Medicare and social security in the USA (our rate is similar) will be straining to support the elderly, if it can at all.

How will this affect attitudes in situations of greater populations of children?

Perhaps, parents will feel pressured to limit their offspring. In dire circumstances, such as in China, abortions may be forced upon couples to maintain "equilibrium". Maybe parents will have to choose which of their children will be fed or be schooled because of limited resources. Children are needed in some poorer regions to help support the family and that is why many of these MDCs continue to have large families. Hopefully, education will prevail and options more suitable to better quality of life will help parents decide and take control of their own family's future.

In populations where the middle-aged and elderly are prevalent, quality of life may be interpreted by others and early termination may be considered to be an option. Remember "Soylent Green?" Instead of representing wisdom, the elderly will be a burden, perceived as unproductive and a drain on medical systems. I would like to see the middle-aged working later into their golden years, contributing more in the workplace and volunteering to fill positions needed in their community. I think that organizations like SCORE (a resource of retired business people who volunteer to advise people interested in owning a business) are a valuable commodity. Efforts should be made to avoid the polarization of the young vs the old.

In either one of these circumstances, it is unfortunate that people (very young or very old) may be perceived as dispensable (or do I mean disposable?).

If we step back and assess every situation we find ourselves in, we should be innovative enough to overcome the difficulties that arise. A few dedicated people to get the word out and some resources to help those in need can begin to make the impact for change.

I want to thank you for opening my eyes. I hope I am able to make some of the changes needed to help change the direction we're heading.

Foster grandparents at work . . .

Essay: Who Should Reproduce?

Who Should Reproduce?

Some folks are asking, should we reproduce at all? Given the negative impact humankind has had on the environment, the conclusion drawn by a wary few, is that we should remove ourselves from earth all together.
With all the talk about population growth, we tend to think that less developed nations (LDCs) are the greatest offenders. Their population growth is still 16 times the average growth of more developed nations (MDCs). MDC’s have a global population growth of 0.1% (the USA has 0.6%) and LDCs growth rate is 1.6%.

Population Rates of LDCs and MDCs . . .
Collectively, we are adding 78 million people annually to the world’s population. However, when we consider sustainability or carrying capacity, then we must also look at the resources each population consumes.
The organization represented below allows you to enter your lifestyle and consumptive habits. I consider myself to be an average consumer. If everyone on earth lived as I do, we would need the resources of 5.3 planets. As we take the quiz, there are suggestions as to how we can modify our choices to better respect the environment and its limitations.

Results of environmental footprint quiz . . .

Obviously, everyone doesn’t have this lifestyle. So we can conclude that the less-developed, overly-populated countries are using far less than we are. In fact, Mr. Frolich states from the Human Biology site that a typical US child will use enough resources to support 300 children in Ethiopia. I have to ask, support them adequately? Because they use less, doesn’t mean that it is optimal. Diseases and health issues arise from squalor.

‘Who is impacting the environment’ seems to be the pivotal question. MDCs are greater consumers, but LDCs are already living in sub-standard, unhealthy conditions and their populations are growing at a far greater rate. They, too, have negatively impacted their environment.
Who should reproduce? Couples who want children and can provide a stable and loving environment for their children. These issues will not leave us; rather they will challenge us to consume smartly, recycle and reuse, to educate fellow humans and pull together lest we all fall apart. I cannot embrace a mentality similar to Hitler’s or China’s in cleansing or reducing the burden of the human population. I believe that education is our best tool. If women were aware of their options for birth control and the tools needed for such were available, we would see a drastic reduction in birth rate (I should mention that men need education as well). If the common man were aware of the impact of his choices, maybe he would make different ones.
Education and understanding may stir up in us the desire to make a few sacrifices, chose a little differently, and live in better harmony in the diverse biosphere created for us.
Mankind . . .

Saturday, May 10, 2008

Species Interaction Project

Lab 4 Project: List of Species

My day has just begun. After sleeping with a mattress full of dust mites . . .
Dermatophagoides farina – (dust mites, bed bugs)
Living in a commensalistic relationship, we acknowledge that these mites must dine on something, so my dead skin provides endless banquets and literally costs me nothing. I am not allergic to them or their excrements. According to Environment Health and Safety, there may be 100,000 to 10 million mites inside my mattress. Ten percent of the weight of my pillow at 2 years old may actually be dead mites and their droppings. These are not domesticated, but rather wild organisms. If humans had their way, these would be eliminated because it’s just gross to think about sleeping with these bugs. Pleasant dreams . . .

The dust mite . . .

Back to the story: I got up from my crowded bed and proceeded to the bathroom. Washing my hands of e coli . . .
Escherichia coli – (e-coli) A bacterium commonly found in the lower intestines which has several strains. Harmless strains actually produce vitamin K and will prevent pathogenic organisms from becoming established in the bowel. It is the harmful strain, serotype O157:H7, which can cause serious illness and death. For the harmless strain, the relationship is mutualistic; both benefit from the relationship. The harmful strain is parasitic in nature, even potentially leading to the death of the host and subsequently, the bacteria. The future for this relationship will continue to be a) for the harmless strain, mutually beneficial and b) for serotype 0157:H7, limited due to diligence and handwashing.

I turned on the coffee machine and proceeded to listen to it grind the beans . . .
Coffea arabica – (coffee) A tropical plant that produces beans from which a very popular, caffeinated beverage is made. This relationship is beneficial to humans in a very major way. Even the people who don’t drink it benefit from the perkiness and alertness of those who do. This is a predatoristic relationship and would not benefit this plant, except that we want this relationship to thrive, so we will plant ample replacements. Coffee plants will survive forever, at least the flavorful ones will.

Coffee Plant . . .

After the steamy, hot, aromatic coffee is done pouring into my cup, I pour in a generous portion of soy milk . . .
Glycine L. max – (soy) Native to east Asia, this plant produces an annual crop of beans which are, by weight, 40% protein and 20% fat. Most of the soy crop is used as animal feed and a relatively small portion is consumed by humans. This relationship is very similar to our coffee relationship. We harvest the beans and plant replacements. We are the predators and the propagators. This relationship will continue and perhaps soy will flourish because of its excellent nutritional content and is a cheap alternative to meat. It is uncertain whether the original plant or the genetically altered plant will prevail. In any event, I would certainly label soy a domesticated species.

Now that I am sufficiently perked, I look at the dog . . .

Buster . . . (had his nose in flour)

Canis lupus familiaris – (domestic dog) Mine is a black labrador/mix. He is hungry and wants to go outside. I get some dog food and fill his other bowl with water and begin to wonder who is the master. He is appreciative, so I feel OK with my servitude. This is a symbiotic relationship. He gives companionship and some protection if he barks (probably while hiding under a table or behind me) and I provide shelter, food and companionship. This relationship between dog and humans has evolved into manipulation of the species by selective breeding and encouraging different traits to accommodate our needs/desires. Dogs have served humans for an untold number of centuries and there are many instances where they are, indeed, man’s best friend. The domestic dog is definitely a domesticated species.

So the dog is fed and happy, and it’s time to get ready for work. I wash my face and brush my teeth . . .
Streptococcus mutans and anaerobes - Biofilm (dental plaque) is a film of microorganisms that builds up on teeth. This film is composed mostly of bacteria. This is a commensalistic relationship and the bacteria is not domesticated. The bacteria is harmless unless it remains on the teeth. The film thickens and the organisms nearest the tooth convert to anaerobic respiration which produces acids that demineralize the surface of the teeth. I’ve not read that bacterium have become resistive to brushing and flossing so it’s future in today’s society will be limited in those who do regular mouth hygiene. As long as there are mouths with teeth and food (particularly sugar) to be eaten, there will be biofilm. If man had his way, there would be a vaccination that would eliminate the bacteria altogether. It’s future with mankind is uncertain.

After reading the labels on the beauty products, I find one with English words, it is Pycnogenol wrinkle cream . . .
Pinus pinaster (French Maritime Pine) – The bark of this tree is used commonly in alternative medicine to reduce inflammation. It is taken orally or topically to achieve stated goal. Recent studies also state that Pycnogenol slows glucose absorption 190 times more potently than prescription medication and also has many other health benefits. I also take this orally for joint pain, which I haven’t had for years while on it. These trees grow along the coast of southwest France.

French Maritime Pine Trees

Because of the preponderance of research being done on Pycnogenol, I am not able to determine if there are groves of this tree for mass production or if raw landscapes are being harvested. I will call these wild. Given the huge impact this plant has made on various health issues, I would hope that these trees are being replaced.

Having sufficiently creamed, colored and plastered my face, I proceed to dressing. The scrubs are 100% cotton . . .
Gossypium – (cotton) A shrub native to the tropical and subtropical regions, cotton is the most common textile today. Cotton has been genetically modified (GM)to resist boll weevils. Twenty percent of the worldwide area of planted cotton is GM. 75% of US cotton was GM in 2003. This is a commensal relationship that will not eliminate the cotton plant. I believe if you can call plants domesticated this would be one. It is perennial and will continue to grow after harvesting. What may eliminate the original plant is genetic engineering and the replacement of original, organic cotton with such. Of interest, my deodorant is without aluminum and uses cotton to help absorb perspiration.

Cotton plant . . .

My work shoes are leather . . .

Domesticated ungulates, a member of the subfamily Bovinae – (cow)I am assuming that the leather came from cows. The world cattle population is estimated at 1.3 billion. They have been domesticated since the Neolithic age. I think this relationship is both predatistic and mutualistic, depending on the use of the cattle. “A 400-page United Nations report from the Food and Agriculture Organization (FAO) states that cattle farming is "responsible for 18% of greenhouse gases."The production of cattle to feed and clothe humans stresses ecosystems around the world, and is assessed to be one of the top three environmental problems in the world on a local to global scale.” "Cattle." Wikipedia, The Free Encyclopedia. 28 Apr 2008, 19:42 UTC. Wikimedia Foundation, Inc. 30 Apr 2008 <>.
Cattle have been altered to best serve our perceived needs and will continue to be subjected to the changing desires of man.

Well, shoes are on and the face is presentable. It’s time to head towards work. It’s a beautiful day and the birds are singing . . .
Passeriformes emberizidae (warblers) – I don’t know the name of the birds I heard, but these sound as though they make noise and they’re from our local bird guide. Birds are often a mixed blessing. They’re messy and noisy to some, or they are music makers to others. Birds are kept as pets and have been bred for certain traits and they are also wild. Wild collisions with aircraft cost US civil aviation more than $470 million annually. Wild birds cost property owners millions of dollars annually for damage to homes and landscaping. Bird attacks on people and bird droppings also pose health hazards. Attempts are being made to find ways of coexisting with these wild birds. I’m sure populations of birds are being affected by reduced natural habitats caused by urban developments. Their future is uncertain because attempts will be made to accommodate their needs. Our relationship with wild birds is symbiotic – we benefit from their music and perhaps some insect/worm control and they benefit from bird feeders and baths.

Pine warbler . . .

I pause to admire the blossoms on the pear tree . . .
Pyrus communis sativa (pear) – A common fruit that grows on trees. It is sweet and can be eaten raw or cooked. We have pear orchids for mass production. This is a commensal relationship because we cultivate and maintain pear orchids to preserve production. The trees are not harmed with harvest. Pears and humans will continue to benefit from each other for a long time.

I drive to work and walk on the sidewalk to avoid trampling the grass . . .
Cynodon dactylon (Bermuda Grass) – Bermuda grass, is of probable Asian origin and was documented as an important grass in the United States by l807. It is a long-lived, warm season perennial that spreads by rhizomes, stolons, and seed. It is used in warm climates and grows well in temperatures exceeding 100 degrees F. In some areas, it is considered noxious and invasive. Bermuda grass will continue to be utilized as long as we have water to throw on our lawns. I’m sure it has been modified in some way to accommodate different areas of application. In that respect, I would have to say most of the existing Bermuda grass is probably domesticated. Our relationship is mutualistic.

Bermuda Grass . . .

After report, I administer Insulin to a patient . . .
Escherichia coli (e-coli) – Surprised to see that? The very bacteria I washed from my hands earlier today produces insulin using recumbant DNA techniques. Human DNA is “introduced” (simply stated) to the bacteria which will reproduce at an incredible rate. Prior to this technology, Porcine was the primary source for Insulin. By 2001, 95% of all insulin-dependent diabetics were using this genetically modified insulin. Well, e-coli is not a domestic species, but I would have to say the lab-contained version would probably be classified as such. I would say this is a predatoristic relationship, since the bacteria are destroyed when the insulin is removed. The future for this bacteria is very strong, even without lab-grown populations.

Another patient is given a Cranberry Capsule . . .
Vaccinium oxycoccus (cranberries) – Since the beginning of the 21st century, cranberries have enjoyed increased popularity and their nutrient content and antioxidant qualities have given them commercial status as a "superfruit". It is the main agricultural export for several states and in Canada. It is no longer wild in Scotland. Arctic, Nordic and Russian people are still harvested from the wild. Cranberries have been approved by the French government for use as an antibacterial agent for urinary tract infections. This is a mutualistic relationship, because the plants are not harmed and they are farmed to maintain their numbers. Wild plants have decreased in number because of diminishing wild lands.

Cranberry harvesting . . . Yumm!

I break for lunch and eat a peanut butter and jelly sandwich . . .
Arachis hypogaea (peanut)-The domesticated peanut has two sets of chromosomes from two different species which may have occurred in Argentina or Bolivia. The peanut was introduced to China in the 1600’s and a different species again in the 1800’s. By 2006, China was the world’s greatest producer of peanuts. This is a predatoristic relationship, since the entire plant must be removed to harvest the peanuts.

Fragaria ananassa (strawberry)-Strawberries are cultivated and harvested primarily in the northern Americas. The plants remain in the soil and will produce smaller crops each year. The soil will need to be re-seeded every 2-3 years. This is a parasitic relationship. The plants will be replanted every few years to keep production optimal. Wild strawberries will continue as long as there continues to be wild landscape to accommodate the species.

Bread . . .
Triticum T. aestivum (bread wheat) – Gobally, the second most produced food crop. This is a domesticated species whose demand is higher than the yield. There was a big push to begin using genetically modified wheat in 2005, but the plans for implementation were withdrawn. Many people have wheat allergies and 1 out of every 1-200 people have Celiac’s disease, an auto immune disorder wherein the person affected cannot tolerate the wheat’s protein. Wheat does grow in the wild, but it is now domesticated. This is a predatoristic relationship.

With the peanut butter and jelly sandwich, I drink a large, cold glass of milk . . .
Bos taurus (dairy cow) – This is a domesticated animal, that is raised to produce milk for human consumption. Cattle farming contributes 18% of all greenhouse gasses. This is a predatoristic relationship. Cattle are kept until they can no longer produce milk. Then they are destroyed and their meat is used for cheaper cuts such as hamburger.

The cow . . .

So after that nutritious lunch, I return to work. Many of the residents get calcium . . .
Crassostrea gigas (oyster) – these are marine animals, comprised of two calcified halves surrounding their soft body. This succulent body is a treat for many people. The shells are a source of Calcium Carbonate. These animals have been cultivated for over a century, but many are still wild. The relationship we have with this animal is predatoristic. Their future is promising so long as they are the ones we cultivate. Marine habitats are changing and becoming polluted, so the future of the wild oysters is uncertain.

It’s getting warmer and the bugs are starting to appear. There are huge flycatchers in the dining room . . .
Musca domestica (housefly) – one of the most widely distributed pests. Flies are capable of carrying over 100 diseases and some strains have become resistant to pesticides. Our relationship with flies is commensal, they benefit from our garbage, livestock, and pets’ refuse. Flies will probably be around forever. There’s always “food” available.

The Fly - up close and personal . . .

Well, work is done, and it’s time to pick up a few things on the way home. I pull into Frys.
My kids love bananas . . .

Musa acuminata (bananas) – cultivated throughout the tropics, they are loved and enjoyed year-round. Bananas are exported while still green to reduce damage and bruising. The majority of these are gassed with ethylene gas to make them ripen. Bananas were documented first in Asia and domestication began there. They still grow in the wild, but most bananas are cultivated. Cultivated bananas are sterile and are reproduced by cuttings. This is a mutualistic relationship because these bananas would not reproduce without us and we would not enjoy their fruit without them.

Bananas in Bloom . . .

Upon completing this project, I see that most of our relationships with the species around us are predatoristic. I wouldn’t want to be my neighbor. . .

Wednesday, May 7, 2008

Compendium: Chapters 22-24

Compendium IV: Human Landscapes Chapters 22-24

Chapter 22: Human Evolution

22.1 Origin of Life

According to the theory of evolution, the Earth is estimated to have formed over a period of 10 billion years. The solar system has been in place for 4.6 billion years. Because of the mass of Earth, it has an atmosphere. It was composed of gases that were escaping volcanoes. As the earth cooled, the water vapors in the atmosphere rained on the earth forming the oceans. It is hypothesized that gases washed into the oceans exposed to radiation became organic compounds. Stanley Miller replicated this process in an experiment in 1953.

Artists’ interpretation of the beginnings of earth:
The small organic molecules found each other and formed macromolecules. One hypothesis formulates that ribonucleic acid (RNA) was the only macromolecule was needed to progress toward life because RNA can behave as a substrate and an enzyme during processing. The second theory is called the protein-first hypothesis. Sidney Fox demonstrated that amino acids join together when exposed to heat. This may have occurred in puddles when the water evaporated. They may have formed polypeptides with catalytic properties that became microspheres in the water.
Now when two lipids are in proximity of a microsphere, they unite and form a lipid-protein membrane which is called a protocell. This heterotroph needed food, but was not able to replicate.
A true cell reproduces and needs DNA and enzymatic proteins. In the RNA-first theory, DNA would have replicated from the RNA. In the protein-first hypothesis, the some of the proteins evolved into enzymes that synthesized DNA from nucleotides. The DNA would have directed enzyme synthesis so all the enzymes would be present and then DNA could be replicated.

22.2 Biological Evolution

It is reasoned that the first cells would have been the simplest, therefore they would have been prokaryotic cells (whose DNA is not in a nucleus). From there, multiple other types of cells evolved. Biological evolution is the process whereby a species from a common ancestor changes over time by adapting. In different areas, different adaptations would have occurred and this explains the diversity we have today.
The evolutionist, Charles Darwin observed that there were three types of evidence inferring evolution from a common ancestor:
Fossils: Smaller, older fossils are generally found deeper, in lower strata. Prokaryotes and unicellular eukaryotes are the earliest ones. Fossils with characteristics from two different species are called transitional.

Strata with fossils:

Biogeography studies the placement of differing and similar plants and animals around the world. Certain species of animals can be located in one area on earth and not be found in a similar climate. This is interpreted to mean that the species evolved in that area and is therefore unique to it. Anatomical evidence shows similarities in anatomy between species which infers that they share a common ancestor. Biochemical demonstrates that all living things share similar molecules. DNA sequences also display a remarkable similarity between species.
Darwin described adaptation as a process whereby the stronger and healthier traits are passed on to the next generation. Weaker or less capable members were not able to survive or were not mated.

22.3 Classification of Humans

DNA data is most currently used to trace our roots. Mitochondrial DNA is used to determine the timing of evolutionary events because it changes frequently.
Primates are divided into 2 groups: Prosimians, which include lemurs, and anthropoids which includes monkeys, apes, and humans. Monkeys and apes have opposable thumbs and toes. Humans have opposable thumbs. The primates also have forward focusing eyes with stereoscopic vision (depth perception) to assist in judging placement of limbs while swinging around. Humans and apes also have colored vision. Primates have larger more intricate brains. The human brain is so large, it is wrinkled to increase area. Since the mode of movement in primates is to move from limb to limb, they have a reduced reproductive rate.
Genomes between humans and apes are 99% similar, but many differences exist between them. Speech, hearing and smell are dissimilar and also skeletal differences enable the human to walk upright and bear more weight on our knees.

22.4 Evolution of Hominids

An evolutionary tree traces the evolution of a group of organisms over the course of time to the original common ancestor. Included in this interpretation of evolutionary events are the approximated times of divergence from others in the group. When two groups diverge from a common ancestor the genes and proteins are nearly identical. These will develop separately and continue to digress from each other over time. Paleontologists use anatomical features when determining if a fossil is hominid. The primary hallmark is bipedal posture.
The hominid is believed to have started with the australopithecines, discovered in Africa in the 1920s. She is dated about 2.8 MYA (million years ago). Anatomy suggests that this hominid walked upright and had a relatively large brain (500cc).
Below is a chart of various discoveries and the interpretations of such:

Some debates over the lineage of some fossils indicate that it is not always clear if the find is hominid or ape. One fossil, called Sahelanthropus tchadensis, dated 7 MYA, is a skull with hominid-like teeth but an apelike braincase. Orrorin tugenensis is another fossil, dated 6 MYA, with canine teeth, but has bipedal posture.

22.5 Evolution of Humans

Fossils with a brain size of 600cc or larger, human-like jaw and teeth configurations, and have evidence of tool use are labeled with the genus homo.
Homo habilis is thought to be the first ancestor to modern humans. The brain size is as large as 775cc (45% larger than the australopithecines) and the teeth indicate they may have been omnivores. Campsites with bones nearby have cut marks which indicate the use of tools. Their skulls suggest that they may have had the ability to communicate with speech also indicating that they may have hunted in groups.
Homo erectus is dated between 1.9 and .3 MYA. It is thought that dissimilarities in some discoveries suggests that different species have been included in this group. Homo ergaster is one such group and is thought to have migrated from Africa to Asia 1.6 - 1.9 MYA. By now, the homo erectus brain capacity is approximately 1000cc. It has a flatter face with a projected nose and is the first hominid to use fire. They wielded axes and cleavers.
Homo sapiens are believed to have evolved from homo erectus. Multiregional continuity hypothesis suggests that this evolution occurred simultaneously in several different geographical areas. Out-of-Africa hypothesis argues that the same result could not have occurred is all those different places. It suggests the H. sapiens evolved only in Africa and migrated to Europe and Asia only 100,000 years ago. This spawned a debate and most recently a study of DNA supports the out-of-Africa hypothesis.
Neandertals are dated around 200,000 years BP (before present). Their brains were larger than the homo sapiens, but the homo sapiens replaced them. They were more muscular and it is thought they needed the larger brain to control the additional muscles. They lived in caves or houses, used fire, and had a variety of tools. They also buried their dead and may have had a religion indicating they could think symbolically.

Before and after . . .,0.jpg

Cro-Magnons lived 45,000 to 10,000 years ago and may have caused the neandertals extinction. They may have lived together in Europe 40,000 years ago, but did not interbreed as evidenced by the differences in DNA. If this is true, then the Neandertals are cousins and not ancestors. The Cro-Magnons were the first to throw spears and make blades. The may be responsible for the extinction of mammals like the giant sloth, mammoth, sabor-toothed tiger and ox.
Human variation is another topic for biologists. It is suggested that adaptations occurred to accommodate the environment in which the people were living. Darker skin is more protective against UV rays. White skin produces more vitamin D. Short, bulky people adapt better to cold climates. A tribe in E. Africa have long limbs and a light build which is helpful for cooling. Perhaps other differences without a known adaptive reason, are merely due to genetic drift.

The cycle of life . . .
One more. . .

Chapter 23: Global Ecology and Human Interferences

23.1 The Nature of Ecosystems

Where ever organisms are found, they live in a biosphere. The biosphere, Earth, is an ecosystem wherein organisms react with other organisms and matter. Homeostasis is maintained between all creatures and substances, somewhat like the homeostasis within our bodies.
A biome is defined by temperature and rainfall amounts in areas of similar communities of plants, animals, and soil organisms also referred to as ecosystems. There is the rain forest and the desert, tropical grasslands (savannas) and temperate grasslands (prairies), The taiga – cold northern coniferous forest, and the tundra at the North Pole which has a short growing season and long winters. These are just a few.
Aquatic ecosystems are divided into the types of water (salt or fresh). Oceans, reefs and marshes comprise the salt water category. Lakes, rivers and ponds comprise the fresh.
Abiotic components are without life. Biotic components are living things and they are categorized according to what they eat. Autotrophs eat abiotic substances and use an outside energy source to create organic matter. Plants and algae are the major photosynthesizers on land.
Heterotrophs eat biotic components. They are herbivores – plant diet, carnivores – animal diet, and omnivores – plant and animal diet. Detritus feeders are decomposers that feed on dead organic matter. Every part has a niche or role in the ecosystem.

23.2 Energy Flow

Energy flow and chemical cycling is the process whereby producers derive energy from the sun and take in inorganic nutrients and begin chemical cycling. After photosynthesis, they produce organic matter for themselves and the consumers. The energy flow is passed as nutrients which are converted to heat and dissipates back into the biosphere. Even undigested nutrients eliminated as waste is digested by the detritus feeders and returned to the cycle as water and carbon dioxide.

Below is a picture depicting the energy flow of a trophic food web:
Trophic (feeding) relationships are demonstrated by the levels in which they are placed. The size of the organic matter does not necessarily correlate with the size of it’s contribution. Dead, organic matter from the detrital food web is a rich source of energy.
Only 10% of energy is passed on from one level to the next. That explains why there are fewer carnivores in each food web.

Picture depicting ecological pyramid:

23.3 Global Biogeochemical Cycles

The Water Cycle – the sun heats up bodies of water causing evaporation. The evaporated water rises to form clouds and rains down on earth. Water runs off the terrain back into the bodies of water and some of the water is absorbed into the ground to become an aquifer. Humans interfere with the water cycle by 1) using water from the aquifers 2) cover terrain with buildings and roads eliminating absorption of rain into the soil and 3) add pollutants to water.

The water cycle:
The Carbon Cycle – the CO2 in the atmosphere is where carbon is exchanged. Plants take up carbon dioxide from the air and incorporate is into nutrients for the other webs. It is then returned to air as carbon dioxide and the cycle repeats itself. In aquatic systems, CO2 combines with water to form a bicarbonate ion. Algae uses this and produces food for themselves and other webs. In turn, respiration gives off carbon dioxide which becomes the bicarbonate ion and the cycle repeats itself. Organic carbon is present in the living and dead organisms in the reservoirs of the world. Decomposition contributes CO2 to the atmosphere as well.
The destruction of forests and burning of fossil fuels is disturbing the equilibrium in transfer rates of CO2. The gasses humans are producing (CO2 andothers) are thought to be producing a “greenhouse effect” which in turn is warming the planet unnaturally. Predictions of a major disruption in temperature and flooding and droughts.
The Carbon Cycle:
The Nitrogen Cycle – makes up 78% of the atmosphere. It is not used by plants and is perceived as a limiter of plant growth. Nitrogen is converted to ammonium and is then utilized by plants. Some bacteria are able to affix nitrogen to hydrogen to form ammonium thereby making it available to plants to form proteins and nucleic acids. Nitrogen combined with oxygen forms nitrates and is also utilized by plants. This reaction occurs when atmospheric phenomenons produce enough energy. Cosmic radiation, meteor trails and lightning are examples of these. This is called nitrification.
Bacteria is once again responsible for converting nitrate back to nitrogen gas and back into the atmosphere. Humans alter the transfer rates of nitrogen by producing fertilizers. The runoff causes overgrowth of algae in lakes which, in turn, burns up too much oxygen and kills fish. Fossil fuels also contribute nitrogen oxides and sulfur dioxides which combine with water vapor to produce “acid rain”. This corrodes marble, metal and stonework and kills natural vegetation.
The Phosphorus Cycle – used by plants and will become part of a variety of molecules including phospholipids, DNA and RNA, and ATP. Phosphorus is trapped in oceanic sediments and will deposit on land after an upheaval. Weathering of rocks deposits it into the soil and becomes available to plants. Animals eat the plants and the phosphorus becomes incorporated into bones, teeth, and shells. Decay causes the phosphate ions to become available to producers again. Phosphorus is not found in the air, so this is a sedimentary cycle. Human beings mine phosphate for use in fertilizer and detergents. This results in cultural eutrophication (overenrichment) of waterways. Biological magnification is the overconsumption or absorption of substances resulting accumulation of higher levels not normally attained. PCP and DDT have been found in breast milk, we are the final consumers. Our seas have been exploited for 50 years resulting in alarming decline of some species of marine life.
The Phosphorus Cycle

Chapter 24: Human Population, Planetary Resources, and Conservation

24.1 Human Population Growth

The human population is experiencing exponential growth. This began after 1750 and began to steeply increase in less-developed countries (LDC’s) around 1950. It is expected that the world population will increase 78 million annually. The growth rate of a population is determined by the difference between deaths and births per 1,000 people per year. It is currently at 1.2% globally. The carrying capacity is the maximum amount of population that the environment can support. We don’t know what the Earth’s capacity is for the human population.
Population growth by region:

More developed countries (MDC’s) have a lower growth rate than the LDC’s. MDC’s have a better quality of living. Much of the LDC populations live in poverty. As a whole the MDC’s growth rate is 0.1%, the US is 0.6%. The LDC’s growth rate is 1.6%, but some countries still average higher rates where women are having more than 5 children each. The LDC’s population may increase from 5 billion to 8 billion by 2050. Asia has 56% of the world’s population and only 31% farmable land. Of the 15 most polluted cities in the world, 12 are in Asia. Because of the large percentage of women entering their reproductive years in LDC’s, they are most certainly going to grow in population even if they produced only 2 children per household.

24.2 Human Use of Resources and Pollution

Resources are described as nonrenewable (land, fossil fuels, and minerals), or renewable (water, solar or wind energy, plants, and animals). As humans utilize resources, pollution occurs. The greater the population, the more pollution is produced.
Land is a limited resource. Forty percent of the population live by the coast. Many of the naturally occurring habitats for wildlife are destroyed from this choice. We have filled in wetlands to use for our own habitation to the detriment of many types of animals.
Overgrazing and foraging causes desertification of semiarid lands. Deforestation is the removal of trees for settling or building materials. This can also lead to desertification.
Example of deforestation
Water is considered to be renewable, but is scarce in some areas. Where water is available, is should be drinkable, but is impure in some areas. Seventy percent of all clean freshwater is used to irrigate crops. in the MDC’s, more water is used for flushing toilets, bathing, and lawns, than for drinking.
Dams provide water and electricity, but prevent rivers from running as they used to. Drawbacks are seepage and evaporation, increased salinity downstream, and the filling of the reservoir with sediment. People have been removing water from the aquifers (underground stores of water). The High Plains Aquifer stretches from South Dakota to Texas, and has been reduced by more than half because of groundwater pumping. This causes subsidence, settling of the soil, which may produce sink holes. Saltwater may back into streams and aquifers reducing the supply of freshwater. There are technologies available to reduce the demand of freshwater, but they are seldom used.
The food supply has expanded to accommodate the growing population, but some harmful methods have been implemented. Some farmers only plant one crop. This makes it more vulnerable to devastation by one parasite. Fertilizers, pesticides and herbicides have polluted groundwater and beneficial soil organisms. Irrigation methods have reduced the aquifers. Farmers also use a lot of fossil fuels to accomplish their tasks.
Soil loss and degradation are problems facing farmers. Simply, the rows utilized to accommodate tractors has caused the US and Canada to have the highest rates of soil erosion in the world. The accumulation of minerals in the soil from irrigation practices, has rendered the land unsuitable for growing crops. Scientists developed wheat and rice varieties for the LDC’s, which are causing the same issues over there. Genetic engineering is another approach to developing hardy and resistant crops. The consequences of these are not fully understood. Domestic livestock is a huge consumer of resources and produces a lot of pollution as well.
Energy is renewable and nonrenewable. Nuclear power provides 6% of the world’s energy supply. Disposal of waste is an issue, because it is radioactive. Fossil fuels provide 75% of the energy supply. The US is only 5% of the world’s population, but uses half of this resource. This is best explained by this statement: one person in the US uses as much energy in one day as a person in an LDC uses in a year. The burning of fossil fuels releases carbon dioxide into the atmosphere which is theorized to contribute to a global warming trend. This continues to be a debatable point, even in scientific circles. Renewable resources are growing in availability. Hydropower is produced from dams and is not without problems as mentioned earlier.
Unknown Dam

Smaller dams with less output and less environmental impact may be the answer. Geothermal energy is emitted from underground naturally-occurring radiatioin that heats rocks which are in contact with water. Steam and hot water are produced and can be used to run steam-driven turbogenerators.
The most active geothermal resources are usually found along major plate boundaries where earthquakes and volcanoes are concentrated. Most of the geothermal activity in the world occurs in an area called the Ring of Fire. This area rims the Pacific Ocean.
Wind and solar power are viable energy producing options. Hydrogen fuel cells are very promising developments and give off water as a byproduct.

Solar plant:

The mining of minerals causes damage to the area of mining and heavy metals are dangerous to our health. These wastes build up in our environment as well. Some of these disrupt our endocrine systems. Could this be why so many people have Thyroid disorders? Chloroflourocarbons were instrumental in the thinning of our ozone and since their ban, the ozone is predicted to recover by 2050. Because pollution is absorbed along the food-chain, contaminants have been found in human breast milk.

24.3 Biodiversity

Biodiversity refers to the variety of species in a given area. Loss of habitat can cause a species to become extinct. It’s possible that all coral reefs will disappear in the next 40 years. Species unnaturally introduced into an area can become invasive and crowd the natural wildlife out of their existence. Pollution produces acid deposition, global warming, ozone depletion, and the deposition of synthetic organic chemicals. Overexploitation for obvious reasons, reduces resources and/or wildlife and can leave an area decimated and unlivable.

Biodiversity is valued for various reasons. Three main reasons for maintaining biodiversity are
Medicinal Value: Biota are the sources of most prescription drugs. It is surprising where these miracle cures are found. Flowers in Madagascar have increased the survival rate of leukemia from 10% to 90% in children. Similar tales are abundant. In agriculture, natural predators are being used to combat viruses and pests. Maintaining populations of species for consumption is also to our benefit.
Rosy Periwinkle, surprising lifesaver

Partially treating sewage and allowing decomposers to finish the job benefits our environment. Also, biological communities can also remove heavy metals and pesticides and save $50,000 per 2.47 acres. Forests and other ecosystems slowly release water back into rivers reducing the occurrence of flooding. These also prevent soil erosion. Biogeochemical cycles that occur naturally keep vital elements and energy in balance.

24.4 Working Toward and Sustainable Society

The population growth of the LDC’s and the consumption of the MDC’s both need adjustments if we are to achieve a sustainable society. New innovations and foresight must be embraced and each person must make lifestyle changes to support these choices. If we learn from the natural systems in place, we will use renewable resources. In urban areas, we should preserve our topsoils, the richest in nutrients. Composting, multi-use farming, natural pest control, planting of multi-purpose trees, maintaining and restoring our wetlands, using renewable energy and buying locally will all impact our environment positively. In the city, we need to incorporate green belts and use roof tops for gardening as well. Using solar or geothermal energy and utilizing old, run-down areas in the city before building outward would also benefit the environment.
Chicago Rooftop

We need to assess what it is we value in order to prioritize our commitments and move forward.

Sunday, April 20, 2008


1. Day 2 – Fertilization. This is significant because without this, there would be no baby.


2. 4th week - heart is beating. For many centuries, the beating heart was used to establish whether or not someone was alive. To this day, we still assess that for one of the signs of life.

3. 1 ½ months – brain waves can be measured with EEG. Heart chambers and valves are formed. I thought this was significant because it meant heart and mind are beginning to function. Sort of analogous to the makeup of all that is human, thinking and feeling beings. I did not know I was investigating an area of debate between various groups on the topic of abortion and the fundamental question of when does life begin. Seems to me this little person is alive. We were all there once.

3 month old fetus:

4. Week 9 - Basic brain structure of the fetus is complete. Again, the ability to think and reason is one of the things that sets us apart from other species. I realize this says “basic brain structure”, but it also means the potential is there.

5. 3 months - capable of hearing. I think that some sounds can be heard through the womb and this is important to recognise. Maybe some sounds will agitate the baby.

Now we can share music. Time to put on the headphones.

Also sex organs can be detected. This is significant because we can pick a name and paint the walls of the nursery, if the sonographer is competent and the baby is cooperative.

6. 4 months: babies sucking thumbs. This is important because the fetus can self-comfort. I wonder if this is an accident that the thumb touched the mouth and the instinct to suckle drew the thumb in or it becomes a conscious action.

7. 5 months: baby can kick hard enough for mom to feel. The pic below is actually a five month fetus sucking his thumb. An amazing photo. I think that feeling the baby moving inside your own womb is an amazing experience and significant because you become aware of this lively, purposeful baby. Each one of my kids had different types of movements which was consistent with their personalities.

5 month old fetus:

8. 7 months – taste buds have developed. I personally like that my taste buds work and think this is a very important and vital function.

Yummmm . . .

9. 8 months – most organs are fully developed except for the lungs. This means that the baby is almost ready. The last month will be the longest.

Eight month fetus:
10. 9 months – now fully developed and can survive outside of mom’s body. The baby will drop down and if normally positioned, the head will rest on the cervix, ready for delivery. The most anticipated event in the world! All systems are go and hopefully all will go well.

The fruit of our labor:

Saturday, April 19, 2008

Unit IV Compendium

Compendium Unit IV
Chapters 16-17
16.1 Human Life Cycle

Human reproduction is possible when a person completes puberty. In girls, that is reached at age 11-13 and boys at 14-16 years of age. To follow are the different functions of organs for each sex:
Male: Produce sperm Female: Produce eggs
Nurture sperm Transport egg to uterus
Penis delivers sperm into vagina Vagina receives sperm and provides conduit to egg
Testes produce sex hormones Uterus provides locale for fetal development
Vagina is pathway for delivery
Ovaries produce sex hormones
There are two types of cell division: mitosis and meiosis. Mitosis is duplication from one cell dividing producing two cells each containing all 46 chromosomes. Meiosis occurs only in the testes and ovaries of the reproductive organs. Each sperm and egg cell produces contain only 23 chromosomes so that when united, the zygote will have all 46 chromosomes.

16.2 Male Reproductive System

The testes (gonads) are the primary sex organs of the male reproductive system. The testes produce sperm and sex hormones. The scrotum will regulate the temperature of the testes by raising or lowering the testes from the body. Too warm and the sperm will not be viable. The sperm than mature and are stored in the epididymides. The sperm then leave the epididymides and can be stored in the vas deferens or transported onward. After entering the ejaculatoroy duct, nutrients and semen are contributed by the seminal vesicles, prostate gland, and bulbourethral glands.
Male reproductive anatomy:

I will not be commenting on the act of intercourse, since this is a public internet site. There may be greater than 400 million sperm in 3.5 mL of semen.
The Seminiferous Tubules are the locations of sperm production. It takes 74 days for sperm to develop. Mature sperm have 3 parts, head, middle piece, and tail. The head is covered by acrosome, which contains an enzyme to penetrate the egg. The middle piece has mitochondria which provides energy for movement. The tail flagellates to propel the sperm. The interstitial cells in the testes produce the sex hormones. The hypothalamus in the brain produces gonadotropin-releasing hormone (GnRH) that stimulates the anterior pituitary to release gonadotropic hormones, both follicle stimulating (stimulates sperm production) and luteinizing hormones (stimulates testosterone production). Testosterone maintains normal development and functioning of the sexual organs. It also gives males some of their male traits, such as greater muscle mass, lower voices, adam’s apple, broader shoulders and greater height.

16.3 Female Reproductive System

Ovaries are the female gonads. The produce eggs, estrogen and progesterone. The ovaries are located at one end of the fallopian tubes. They are not connected. The fallopian tubes have fimbriae (projections that sweep over the ovaries) and cilia which “brush” the eggs after they emerge from the ovaries in the direction of the uterus.

An egg is only viable for 6-24 hours until fertilization occurs. Fertilization usually occurs in the fallopian tube. The developing fetus (zygote, at this stage) arrives and implantation occurs in the thickened uterine lining. The uterus prior to emplantation is approx. 5 cm wide and can stretch to over 30cm wide when pregnant. The lining of the uterus is called the endometrium comprised of two layers, the basal laer and the functional layer. The cervix is at the base of the uterus and leads to the vaginal canal.

The external genitalia is collectively called vulva. The outermost folds are called labia majora. Moving medially, the next folds are called labia minora. Ventrally, they join to form a foreskin for the clitoris, this is the organ of arousal in a woman. Just dorsal to that is the urethra and then the vagina.

16.4 Female Hormone Levels

Hormones cycle an average of every 28 days. This is ovary-driven. An ovary initially contains as many as 2 million follicles and only about 400 will ever mature to produce an egg. Generally speaking, only one egg is produced every month.
Genetic spicing gone wrong. The chicken must have died,
there's not a full dozen.

Back to the basics . . .
The human cycle is depicted in the picture below:

After the oocyte is released, the follicle develops into a corpus luteum. This produces progesterone and a little estrogen. As in men, the hypothalamus controls sexual function by releasing gonadotropin-releasing hormone. This stimulate the pituitary to produce FSHand LH, which control the ovarian cycle. During the first half of the cycle, the FSH stimulates the follicle in the ovary to produce estrogen which cignals the hypothalamus to secrete GnRH which in turn leads to a surge of LH production by the anterior pituitary and ovulation. The LH matures the corpus luteum and progesterone is secreted. Estrogen is responsible for our feminine traits. In encourages fatty accumulation under the skin, lending a softer appearance. The ovarian cycle will cease at around 50 years of age. The ovaries fail to respond to GhRH and no longer secrete estrogen and progesterone.
The uterine cycle is the response to the fluctuating hormones. The lining of the uterus will thicken to accommodate a possible developing embryo and this will slough off if an egg is not fertilized that month resulting in a menstrual period.
Pregnancy: Once a sperm has fertilized an egg, it becomes a zygote. This implants in the lining of the uterus. At the place where the molecules of fetal blood and maternal blood are exchanged, a placenta will develop. Progesterone production increases and will stop follicles from producing more eggs during the pregnancy. The placenta will begin to produce progesterone and estrogen and the corpus luteum will regress.

16.5 Control of Reproduction

There are multiple methods available to prevent pregnancy from occurring. They are listed below and these rates are applicable only when the methods are used correctly:

Abstinence is the only guaranteed method of birth control and it also has the advantage of no STD transmission. Morning after pills are administered 1-7 days after intercourse has occurred. It upsets the progesterone cycle preventing the implantation of the embryo. RU-486 is a different type of morning-after pill that causes the endometrium to slough, of course the embryo goes with it.
Infertility is deemed such after one year of regularly attempted impregnation. Low sperm count is one cause of infertility. Too much sitting, smoking or drinking alcohol can cause this. Overweight women may fail to ovulate. Blocked oviducts from pelvic inflammatory disease and endometriosis can prevent the journey of the egg to the uterus also causing infertility.
There are technologies available to help infertile couples have children. Artificial insemination is when the sperm is placed in the vagina by a physician. This is helpful when the male has a low sperm count. Sometimes fertility drugs are given to the woman to produce one or more eggs and the sperm is placed directly into the uterus. In Vitro Fertilization, conception is attained in the lab. Then the embryos are transplanted in the uterus of the woman. Sometimes, other women are contracted to give birth. The egg and sperm can be from the desiring parents. Scientists can also inject a single sperm into and egg and then transplant it into the mom’s uterus.

16.6 Sexually Transmitted Diseases

Viral Sexually Transmitted Diseases
HIV – precursor to AIDS. First stage of infection can be asymptomatic, but highly contagious. This may develop into AIDS when the helper T cell count falls dangerously low and the host cannot fight infections. AIDS patients usually die from opportunistic infections that would normally be stopped by a healthy immune system.
Genital Warts – caused by the human papillomaviruses. The carriers may not have warts and may have less noticeable flat lesions. A baby can pick up this virus as it passes through the birth canal. Vaccinations are available for some the common strains of this virus. 90% of all cancers of the cervix are thought to be caused by this virus.
Genital Herpes – Herpes simplex type 2. This is presented with blisters, tingling or itching sensations. Some events may be accompanied with fever, pain with urination, or swollen lymph nodes and the person is very contagious at this time. Newborns may pick this up through the birth canal.
Several types of hepatitis are acquired through sexual transmission. This generally causes liver damage.

Bacterial Sexually Transmitted Diseases

These are curable with antibiotics. Some resistant strains may require taking stronger drugs for a longer amount of time.
Chlamydia – mild or asymptomatic in women. If undiagnosed, can spread from the cervix to the fallopian tubes causing pelvic inflammatory disease, a very painful condition which may result in infertility.
Gonorrhea – can lead to pelvic inflammatory disease in both males and females. Gonorrhea will infect whatever part was exposed to the virus and can be spread to internal parts, causing heart damage or arthritis. Because of increased resistance to antibiotic therapy, 40% of all strains don’t respond to therapy.
Syphilis – also potentially deadly, begins as a small ulcer (chancre) that resolves on its own. Then the infected person will develop a rash that does no itch and is seen on palms and soles of feet. This, too, will resolve. The last stage may affect the cardiovascular system by causing aneurysms and ulcers on the skin or internal organs. Early diagnosis and treatment is vital for successful treatment.
Other Common Infections
Bacterial vaginosis is asymptomatic and can be due to nonsexual reasons, or may have been passed on from infected males. Candida albicans (non-sexual) and Trichomonas (sexual) are vaginal infections treated with oral or topical medications.

Chapter 17: Development and Aging

17.1 Fertilization

The flagellum moves the sperm toward the egg. The arcosome on the head contains enzymes that will penetrate the zona pellucid.

As soon as the head touches the plasma membrane, it will depolarize prohibiting the penetration of more sperm. When a sperm enters an egg to form a zygote, fertilization occurs.

17.2 Pre-Embryonic and Embryonic Development

Immediately after fertilization, the cells begin to divide within the zygote but it doesn’t increase in size. Then the daughter cells begin to increase in size. At morphogenesis, the cells migrate and begin to form the shape of the embryo. Differentiation is when the cells begin to function according to their structure. The nervous system is the first to appear.

The structures that support the embryo are pictured below.
Chorion – becomes the fetus’ half of the placenta.
Allantois – extends away from the embryo, collects urine before bladder develops. The blood vessels will become the umbilical blood vessels.
Yolk Sac – first embryonic membrane to appear. It contains a small amount of yolk. The placenta will soon take over.
Amnion – contains fluid which will protect the baby.

From a zygot, to a morula, to a blastocyst, this will separate into the embryo inside and the outer layer called a chorion. Embryonic development begins the second week. The chorion will secret enzymes to eat away some the tissue of the endometrium and implant. It will also secrete human chorionic gonadotropin which will preserve the lining of the uterus until the pregnancy is completed. This is the start of gastrulation, forming of three primary germ layers:
Ectoderm: outer layer forming the epidermis, lining of oral cavity and nervous system
Mesoderm: middle layer forming the skeleton, muscles, dermis, CV system, urinary system,
reproductive system, outer layers of respiratory and digestive systems
Endoderm: inner layer forming the digestive tract and respiratory tract and their glands.
In the third week the nervous system and the heart begins to form. At the end of the fifth week the umbilical cord will be fully formed. Little limb buds become apparent. At the end of eight weeks, the nervous system has developed enough to permit a startled response. The embryo is about 1.5 inches long and all organ systems are present.

In the picture, ten models, approximately life-sized, represent eight weeks of embryonic development, at the end of which main organ systems, limbs and features have taken shape.

17.3 Fetal Development

At the third month the uterus is the size of a grapefruit and gender can be detected by ultrasound.
By four months, the skeleton is visible and hair is growing. At five months, a coating is developing on the baby and the heartbeat can be heard. By the seventh month, the testes descend in to the scrotom and the eyes are open. At eight months, the baby begins to develop that cute fat and is ready for birth at nine months.

Cute baby fat . . .

During pregnancy, the placenta will become the source of progesterone and estrogen to discourage follicle stimulation and to maintain the endometrium.

The path of fetal circulation

Blood is received from the placenta, goes through the liver and is received in the right atrium. Some of it is shunted through the foramen ovale directly to the left atrium, then the left ventricle. Some of the blood in the right atrium will be pumped into the right ventricle where it will be sent through the pulmonary trunk and arterial duct to the aorta as well. The ventricle pumps the blood to the aorta and is then sent to the head and body and returns to the right atrium. Desaturated blood is returned to the placenta via the umbilical arteries. At birth the foramen ovale and arterial ducts will usually close in order to route the blood through the lungs when they start working.
At six weeks, the genitals are indifferent – no specific gender. A gene (SRY) will signal for testes to develop and the testes will produce testosterone. Without SRY, ovaries will develop. Genitals will develop into distinct gender at around 14 weeks.
People with the XY chromosome are males and XX are females. There are a few abnormal developments that make the determination ambiguous. The androgen insensitivity syndrome is when the membrane receptors for testosterone are ineffective. The person will develop as a female and it is not discovered until she fails to menstruate.

17.4 Pregnancy and Birth
Needs no introduction . . .

Initially, one the the first symptoms of becoming pregnant is nausea, vomiting or loss of appetite. She may also become tired. This usually subsides after the first trimester. Energy and stamina are reported often throughout normal, progressing pregnancies. She will gain weight from the enlarging uterus and baby developing inside, her breasts are also enlarging, and her own increase in body fluid (40% increase in blood volume) and fat stores. Increased Progesterone levels will relax smooth muscles also causing perhaps, heartburn and constipation. The tidal volume of her lungs will increase 40% and carbon dioxide levels will fall 20%. Pressure from the uterus on the bladder can cause frequency and incontinence. Pressure on the vena cava will decrease venous return and may cause varicose veins and swollen legs.
As she approaches labor, contractions experienced throughout the pregnancy will become stronger. False labor or Braxton Hicks contractions may fool her into believing it is time for delivery. True labor is defined by contractions every 15-20 minutes lasting at least 40 seconds or longer.
The stretching cervix stimulates the release of oxytocin from the pituitary gland. This stimulates the uterine muscles. During Stage 1 of labor the uterus will push the baby harder against the cervix. When the cervix is completely dilated, Stage 1 is over. Stage 2 is the birth of the baby. Contractions occur more frequently to push the baby through the birth canal. During a normal presentation, the head appears first. Complications may occur if a different part presents. Stage 3 is the delivery of the placenta. The uterus continues to contract which shrinks the uterus and displaces the placenta.

Definitely worth the effort . . .

17.5 Development after Birth

Gerontology is the study of aging. It has been the pursuit of many to find the fountain of youth. Research as to why we age has produced a mitochondrial hypothesis – when mitochondria produce energy, they produce free radicals (extra electrons). These attach to other molecules which become disabled and are destroyed. A restricted food intake shuts down the genes the turn on the activity of the mitochondria.
Many hormones also diminish or receptors become resistant. The thymus gland decreases in size and our immune response diminishes. Cancers increase in incidence as we age. Collagen stiffens and effect the elasticity of tendons and ligaments and skin (becomes thinner and less elastic). Hair follicles lessen in number and a decrease in melanocytes causes what hair is left to turn gray and skin to pale. Cardiovascular problems are associated with loss of muscle and hardening and narrowing of the arteries. Blood flow is reduced to all systems of the body and everything functions subpar. Medication must be closely monitored because the filtering of the kidneys and liver are diminished and unsafe levels can occur when elimination is compromised. The digestive tract also slows causing hearburn and slow elimination. Good news is that few neural cells of the cerebral cortex are lost during the aging process. It takes longer for a senior to learn new facts, but one can if given the time to do so. Diminished hearing and vision, glaucoma, loss of muscle mass, inability to hold urine, bone density decline, arthritis and weight gain are all problems shared by the elderly. Why are these the “Golden Years?”
Women enter menopause around 50 years of age and men enter andropause somewhat later between 50-90. Both signify a decrease of the sex hormone and diminished libido.
Many of the problems associated with aging can be avoided with good health habits developed earlier in life.