Tuesday, October 11, 2011

Human Variation & Race

1. 1. High levels of radiation disturb homeostasis, or the, “balance, or stability, within a biological system,” by triggering the pigment melanin within a human’s skin (450). Overexposure can lead to mutations of skin cells that can cause cancer. High levels of radiation ultimately cause increases in the production of melanin, except in albinos. Also, these high levels deplete folate, a B vitamin used for developmental processes, which can result in serious fetal neural tube disorders, such as spina bifida.

2. Cultural adaptations to the stress of high levels of radiation include:

a. To cover exposed areas with clothing, sunglasses, or hats

b. use sunblock
c. migration out of areas where UV rays are more intense, such as the tropics.
d. transition from living outdoors to living indoors out of the reach of UV rays.

3. One main benefit to studying this across different clines is to see the patterns of how humans react to these environmental stressors. This is helpful to understand and gain more knowledge of our species. One way this could benefit us is by studying the patterns and correlations between melanin, location, and uv exposure to gain more knowledge about skin cancer.

4. According to the textbook, race refers to the, “geographically patterned variation within a species” (426). Knowing this it is easier and more understandable to study human variation by looking at the environmental influences on adaptations because in different areas of the world, there will be different adaptations to different environments. Essentially, it is easier to study the variation of adaptations through geographically different areas, rather than different races. Although one could use race to understand different adaptations, it is better to use environmental influences to understand this.

Tuesday, September 20, 2011

The Piltdown Hoax

1. 1. The Piltdown Hoax took place in the early 1900s in a village called Piltdown, located in southern England. It began when a man, named Charles Dawson, discovered what appeared to be an ancient human skull, dating back possibly one million years, while digging in gravel. Dawson then invited a geologist and a paleontologist to continue working with him, which led to more discoveries. While digging, Dawson found an ape like jawbone that had human like teeth, which had led many scientists to believe that they had found the missing link that would connect apes to humans. These notions were not questioned by any of Charles Dawson and his accomplice’s fellow scientists due to the fact that the discoverers of the Piltdown man were well respected scientists, until the 1920s when scientists discovered ancient remains in other parts of the world. These remains were quite different than the Piltdown man, in that they were younger, but somehow less human. Then in 1949, scientists used a new technology, which required measuring the fluorine content in bones to determine their age, to determine the age of the Piltdown man bones. They found that they were only one hundred years old, with the jawbone belonging to a female orangutan. The bones had been stained to appear ancient and the teeth had been filed down to appear as if they were human. Although Charles Dawson is assumed to be the main suspect in this hoax, his fellow accomplice’s were also though to have possibly contributed along with the newest assumed suspect, Martin Hinton.

2. 2. Probably the biggest flaw that impacted the scientific process in this discovery was that fellow scientists did not attempt to falsify or test the hypothesis/evidence. It seems that the notoriety of Dawson’s accomplice’s earned him a type of trust, in which his findings no longer needed to be tested. The only viable reason for not attempting to falsify Dawson’s findings was that there was not yet a technology to determine the age of bones.

3. 3. The main aspect that was responsible to revealing the true nature of the bones was the fluoride technology, which was used to determine the age of the bones. Using this, scientists discovered first that the bones could only be around one hundred thousand years old. Later, it was discovered that the bones were actually only one hundred years old, and they had been stained and shaped to appear much older.

4. 4. It is not possible to remove the “human” factor from science, nor would I want to. While occurrences like the Piltdown Hoax are bound to happen when the human factor is present, it allows humans to evolve on a social and mental level rather than a physical one. Also, it is impossible to remove the human factor because humans are the ones making the discoveries. While no one person’s answer is one hundred percent correct, we can aim to perfect our outcomes with the help of our many peers shaping the outcome.

5. 5. I feel like everyone can relate to this story. We all have probably been fooled one time in our lives, whether it was a major or minor situation. A lesson that should be learned from this is to always check your sources, or find information for yourself!

Wednesday, September 14, 2011

Comparative Primate Post

Lemur:


Most lemur’s reside in the tropical rainforests of Madagascar. Madagascar has extreme weather ranging from tropical cyclone floods to extremely dry droughts. This has caused for the Lemur to evolve into a creature that is able to withstand the extreme weather in Madagascar. While some Lemur locomotion can vary from Lemur to Lemur, most are quadrupedal, meaning that they use all four of their limbs to climb or walk. One example of this is the cheirogaleidae, or dwarf lemurs that are quadrupedal and are also climbers. Lemurs can also be vertical clingers and leapers. These specific locomotive patterns may have evolved from using all four limbs to walk long distances or to climb trees, or to swing from tree to tree and to also search for food. Since a lemurs diet mainly consists of fruit, they would need to climb trees to sustain their life.

Spider Monkey:

Spider Monkey’s live in the top layers of the tropical rainforests in Central and South America. They use three different types of locomotion, quadrupedal, suspensory, and bipedalism. Like the Lemur, the Spider Monkey uses quadrupedal while walking, it uses suspensory while climbing, and bipedalism when leaping. Also, like the Lemur, these locomotive traits may have developed as a result of its tropical location among the trees. These three locomotive traits enable the Spider Monkey to survive within the rainforest.

Baboon:

Baboon’s reside in East Africa. Their habitat is easily adaptable and can survive for long periods of time with no water. I had a great deal of trouble trying to find the locomotive patterns of baboons. I did find one source that referred to Baboons as quadrupedal creatures. Baboons live in mostly open areas and often sleep on rocks. This most likely has caused the Baboons to evolve to utilize a trait that could enable them to travel over distances of flat land, in a quadrupedal manner.

Gibbon:

Gibbon’s are a part of the ape family and are found in tropical and sub-tropical rainforests such as China, India and Indonesia. Although their main source of locomotion is through brachiation, or swinging on branches, they also walk bipedally, and occasionally leap. Gibbon’s most likely evolved in tropical rainforests usuing brachiation as their source of travel, and also probably to gather their food, which is essential for survival.

Chimpanzee:

Chimpanzee’s can be found in Africa and Southeast Asia. Unlike the other four explored primates, Chimpanzee’s live in more diverse areas consisting of tropical rainforests, swamps, grasslands, and forests. Chimp’s mostly walk quadrupedally but also walk bipedally. Like the Gibbon, they also travel through brachiation and they are able to climb trees extremely well. These traits developed from the Chimp’s natural habitat. In order for the Chimpanzee’s to survive, they had to develop different forms of locomotion for traveling, resting, shelter, and food.

All of the primates explored in this assignment reside in tropical areas, specifically among the trees (except for the chimpanzee who reside multiple places), except for the Baboon, who takes shelter mostly in open fields. The environment plays a huge role in the development of locomotive traits in these primates. They all require multiple forms of locomotion such as brachiation, quadrupedal, and bipedal. If it were not for their ability to possess these locomotive traits, their survival would be at risk, because it would eliminate some of their ability to travel, and obtain food.

Thursday, September 8, 2011

Analogy/Homology

1. For your homologus traits provide the following information (25 pts):

a. Briefly describe the two different species that possess the homologus trait. (5 pts)

The two different species that possess the same homologus trait are humans and gorillas.

b. Describe the homologus trait of each species, focusing on the differences in structure and function of the trait. Why do these homologus traits exhibit differences between the two species? Make sure your explanation is clear and complete. (10 pts)

The homologus traits are the four limbs (arms and legs), with no tail, that both humans and gorillas have. They are distinct because humans walk on only two of the limbs, the legs, and gorillas walk on all four.

c. Who was (generally, not specifically) the common ancestor of these two species and how do you know that ancestor possessed this homologus trait?

(5 pts)

The common ancestor who possessed this trait were the hominids, or great apes.

d. Provide an image of each species in this comparison. (5 pts)






2. For your analogous traits provide the following information (25 pts):

a. Briefly describe the two different species that possess the analogous trait. (5 pts)

The two different species that possess a homologus trait are birds and bumble bees.

b. Describe the analogous trait of each species, focusing on the similarities in structure and function of the trait. Clearly explain why these analogous traits exhibit similarities between the two species. (10 pts)

The analogous trait that both of these species share are their wings. These species do not really have a similar structure other than that they both possess a heart, eyes and wings. The most clearly defined analogous trait that they both possess are their wings, which they use to fly.

c. All pairs of organisms share some common ancestor if you go back far enough in time. Did the common ancestor of these two species possess this analogous trait? Why or why not? (5 pts)

d. Provide an image of each species in this comparison. (5 pts)


Thursday, September 1, 2011

Thursday, August 25, 2011

8/25 Assignment

1. Although I believe all of these individuals had great influence over Charles Darwin, I believe Jean-Baptiste Lamark had the most significant influence.

2. Jean-Baptiste Lamark is responsible for the, “discredited theory of heredity, the ‘inheritance of acquired traits’”.

3. The point which is affected by Lamark’s work is that, “in order for traits to evolve and change, they MUST be heritable”. This is because Lamark discussed how one inherits their traits which their parents or ancestors acquired over time through adaptation so surroundings.

4. Although Lamark was the first individual who proposed such ideas, Darwin may or may not have developed his theory of natural selection, without it, depending upon if it could have been proposed by someone other than Lamark, or if he came to it on his own.

5. Although Darwin published and presented his book On the Origin of Species, it essentially took him twenty years to do it, because he had been looked down on by the church and even some colleagues.


Works Cited

"Jean-Baptiste Lamarck (1744-1829)." Web. .