Nats 109 Exam 3 Review(1)

Topics: Sexual dimorphism, Sexual selection, Organism Pages: 12 (3268 words) Published: May 16, 2013
1.Explain the three hypotheses for the recent changes in the toxicity of venom in different species of rattlesnakes found in the United States.
- Interbreeding between snakes with different venom profiles.
- Geographic distribution (genes shifted eastward)
- Convolution
- Old rattlesnakes have high concentration of toxic.
2.What is an “evolutionary arms race”? Describe how this applies to one of the hypotheses suggested to explain toxicity of venom in rattlers – i.e. Using the 3 specific requirements for natural selection, discuss how rattlesnake venom toxicity could increase due to an arms race.

Variation, inheritance, deferent reproduction. In variation, high level of toxic will survive and produce more offspring so next generation will have more concentration of toxic.
2.Why is cancer a multicellular organism’s disease?
Uncontrolled cell because they produce thousands of single cells and they produce new organisms. They divided constantly (have chance to produce new)
3.Explain the following sentence: “What cancer has on it side is mainly the astronomical number of chances it gets to achieve success against the immense odds.” Your answer should include an explanation of why cancer gets an “astronomical number of chances” and why there are such “immense odds.”

Portions: they attack cells and then kill them.
Anti cancer mechanisms, so cancer has to go through all of them.
4.What types of anti-cancer mechanisms exist in our bodies?
5.Is cancer a result of genetics? The environment? Viruses? Parasites?
All of them
6.What is the p16 protein? What is the benefit of having the p16 protein? What is the drawback of the having this protein?
Anticancer, it will attack any sells that replicate itself, but it makes us old (natural selection)
7.Why is Retinoblastoma so rare? Explain why it is unlikely that natural selection has selected against Retinoblastoma.
Because we get it when we are before 5 years old. Retin cells stop dividing when we are 5 years old. Natural selection can not act with these cells because they are rare.
8.How has the FAS gene been important to human evolution? How does this gene affect cancer cells?
FAS genes acids are important for brain development. Also, cancer use them to produce energy and to grow.
9.What is the “tug-of-war” that exists between pregnant mothers and their fetuses? How has this tug-of-war benefitted cancer cells?
Umbilical cord
Cancer takes these genes and use them. (From blood)
10.Explain why a defense against cancer does not have to eradicate the disease completely to be favored by natural selection. Has natural selection already selected against cancer? How do you know if it has or has not?

Natural selection selects against cancer through age, so at late age the bodies might get cancer. (most cancers are in late ages). In addition, it does not replicate, and it has to postpone.
Most people get it in production age.
11.Explain how are some reproductive cancers in women related to the number of menstrual cycles they have had during their lifetime.
Because they need tons of energy. (prenatal control)

1.What is an adaptation?
A trait that allows an organism to live successfully in its environment. Also, it is a characteristic of an organism that has been favored by natural selection. Adaptations are traits that have been selected by natural selection.

2.What is camouflage?
Animal look like things in environment (rock, twig, leaf)
3.What is mimicry?
Animal uses colors and markings to look like another animal.
4. Unlike many animals, Xenophora gastropods are not naturally camouflaged (i.e. their genetics do not code for a naturally camouflaged body). In what unique way do they camouflage into their environment?

They attach items found on the seafloor as a camouflage
5.In what unique way do Flatfish camouflage in with their...
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