EVOLUTION and NATURAL SELECTION (30 pts)
a. What is a mutation? Provide 3 examples of different mutations causing specific diseases in human population. For each example explain what kind of mutation that is (ie. A point substitution, a chromosomal duplication etc).
Mutation is a genetic mistake(s) that occur during DNA replication. 1. Progeria accelerated aging; mutation in the LMNA gene
2. Hypertrichosis excessive hair on the shoulders, face and ears; implicate it to a rearrangement of chromosome 8. 3. Severe Combined Immunodeficiency Disorder born without an effective immune system.
b. Why is genetic drift more significant for small populations?
The small population numbers would have resulted in specific genetic traits being passed down to the subsequent generations. The lack of any other gene pools to intermix with would have allowed for specific traits to pass down within a community.
c. In week 2 we discussed that individuals can have no more than two different alleles for each trait. In population genetics we can operate with multiple alleles for each trait. How is it possible?
Due to the increase of humans moving and evolving areas, polygenic trait is the effect caused by the interaction of different genes. Blood pressure is not the result of a single gene. The phenotype is a mixture of a person’s weight, metabolism, etc. Each of these factors have multiple alleles.
d. Hardy-Weinberg equilibrium is an important approach for predicting the dynamic s in allelic distribution. It uses 4 assumptions. List those assumptions and explain for each of them, why they are unattainable in real life. You can organize your answer as a table.
1. Random mating, most humans tend to mate with other individuals who share common similarities as themselves. 2. Mutation, add variation within a population, effects are limited. 3. Genetic drift, population size has to be limited
4. Imbreeding, it’s gross and not common.
e. Does artificial selection increase overall fitness? Why or why not?
Yes. Through sexual selection, if the female continues to choose physical fit, strong males, and it continues down for generations the members will continue to reproduce strong members. I read once, before the civil war, strong male slaves were force to mate with strong female slaves to reproduce strong members. Kind of what happens now for example with pitbulls.
f. Discuss effects of genetic bottlenecks. Provide one real example.
Is a reduction of a population size due to natural disasters or human activities. A tsunami, earthquake
g. Name and briefly define all types of speciation.
1. Allopatric, a population split in two isolated populations. 2. Peripatric, new species formed in isolated populations. 3. Parapatric, partial separation acting as a source of natural selection. 4. Sympatric, single ancestral species in original geographic location. INTERACTION BETWEEN SPECIES (15 pts)
a. What is symbiosis? Provide 3 examples
Symbiosis is a relationship between two or more different organisms of different species. 1. Mutualism: this is when both species involved benefit from the relationship. 2. Parasitism: this is when only one species benefits, and the other is actually harmed. 3. Commensalism: this is when only one species benefits, but the other isn't harmed by the relationship either.
b. Compare and contrast predation and parasitism. While intestinal parasites are clear parasites, leaches are predators, same as mosquitoes as opposed to clearly parasitic lice. Venture a logical explanation based on your comparison. A parasite is an organism that consumes its host for either food or shelter. While a predator kills its prey. They are similar because both depends on another organism or prey for food. c. What is innate behavior? Provide 2 examples.
A fixed action pattern.
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