The exam will consist of 20 multiple choice questions (worth 1 point each; 5 opt

Question

The exam will consist of 20 multiple choice questions (worth 1 point each; 5 options per question) and one short essay question (worth 5 pts). You will get one of the following essay questions in the exam (the numbers in parenthesis indicate how many points we will award for each part of a question):

1. What is the struggle for existence (1)? Describe one of the conditions required for it to occur (1). Give an example of struggle for existence involving real organisms (the details may be speculative) (1). Is the struggle for existence both necessary and sufficient for the operation of natural selection? Explain (2).

2. What is the difference between a synapomorphy (shared derived trait), a symplesiomorphy (shared ancestral trait) and a homoplasy (analogy) (2)? Give an anatomical or a molecular example of each (1)? Propose a hypothetical evolutionary explanation for your example of homoplasy (1)? Which kind of trait is more appropriate for inferring phylogenetic relationships between taxa? Explain (1).

3. What is the difference between the germline and the soma of an organism (1)? What does it mean to say that the germline and soma are separate (1)? Give an example of this separation involving a real organism (1)? How did this concept change the understanding of the evolutionary significance of the inheritance of acquired characteristics? Explain (2).

4. What is artificial selection (1)? Give a detailed hypothetical example of how you would conduct an artificial selection experiment (2). In what ways does artificial selection differ from natural selection (1)? What can artificial selection teach us about evolution (1)?

5. The fauna of an oceanic island tends to be both impoverished and unbalanced when compared to that of a continental island of the same size. Explain what this means (2) and provide one example of each underlined difference (1). Give an evolutionary explanation for the differences (2).

We strongly recommend that you practice answering these questions in full, before the test. You will have a limit of 2,750 characters (including spaces) for your essay. To give you an idea of how long that is, the full text of this announcement is 2,497 characters long. Any of the above questions is answerable in 1,000 to 1,500 characters. Note that you will not get extra points for length, or for additional examples. Indeed, if you write too much and some of it is wrong, you will lose points. Instead, focus on being as clear and succinct as possible.

Explanation / Answer

Struggle for existance is the competition between living animals for the limited resources available. Lack of food sources or limited food sources is the most general condition for struggle for existance to occur,

Natural selection is a natural process of selection of genotypes that would result in offspring with better reproductive capabilities. Natural selection is highly unpredictable and it act on pre-existing genetic variants. Observe the following examples.

Eg 1: Usually a pride of lions contains a few males and many females. For every generation, the females give several males and many female cubs. After their birth the male cubes are driven off to the pride, and then they are killed by the new male lions. It is an evolutionary advantage of the pride, because the lion cubes, which have the strong physical abilities, they can save themselves for killing.   

Thus, the lion cubs, which have strong genes (alleles) are survived, and pass their genes to next generation. Hence, the population have only Good gene pool. This is an act of natural selection and struggle for existaece between two sexes.

Eg 2: Some organisms give birth to more offspring (Eg: fish lays millions of eggs in a year), the limited availability of resources make them compete for resources and many of the are catched by predators, which is nothing but an act of struggle for existence and survival of the fittest.

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