Biology 106 Dr. Dudash

Study Questions Fall 1999

Study Questions Set #5 - Handed out Oct. 11, 1999.

Due: In Lab the following week.

All answers MUST be TYPED unless mathematical computation is needed.

Use no more than 3/4 of a page of single spaced typed text.

Please answer 3 of the following questions:

1. Explain the 2 main components of Sexual Selection.

Male-male competition where male RS is limited by assess to mates and female choice where female RS is limited by resources.

2. Explain the "Handicap Principle" and provide a clear example.

If you survive to reproduce with large expensive secondary male characteristics then you must be really fit OR A male possesses secondary trait/s that demonstrate he is exceptionally healthy/fit owing to functioning well (being successful) within a population in spite of this excessive trait. ex., Lady Amherst pheasant, stalk-eyed flies.

3. Draw figures illustrating the 3 common modes of speciation and the relative physical scale in which they occur. Be sure to explain the figures so that we are sure that you understand what you are talking about.

sympatric - a few meters

parapatric - 10s of meters

allopatric or geographic - kilometers

4. Discuss one major type of reproductive isolation and provide a clear example.

post zygotic - utilized in initial contact between species, more costly since gametes are wasted.

-zygotes do not develop normally

-if develop normally then they are sterile

- less fit individuals produced

prezygotic - favored by NS after secondary contact, less costly since does NOT waste gametes

ecological isolation - two potentially interbreeding species (breeding season does overlap) found in the same area but occur in different microhabitats

temporal isolation - mate at different times even though occur in the same area

behavioral isolation - species specific

mechanical isolation - structural differences between species that prevent copulation

5. What is phyletic gradualism ? and if Darwin were alive today would he support it?

Phyletic gradualism refers to the rate of speciation being overall a gradual process. It is proposed to occur through steady anagenetic (directional) change within a lineage. It is supported by evolutionary biologists (Dobzhansky and Simpson) who support Darwinian processes as the underlying mechanism of all change . There is no need to invoke a speciation event with each evolutionary change. YES, Darwin would support this idea.