Geology 105 - Paleontology
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Natural Selection

Reading: UC Museum of Paleontology Web Site

The reading for this unit is here:

Evolution 101 (UC Museum of Paleontology)

Read chapters of Evolution 101 called #1) An introduction to evolution; #3) Mechanisms: the processes of evolution and #4) Microevolution.



gametes - sexual reproduction cells: sperm and eggs
altruism - self-sacrificing behavior towards other individuals; behavior that benefits another organism at some cost to the individual
proxy - a stand-in for a different variable that is difficult to measure directly. For example, right plumage on a bird can be an indirect measure of health.
speciation - the production of new species


Key Concepts and Questions:

1. What's the difference between evolution and natural selection?

Find definitions for evolution and natural selection:



natural selection:




2. What are the necessary conditions for natural selection to occur?

A. There must be variation within the population.



In lecture we will add a couple more mechanisms for variation.






B. The variation must be heritable - organisms must be able to pass on the variation to their offspring.






C. The variation must be change the liklihood of either survival or successful reproduction.





3. Evolutionary change without natural selection





5. Some apparently puzzling evolutionary patterns

Use the readings on sexual selection and kin selection to explain why natural selection might lead to these phenomena:

Male deer grow very large antlers that they drop and regrow each year. The antlers are very "expensive" for the deer to grow - a deer that is healing from a major injury or that has been ill will grow stunted antlers (the Biology Dept. has a great display of funky antlers in SQU 105). The antlers are not typically used for self-defense (deer use their hoofs on prospective predators) but are only used for ritual combat with other males. Why would deer evolve the growth of such an expensive frill?




Within a wolf pack, typically only a single pair - the alpha male and female - mate. The entire pack raises the resulting pups, hunting for them and defending them against predators. Why would a wolf invest its energy and put itself at risk for another wolf's pup?



We will do a variety of other puzzling situations in class.


1. Short Answer

2. Essay