Ap Bio Chapter 23

1649 Words Feb 16th, 2012 7 Pages
Chapter 23 Reading guide
1. what is the smallest unit of evolution and why is this important to understand? The population is the smallest unit of evolution . This is important to understand because it keeps clear what is evolving.
2. Define the following terms:
a. Microevolution: evolutionary change below the species level; change in the genetic makeup of a population from generation to generation. It is evolutionary change on its smallest scale
b. Population: a localized group of individuals that belong to the same biological species, capable of interbreeding and producing viable offspring.
c. Population genetics: the study of how populations change genetically over time.
d. Gene pool: the total aggregate of genes in a
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This helps a population making all individuals a little be different because then if there is a problem such as a disease. There is a better chance that the disease will only affect a small portion of the population. This alters every ones phenotypes.
10. What is the relationship between mutation rates and generation span? The mutation rates rise as the generation spans decrease. In animals and plants, there is only about one mutation in every 100,000 genes per generation.
11. Define the following: Genetic drift: unpredictable fluctuations in allele frequencies, reduces genetic variation over time through such losses of alleles
Bottleneck effect: when environmental change greatly reduces a population, the ratio of genes is mixed up. Certain alleles may be over/underrepresented among the survivor. Usually occurs from a natural disaster.
Founder effect: isolated individuals of a population establish a new population → limited gene pool
Gene flow: genetic additions and/or subtractions from a population resulting from the movement of gametes
12. Why would we discuss adaptive evolution and what role does natural selection play? Adaptive evolution is what allows organisms to live in changing environments. Adaptations are the result of natural selection. Natural selection allows organisms to adapt to changing environments so they can benefit from an environment.
13. Give examples of phenotypical variation that is not inheritable. A…