10.3 Gene Pools and Speciation

NATURE OF SCIENCE
1. Looking for patterns, trends and discrepancies
  1. Patterns of chromosome number in some genera can be explained by speciation due to polyploidy
    1. Polyploidy increases allelic diversity and permits novel phenotypes to be generated.
    2. Hybrid vigour
GENE POOL
1. A gene pool consists of all the genes and their different alleles, present in an interbreeding population
  1. Evolution requires that allele frequencies change with time in populations
    1. The Hardy-Weinberg Principle
SPECIATION
1. TOK
  1. How do paradigm shifts proceed in science and what factors are involved in their success?
    1. Punctuated equilibrium
      1. Implies long periods without appreciable change and short periods of rapid evolution
    2. Gradualism
      1. Due to divergence of isolated populations can be gradual
REPRODUCTION ISOLATION OF POPULATIONS
1. Temporal
2. Behavioural
3. Geographic
Patterns of natural selection
1. Directional
  1. One extreme of the range is better adapted
2. Stabilizing
  1. Remove extreme varieties
    1. Average birth weights of human babies
3. Disruptive
  1. Remove intermediate varieties

Resource summary

	Created by STEVE harton almost 10 years ago