ANT-1 Lecture Notes - Lecture 19: Peppered Moth, Mutation, Deme
Keenan Lieu
Fall 2019
Physical Anthropology
Genes and Their Evolution: Population Genetics
Demes, Reproductive Isolation, and Species
1. Evolution is about groups of potentially reproducing organisms.
2. Deme refers to members of a species that produce offspring.
3. All the genetic material within a population is referred to as the gene pool.
4. The term species refers to the populations and their members that are capable of breeding
with each other and producing viable, fertile offspring.
1. Species are defined on the basis of reproductive isolation.
5. Population genetics studies change over time (or the lack of it) in gene pools.
Hardy-Weinberg Law: Testing the Conditions of Genetic Equilibrium
1. It is a method for studying genetic change in populations.
2. If no change is occurring within the population, gene frequencies at a locus remain the
same.
3. If change is occurring, evolution is happening within the population.
Mutation: The Only Source of New Alleles
1. Mutation is the only source of new genetic information.
2. Mutation can be any heritable change in the structure or amount of genetic material.
3. Different types
1. Point, frameshift, transposable elements
4. Spontaneous mutations have no known cause.
5. Induced mutations are caused by environmental agents (mutagens).
6. Most mutations are harmless.
Natural Selection: Advantageous Characteristics, Survival, and Reproduction
1. Based on Darwin's principle that individuals with advantageous characteristics will survive
and reproduce in higher numbers (reproductive success)
2. Patterns of Natural Selection
1. Directional selection favors an extreme form of a trait.
2. Stabilizing selection favors the average form of a trait.
3. Disruptive selection favors individuals at both extremes.
3. Natural Selection in Animals: The Case of the Peppered Moth and Industrial Melanism
1. The peppered moth is the best evidence of natural selection documented.
2. The peppered moth was found in England.
3. The peppered moth had two forms: light and dark.
