20.3 Sharing the Biosphere Flashcards
What 5 factors contribute to evolutionary change?
Mutations Gene Flow Non-Random Mating Genetic Drift Natural Selection
What is a Chromosomal Mutation?
When a piece of a chromosome is lost or shuffled around
What is a Gene Mutation?
Chemical changes in the gene when the nucleotide sequence is altered
What is Gene Flow?
When genes are added or removed from the population by the migration of individuals
What is Non-Random mating?
When mates are chosen based on physical and behavioral traits or inbreeding
What is Genetic Drift?
Loss of genes from a population due to failure of all individuals to reproduce
What is the founder effect?
When a population is established by only a few individuals
What is the Bottleneck Effect?
When a population is reduced by a severe environmental event and the gene frequencies are changed
What is Stabilizing Selection?
Occurs in stable environment when the environment maintains a constant gene pool by selecting against extremes
What is Directional Selection?
When an environment suddenly changes and a particular variation provides better adaptation to new conditions
What is Disruptive Selection?
Selects extremes when the environment changes suddenly against the norm
What is Geographic Isolation?
When physical barriers separate two population
What is Reproductive Isolation?
Occurs when individuals in a population show some variation which prevents their interbreeding
What are Seral Communities?
Intermediate stages as the community changes
What is a climax community?
The final community in succession it is diverse and stable
