Chapter 5: Evolution and Biodiversity

Gene Flow (GF)

The process in which individuals move from one population to another and thereby alter the genetic compostion.

Genetic Drift

Change in genetic composition over time as a result of random mating.

Bottleneck Effect

A reduction in genetic diversity of a population caused by a reduction in size.

Founder Effect

A change in the genetic composition of a population as a result of the descending from a small number of colonizing individuals.

Ex. Amish communities 1/14 for polydactilla

Allopatric Speciation

The processs of speciation that occurs with geographic isolation.

Geographic Isolation

Physically separating a group of indiviuals of the species

Reproductive Isolation

2 groups of some species that evolved so far apart that they can no longer reproduce.

Sympatric Speciation

Evolution of one species into another without spearation.

• Common with plants who have chromosonal mutations that automatically make them a new species.

Pace of Evolution

Evolution is often very slow. Sometimes (over a couple million years) Natural selection will create new species.

• Very rapid evolution due to Artificial Selection

  -Ex. Fishing Cod, Crops.

GMOs

Organisms produced by copying genes from a species with a desirable trait and inserting them into another species.

Range of Tolerance

The limits to the abiotic conditions that a species can tolerate.

Ex. Dandelions in winter

Fundamental Niche

The ideal conditions for a species

Realized Niche

The range of abiotic and biotic conditions under which a species lives.

Niche Generalists

Species that live under a wide range of conditions

Ex. Coyote and Deer

Niche Specialist

Species that live only in a specific habitat or feed on a small group of species.

Mass Extinction

A large extinction of species over a relatively short period of time. Have been 5.

Species Richness

Number of species in a given area

Species Evenness

Relative proportion of individuals within the different species in a given area.

Microevolution

Evolution below species level

Macroevolution

Evolution that gives rise to new species, genera, families, classes or phyla

Genes

A physical location on a chromosome

Genotype

The complete set of genes

Phenotype

A set of traits expressed by an individual.

Mutation

A random change during the copying process

Recombination

The genetic process by which one chromosome breaks off and attaches to another chromosome during reproductive cell division.

Artificial Selection

The process by which humans determine which individuals breed typically with a preconceived set of traits in mind.

Natural Selection

The process by which the enviroment determins which individuals survive and reproduce. Not “survival of the fittest” but survival of the most fit to breed.