BIO 002 - EVOLUTION

Evolution

Evolution

Change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction.

 A group of individuals of the same species living in a particular area at the same time

Population

All alleles of a population’s genes 

Gene Pool

The percentage of any one specific allele

Allele Frequency

Differences among members of a species

Variations

If the allelic frequency stays the same over many generations.

Genetic Equilibrium

5 Mechanisms in Evolution

Non Random Mating, Mutation, Genetic Drift, Gene Flow (Migration),Natural Selection

If organisms can choose their mating partners, then the more desirable alleles will have a higher frequency in future populations

Non Random Mating

 A ____________ in a parent’s DNA could result in offspring with different alleles. Changing the allele frequency of the population.

Mutation

Occurs when the allele frequency of a population changes by chance. 

Genetic Drift

Any movement of genes from one population to another.

Gene Flow

Individuals with the best adapted phenotypes will survive and pass on their genes to the next generation.

Natural Selection

Process whereby organisms that are better adapted to their environment survive and reproduce while those less adapted fail to do so.

Selection

A biological theory that explains why organisms seem to match their environmental niches so well. 

Natural Selection

Process of intentional or unintentional modification of a species through human actions that encourage the breeding of certain traits over others.

Artificial Selection

He proposed the theory of natural selection in his publication, on the origin of species

Charles Darwin

Term describes how successful an organism has been at passing on its genes. Has a great influence on which trait will be passed on to the next generation.

Fitness

Favors intermediate variants. The intermediate states become more common and each extreme variation will become less common or lost

Stabilizing Selection

Favors individuals at both extremes of a characteristic range

Disruptive Selection

Occurs when a certain allele has greater fitness than others resulting in an increase in the frequency of that allele until it is fixed in the population gene pool.

Directional Selection

Special kind of selection that acts on traits that help animals increase their chances of mating

Sexual Selection

Many different phenotypes found in a population, each group represents a morph (form)

Polymorphism

5 types of natural selection

Stabilizing Selection, Disruptive Selection, Directional Selection, Sexual Selection, Polymorphism

Negative Effects of Artificial Breeding

1. It removes variation in a population.

2. Organisms can be susceptible to disease or changes in the environment.

Choosing to breed plants and animals because they have desirable characteristics 

Selective Breeding