Evolution

Darwins Theory

All species originated from existing species and that the process by which species came into existance was what he called natural selection.

Lamarcks Theory

Organisms evolve by passing on physical traits acquired during their lifetime to their offspring.

Adaptation

Beneficial traits that increase fitness in an environment that will increase survival and pass those traits to offsprings.

V.I.D.A

Variation, Inheritance, Differential Survival and Reproduction, and Adaptation

Variation

Individuals in a population differ for a particular trait that already exists. Variation originates from mutations.

Inheritance

The variation must be inherited from parent to offspring through genes.

Differential Survival and Reproduction

When more offsprings are produced than the environment can support, so organisms compete for resources, and with individuals with more beneficial traits are more likely able to survive and repoduce (Fitness).

Artifical Selection

Nature provides the inherited variations and humans select those variations they find useful.

Natural Selection

Organisms that have favorable traits for a particular environment survive and reproduce, thus passing on those traits for future generations and 4 conditions need to occur: V.I.D.A.

Fitness

The ability to survive and reproduce. When a popuation competes for resources, the beneficial traits are more likely to survive and reproduce.

Gene Pool

The sum of all genetic information of all individuals in a population.

Allele Frequency

The measure of how common a certain allele is in a population.

Hardy-Weinburg Equilibrium

A null model stating the relationship between alleles, genotypes, and phenotypes frequencies are constant. HWE assumes NO! (The population isn’t evolving)

Microevolution

When an oberservable change in allele frequency occurs in a population.

5 fingers of evolution

Genetic Drift (Small Population), Sexual Reproduction, Mutations, Gene Flow, and Natural Selection

Founder’s Effect

Genetic diversity is lost when a small subset of the population leaves to form a new population.

Bottleneck Effect

Genetic diversity is lost when the environment causes a sharp decline in population.

Directional Selection

Individuals that display a more extreme form of a trait have greater fitness than individuals with an average form of the trait.

Stabilizing Selection

Individuals with the average form of a trait have the highest fitness.

Disruptive Selection

Individuals with either extreme variation of a trait have greater fitness than individuals with the average form of a trait.