Natural and Sexual Selection in Evolutionary Biology

Natural Selection

Process where organisms better adapted survive.

E. coli

Bacterium studied for citrate digestion evolution.

Potentiation

Major genomic rearrangement in evolution.

Actualization

Emergence of new function in evolution.

Refinement

Small mutations enhancing efficiency of functions.

Trinidad Guppies

Species studied for predator-driven evolution.

HP Guppies

High predator mortality leads to early maturation.

LP Guppies

Low predator mortality results in later maturation.

Skin Color Variation

Adaptation influenced by sunlight and vitamin needs.

Melanin

Pigment affecting skin color and UV protection.

Vitamin D

Essential for calcium absorption and health.

Folate

Vitamin destroyed by sunlight, crucial for health.

Historical Constraints

Past evolutionary history limits current adaptations.

Developmental Constraints

Embryonic development limits trait evolution.

Genetic Constraints

Genetic diversity restricts possible evolutionary changes.

Heterozygote Advantage

Heterozygotes have fitness benefits over homozygotes.

Sexual Selection

Selection based on mate acquisition abilities.

Sexual Dimorphism

Distinct differences in male and female traits.

Territoriality

Defending resources for reproductive success.

Female Choice

Males display traits to attract females.

Good Genes Hypothesis

Males' traits indicate genetic fitness.

Runaway Selection

Preference for exaggerated traits in mates.

Beachmasters

Dominant male elephant seals controlling mating.

Fundamental Asymmetry of Sex

Females invest more in offspring than males.

Brood Pouches

Males of seahorses carry and nurture young.

Artificial Selection

Human-directed breeding for desired traits.

English Carriers

Pigeon breed selected for specific traits.

Methodical Selection

Deliberate breeding for specific characteristics.

Unconscious Selection

Unintentional selection based on preferences.

Silver Fox Experiment

Domestication study selecting for tameness.

Genetic Drift

Random changes in allele frequencies over time.

Founder Effect

New population starts from a small group.

Population Bottleneck

Sudden reduction in population size and diversity.

Effective Population Size (Ne)

Number of individuals contributing to next generation.

Gene Flow

Transfer of alleles between populations.

Inbreeding

Mating between closely related individuals.

Inbreeding Depression

Reduced fitness due to inbreeding.

King Charles II

Example of inbreeding effects on health.

Genetic Diversity

Variety of genes within a population.

Self-Fertilization

Mating of an organism with itself.

Neural Tube Defects

Birth defects linked to folate deficiency.

Cheetah Bottleneck

Genetic homogeneity due to past population decline.

Amish Genetic Disorders

High incidence of rare disorders from founder effect.

Elephant Seal Recovery

Population growth after severe hunting bottleneck.