Biology Evolution Concepts

Directional Selection

• Refers to natural selection where individuals with traits at one end of the phenotypic spectrum are favored.
• Results in increased survival or reproductive success for those individuals compared to others.

Disruptive Selection

• A type of natural selection where individuals at both extremes of the phenotypic curve have higher fitness.
• Favors organisms that exhibit traits that diverge from the average, promoting diversity within a population.

Stabilizing Selection

• Natural selection that favors intermediate phenotypes and acts against extreme variants.
• Helps maintain population stability by reducing variation in traits.

Homologous Structures

• Similar structures found in different species due to shared ancestry.
• Examples include similar bone structures in humans and whales, indicating evolutionary relationships.

Analogous Structures

• Body parts that perform similar functions but arise from different evolutionary origins.
• An example includes the wings of birds and insects, which serve the same function but have different structures.

Vestigial Structures

• Structures that exist in organisms but no longer serve their original purpose.
• Examples include the human appendix and whale pelvic bones, remnants of evolutionary history.

Convergent Evolution

• Occurs when unrelated species independently evolve similar traits due to adapting to similar environments.
• Results in analogous structures despite no recent common ancestry.

Divergent Evolution

• The process where closely related species evolve different traits adapting to varied environments.
• Leads to homologous structures among these species as they adapt differently over time.

Coevolution

• A reciprocal evolutionary process where two species influence each other's adaptation and evolution.
• Common in predator-prey relationships and mutualistic interactions between species.

Artificial Selection

• The intentional breeding of organisms with desirable traits by humans.
• Results in offspring that consistently exhibit selected traits, often seen in agriculture and pet breeding.

Natural Selection

• A foundational mechanism of evolution where organisms better adapted to their environment survive and reproduce.
• Drives the evolution of species over time, favoring advantageous traits.

Sexual Selection

• A form of natural selection based on mate choice and competition, influenced by heritable traits.
• Traits favored in this selection may enhance mating success rather than survival.

Order of Classification

• The hierarchical structure of biological classification includes: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
• Organizes and categorizes living organisms based on shared characteristics.

Gene Flow

• The movement and exchange of alleles between populations.
• Can introduce new genetic variation, impacting evolution and adaptation.

Bottleneck Effect

• A form of genetic drift occurring when a population's size is drastically reduced, often due to a natural disaster.
• Results in a loss of genetic diversity and a gene pool that may not represent the original population.

Founder Effect

• A genetic drift phenomenon where a small group from a larger population establishes a new population.
• This new population's gene pool may differ significantly from the original group, often leading to reduced genetic diversity.

Mutation

• A change in an organism's DNA sequence, which can result in new traits.
• Mutations are a primary source of genetic variation and can drive evolution.

Camouflage

• Adaptations that allow organisms to blend in with their surroundings, enhancing survival.
• Effective camouflage can protect species from predators by reducing visibility.

Mimicry

• The ability of one organism to resemble another, often harmful species.
• Provides an evolutionary advantage by deterring predators through mistaken identity.

Reproductive Success

• Refers to the likelihood that an individual will produce fertile offspring that survive to reproductive age.
• A key measure of fitness in evolutionary biology, influencing population dynamics and evolution.