Evolution

Adaptations

Inherited characteristics that increase an organism's chance of survival and reproduction in a specific environment.

Allele Frequency

How common an allele is in a population, determined by dividing the number of times an allele occurs by the total number of copies of all alleles for that gene.

Differential Reproductive Success

When certain individuals produce more offspring than others due to advantageous traits.

Evolution of Species

Changes in heritable traits within populations over successive generations, leading to the formation of new species from common ancestors.

Fitness Benefits

Advantages gained from certain traits or behaviors that increase an organism’s chances of survival and reproduction.

Heritable Variations

Differences in characteristics among individuals that can be passed down from parents to offspring.

Mutation

Any change that occurs in the DNA sequence which can lead to variations within species.

Natural Selection

A process where organisms with advantageous traits tend to survive, reproduce, and pass on these traits.

Phenotype

An individual's observable physical properties, influenced by genotype and environment.

Selective Pressure

An environmental factor that leads to changes in the frequency of traits over generations.

Artificial Selection

A process where humans intentionally breed organisms with desirable traits.

Convergent Evolution

When different species independently evolve similar traits as they adapt to similar environments.

Gene Flow

The transfer of genetic variation from one population to another.

Genetic Drift

A mechanism of evolution causing random changes in allele frequency in a population over time.

Speciation

The evolutionary process by which populations evolve to become distinct species.

Vestigial Structures

An anatomical feature that has lost most of its original function through evolution.

Cladograms

Diagrams showing relationships among organisms based on shared derived characteristics.

Phylogenetic Trees

Diagrams that represent the evolutionary relationships among various species.

Punctuated Equilibrium

A theory proposing that species exhibit little change for long periods, interrupted by brief periods of significant change.

Reproductive Isolation

The inability of different species to interbreed due to barriers.

Disruptive Selection

A type of natural selection that favors individuals at both extremes of a trait distribution.

Ecological Isolation

Occurs when species do not mate because their habitats are different.

Allopatric Speciation

Speciation that occurs when populations become geographically isolated.

Sympatric Speciation

Speciation that occurs when new species evolve from a single ancestral species while inhabiting the same region.

Gradualism

The theory that evolution occurs slowly and steadily over time.

Adaptive Radiation

An evolutionary process where organisms rapidly diversify into multiple new forms.

Emergent Diseases

New infections resulting from changes or evolution of existing organisms.

Extinct Organisms

Species that no longer exist anywhere on Earth.

Genetic Variation

Differences in genetic makeup among individuals within a population.

Fossil Record

All fossils discovered and the information derived from them about past life.

Pathogens

Microorganisms that cause disease in their host.

Geographic Isolation

When groups are separated physically from one another, preventing genetic exchange.

Rate of Extinction

The number of species that become extinct over a given period.

Rate of Speciation

The speed at which new species evolve from an ancestral species.