biodiversity and evolution

Evolution

The relative change in genetic traits of populations that occurs over successive generations.

Microevolution

Gradual change in allele frequencies in a population over time.

Macroevolution

Large-scale evolutionary changes including the formation of new species or other taxa.

Adaptation

A structure, behaviour, or physiological process that helps an organism survive and reproduce in a particular environment.

Structural Adaptations

Physical features on an animal that have evolved over time to help them survive and breed.

Behavioural Adaptations

Changes in behavior that certain organisms or species use to survive in a new environment.

Physiological Adaptations

Metabolic or physiological adjustments within the cell or tissues of an organism in response to an environmental stimulus.

Variation

A visible or invisible difference among some members of a population.

Sexual Reproduction

A source of variation involving the passing down of hereditary information (genes) from parents to offspring.

Crossing Over

A process that occurs during meiosis where homologous chromosomes exchange genetic material to increase genetic variation.

Mutations

Sources of variation caused by changes in DNA that can be passed down to succeeding generations.

Natural Selection

The process through which populations of living organisms adapt and change, favoring individuals with adaptive traits.

Stabilizing Selection

A form of natural selection that favors an intermediate phenotype and acts against extreme versions.

Directional Selection

A form of natural selection that favors one extreme phenotype over the other.

Disruptive Selection

A form of natural selection that favors extreme phenotypes over intermediate phenotypes.

Industrial Melanism

An evolutionary effect where dark pigmentation has evolved in environments affected by industrial pollution.

Horizontal Genetic Transfer

The transfer of genes between bacteria that allows for rapid spread of antibiotic resistance.

Inheritance of Acquired Characteristics

Lamarck's concept that traits acquired during an organism’s lifetime can be passed down to offspring.

Speciation

The formation of new species due to reproductive isolation or other barriers.

Geographical Barrier

A physical feature that separates populations and prevents them from interbreeding.

Biological Barrier

Features that keep different populations reproductively isolated, even when they exist in the same geographic area.

Gene Pool

The sum of all alleles for all the genes in a population.

Genetic Drift

Change in allele frequencies in a small breeding population due to chance events.

Hardy-Weinberg Equilibrium

Condition in which allele frequencies remain constant over time, indicating no evolution.

P2 + 2pq + q2 = 1

The equation used to calculate genotype frequencies in a population.

Allele Frequency

The rate of occurrence of a particular allele in a population with respect to a particular gene.