Exam #2 key terms

Natural Selection

The process through which adaptive traits are favored and become more common in a population.

Adaptive Traits

Traits that improve the chances of survival and reproduction in a particular environment.

Differential Success

The concept that individuals with favorable traits are more likely to survive and reproduce.

Mendelian Traits

Traits that are determined by a single gene and follow Mendelian inheritance patterns.

Polygenic Traits

Traits influenced by multiple genes, resulting in a range of phenotypes.

Heritability

The proportion of phenotypic variance in a population that is attributable to genetic variance.

Artificial Selection

The process by which humans select for desirable traits in organisms.

Biotic Factors

Living components of an ecosystem that affect natural selection.

Abiotic Factors

Non-living components of an ecosystem that impact natural selection.

Directional Selection

A mode of natural selection that favors one extreme phenotype over others.

Stabilizing Selection

A mode of natural selection that favors intermediate phenotypes and reduces variation.

Disruptive Selection

A mode of natural selection that favors extreme phenotypes at both ends of the spectrum.

Speciation

The formation of new and distinct species in the course of evolution.

Geographic Isolation

Physical separation of populations that leads to speciation.

Reproductive Isolation

Factors that prevent different species from interbreeding.

Morphological Species Concept

Defining species based on physical characteristics and similarities.

Biological Species Concept

Species are defined by their ability to reproduce and produce viable offspring.

Divergent Evolution

The accumulation of differences between closely related populations or species.

Convergent Evolution

The independent evolution of similar traits in different lineages.

Endothermy

The physiological ability to maintain a constant body temperature through internal heat generation.

Sexual Selection

A form of natural selection involving competition for mates.

Intrasexual Selection

Competition between individuals of the same sex for access to mates.

Intersexual Selection

Mate choice where individuals of one sex select mates based on specific traits.

Anisogamy

The difference in gamete size and investment between males and females.

Operational Sex Ratio

The ratio of males to females available for mating at a given time.

Bateman’s Principle

The concept that males usually have greater potential reproductive success than females.

Secondary Sexual Characteristics

Traits that are not directly involved in reproduction but serve to attract mates.

Sperm Competition

Competition between sperm of different males to fertilize eggs.

Good Genes Hypothesis

The theory that certain traits indicate genetic quality, influencing mate choice.

Extrapair Copulation

Mating outside a social pair bond, common in supposedly monogamous species.

Background Extinction

The gradual process of species disappearing at a relatively steady rate.

Mass Extinctions

Events that result in the widespread and rapid decrease in biodiversity on Earth.

Fossil Record

The history of life as documented by fossils, which includes evidence of extinct species.

Adaptive Radiation

Rapid evolution of diversely adapted species from a common ancestor.

Hybrid Inviability

A postzygotic barrier that occurs when hybrid offspring fail to develop properly.

Hybrid Sterility

A postzygotic barrier where hybrids are sterile and cannot reproduce.

Prezygotic Barriers

Factors that prevent mating or fertilization between species.

Postzygotic Barriers

Factors that affect the viability or reproductive capacity of hybrid offspring.

Gene Flow

The transfer of genetic variation from one population to another.

Endangered Species

Species that are at risk of extinction due to habitat loss, climate change, or other factors.

Extinct Species

Species that no longer exist anywhere on Earth.

Research Evidence

Data gathered from studies to support or refute scientific hypotheses.

Experimental Evolution

The study of evolutionary processes in controlled laboratory settings.

Digital Evolution

The study of evolutionary processes in computer simulations or models.

Biodiversity Loss

The decline of different kinds of living organisms in a particular ecosystem.

Genotypic Variation

Differences in the genetic makeup among individuals in a population.

Phenotypic Variation

Variability in traits among individuals due to genetic and environmental influences.

Evolutionary Dynamics

The changes in genetic composition of populations over time.

Galapagos Finches

A group of finches whose evolution has been extensively studied to demonstrate natural selection.

Cacti Adaptations

Specialized traits that allow cacti to survive in arid environments.

CAM Photosynthesis

A photosynthetic adaptation allowing plants to minimize water loss in dry climates.

Irreducible Complexity

The idea that certain biological systems cannot evolve by successive small modifications.

Population Genetics

The study of genetic variation within populations and the mechanisms of evolution.

Phylogenetic Trees

Diagrams that show the evolutionary relationships among species.

Speciation Event

A point in time when a new species arises from an ancestral population.

Extinction Risk

The likelihood of a species becoming extinct due to various threats.

Conservation Biology

The field of biology dedicated to protecting and preserving biodiversity.

Adaptive Trait Examples

Specific traits that have evolved to enhance survival in specific environments.

Prehistoric Extinct Species

Species that lived and disappeared before recorded history.

Evolutionary Theory

A systematic body of concepts explaining the changes in populations and species over time.