Evolution and Ecology Vocabulary

Flashcards covering key vocabulary terms and definitions from an evolution and ecology lecture.

Evolution

The process through which populations of organisms change over generations due to changes in gene frequencies.

Evolution Note

Individuals do not evolve; rather, the genetic makeup of the population changes over time.

Darwin’s Theory

Species evolve through a process called natural selection.

Variation

Within any population, individuals differ in their traits.

Inheritance

Many traits can be passed from parents to offspring.

Selection

Some traits improve an organism’s chances of surviving and reproducing.

Time

These beneficial traits accumulate over many generations.

Adaptation

Populations become better suited to their environment.

Lyell's Contribution

Earth is very old, giving plenty of time for evolution.

Malthus's Contribution

Populations grow faster than resources, creating competition.

Microevolution

Small changes in allele frequencies within a population.

Macroevolution

Large-scale changes that create new species over long periods.

Homologous Structures

Structures that have the same basic design but different functions, indicating common ancestry.

Analogous Structures

Structures that serve similar purposes but evolved independently.

Vestigial Structures

Body parts that have lost their original function.

Mutation

Random changes in DNA that create new genetic variation.

Natural Selection

Traits that help survival and reproduction become more common.

Gene Flow

Movement of genes between populations when individuals migrate.

Genetic Drift

Random changes in gene frequencies, especially in small populations.

Founder Effect

A few individuals start a new population.

Bottleneck Effect

A population drastically shrinks due to disaster, reducing genetic diversity.

Hardy-Weinberg Principle

Allele frequencies in a population remain constant if certain conditions are met.

Directional Selection

One extreme trait is favored, pushing the population toward that trait.

Stabilizing Selection

The average trait is favored, reducing extremes.

Disruptive Selection

Both extremes are favored over the average.

Sexual Selection

Traits that help attract mates become more common.

Artificial Selection

Humans breed plants or animals for desirable traits.

Speciation

New species form when populations become reproductively isolated from each other.

Geographic Isolation (Allopatric)

Physical barriers like mountains or rivers separate populations.

Ecological or Behavioral Isolation

Populations use different habitats or have different mating behaviors.

Biological Isolation

Genetic differences prevent successful breeding.

Prezygotic Barriers

Prevent fertilization (different mating times, behaviors).

Postzygotic Barriers

Fertilization happens but offspring are sterile or inviable.

Classification Hierarchy

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Clade

A clade includes a common ancestor and all its descendants.

Coevolution

Two species influence each other’s evolution.

Convergent Evolution

Unrelated species evolve similar traits due to similar environments.

Divergent Evolution

Related species develop different traits.

Adaptive Radiation

Rapid diversification when new habitats become available.

Gradualism

Slow and steady change over time.

Punctuated Equilibrium

Long periods of little change interrupted by rapid bursts of evolution.

Levels of Ecological Organization

individual → population → community → ecosystem → biome → biosphere.

Tundra

Cold, treeless, permafrost.

Taiga

Cold conifer forests.

Temperate Forests

Seasonal trees.

Tropical Rainforests

Hot, wet, very diverse.

Deserts

Dry, extreme temperatures.

Grasslands/Savannas

Grassy, seasonal rainfall.

Chaparral

Shrubs, dry summers, fires.

Freshwater

Lakes, rivers.

Marine

Oceans and coral reefs.

Mutualism

Both benefit (+/+).

Parasitism

One benefits, the other is harmed (+/–).

Commensalism

One benefits, the other is unaffected (+/0).

Predation

Predator eats prey (+/–).

Competition

Both species compete for resources (–/–).