🌍 AP Environmental Science – Unit 2

Biodiversity

The variety of life at different levels — genes, species, and ecosystems.

Genetic diversity

Variety of genes within a population; more genetic diversity leads to better survival and adaptation to stressors.

Species diversity

Variety of species in an ecosystem, measured by species richness and species evenness.

Habitat (ecosystem) diversity

Variety of ecosystems/habitats in a region, such as forests, wetlands, grasslands, and deserts.

Bottleneck Effect

A sharp reduction in population size leading to the loss of many genes and reduced variation.

Founder Effect

Occurs when a few individuals start a new population, resulting in reduced genetic variation.

Niche

The role an organism plays in an ecosystem.

Fundamental niche

The full range of conditions an organism could occupy without competition.

Realized niche

The actual conditions/resources used by an organism due to competition or predation.

Specialist species

Species with a narrow niche, specific food or habitat needs.

Generalist species

Species with a broad niche, flexible diet/habitat use.

Ecosystem Services

Benefits that humans receive from ecosystems, including supporting, provisioning, cultural, and regulating services.

Disruption

Human-caused impacts that affect ecosystems, such as land-use change and pollution.

Island Biogeography

Theory explaining that biodiversity on islands depends on island size and distance from the mainland.

Invasive Species

Non-native species that spread and harm ecosystems.

Habitat fragmentation

The division of large habitats into smaller patches due to human activity.

Habitat corridors

Strips of habitat that connect fragmented patches, allowing species movement and gene flow.

Ecological Tolerance

The range of conditions an organism can survive.

Indicator Species

Species that signal the health or stress of an ecosystem.

Mass Extinction

An event in which a large number of species go extinct in a short period of time.

Survival of the Fittest (Natural Selection)

The process by which organisms best adapted to their environment are more likely to survive and reproduce.

Ecological Succession

Gradual change in species composition of an ecosystem over time.

Keystone Species

Species that have a disproportionate effect on ecosystem stability.

Foundational Species

Species that physically create or shape habitats.

Biodiversity

The variety of life at different levels
— genes, species, and ecosystems.

Genetic diversity

Variety of genes within a population; more genetic diversity leads to better survival and adaptation to stressors.

Species diversity

Variety of species in an ecosystem, measured by species richness and species evenness.

Habitat (ecosystem) diversity

Variety of ecosystems/habitats in a region, such as forests, wetlands, grasslands, and deserts.

Bottleneck Effect

A sharp reduction in population size leading to the loss of many genes and reduced variation.

Founder Effect

Occurs when a few individuals start a new population, resulting in reduced genetic variation.

Niche

The role an organism plays in an ecosystem.

Fundamental niche

The full range of conditions an organism could occupy without competition.

Realized niche

The actual conditions/resources used by an organism due to competition or predation.

Specialist species

Species with a narrow niche, specific food or habitat needs.

Generalist species

Species with a broad niche, flexible diet/habitat use.

Ecosystem Services

Benefits that humans receive from ecosystems, including supporting, provisioning, cultural, and regulating services.

Disruption

Human-caused impacts that affect ecosystems, such as land-use change and pollution.

Island Biogeography

Theory explaining that biodiversity on islands depends on island size and distance from the mainland.

Invasive Species

Non-native species that spread and harm ecosystems.

Habitat fragmentation

The division of large habitats into smaller patches due to human activity.

Habitat corridors

Strips of habitat that connect fragmented patches, allowing species movement and gene flow.

Ecological Tolerance

The range of conditions an organism can survive.

Indicator Species

Species that signal the health or stress of an ecosystem.

Mass Extinction

An event in which a large number of species go extinct in a short period of time.

Survival of the Fittest (Natural Selection)

The process by which organisms best adapted to their environment are more likely to survive and reproduce.

Ecological Succession

Gradual change in species composition of an ecosystem over time.

Keystone Species

Species that have a disproportionate effect on ecosystem stability.

Foundational Species

Species that physically create or shape habitats.

Pioneer Species

First species to colonize a barren or disturbed area (e.g., lichens, mosses). Start soil formation.

Primary Succession

Begins on bare rock (no soil). Example: after volcanic eruption.

Secondary Succession

Begins in an area with soil but disturbed (e.g., after fire or farming). Faster than primary.

Climax Community

Relatively stable, long-term community at the end of succession (often forests in many biomes).

Species Richness

Number of different species in an ecosystem.

Species Evenness

How evenly individuals are distributed among species (higher evenness = healthier ecosystem).

Anthropogenic

Human-caused effects on the environment (pollution, climate change, deforestation).

Economic Consequences

Financial impacts (cost of invasive species, disasters, loss of ecosystem services).

Ecological Consequences

Environmental impacts (loss of biodiversity, habitat degradation).

Supporting Services

Basic ecosystem processes (nutrient cycling, soil formation, primary productivity).

Provisioning Services

Goods/resources from ecosystems (food, water, timber, medicine).

Regulating Services

Ecosystem processes that regulate (climate regulation, flood control, water purification, pollination).

Cultural Services

Non-material benefits from ecosystems (recreation, tourism, spiritual, aesthetic value).