Chapter 32 – Human Impacts on the Environment: Key Vocabulary

Set of vocabulary flashcards summarizing major concepts, terms, and factors related to human impacts on biodiversity, extinction, and conservation.

Biodiversity

The variety and variability of genes, species, and ecosystems within a given area.

Genetic Diversity

The number of different genes and alleles present within a species.

Species Diversity

The number of different species present in an ecosystem.

Ecosystem Diversity

The variety of ecosystems within a geographic region.

Latitudinal Biodiversity Gradient

The inverse relationship in which species richness declines as latitude increases away from the equator.

Solar Energy Availability

Amount of sunlight in an area; greater energy supports higher species richness.

Evolutionary History of an Area

Length of time without major climatic disturbance, allowing communities to diversify.

Rate of Disturbance

Frequency of habitat disruption; intermediate disturbance often maximizes species richness.

Mass Extinction

Large‐scale species loss driven by catastrophic events or ‘bad luck’ rather than poor survivability.

Background Extinction

Ongoing, natural loss of species resulting from biological traits that limit survivability.

Geographic Range

Area over which a species is distributed; restricted ranges raise extinction risk.

Local Population Size

Number of individuals in a population; smaller sizes face higher extinction probability.

Habitat Tolerance

Breadth of environmental conditions a species can endure; narrow tolerance increases extinction risk.

Dodo

Flightless island bird driven to extinction by restricted range, small population, and human impacts.

Current Mass Extinction

Human‐driven global biodiversity crisis primarily caused by habitat destruction and other factors.

Habitat Destruction

Conversion or degradation of natural environments, reducing species ranges and populations.

Deforestation

Large‐scale removal of forests, diminishing biodiversity and carbon storage capacity.

Old-Growth Forest

Ancient, minimally disturbed forest with high biodiversity and large carbon sink potential.

Carbon Sink

Reservoir, such as forests, that absorbs and stores atmospheric carbon dioxide.

Reforestation

Planting new trees to restore forested areas and partially offset deforestation impacts.

Invasive Species

Non-native organisms introduced by humans that proliferate and damage native ecosystems.

Limiting Factors

Environmental variables that restrict population growth; often lacking for invasive species.

Acid Rain

Rain containing H₂SO₄ and HNO₃ from fossil-fuel emissions, harming plants and aquatic life.

Chlorofluorocarbons (CFCs)

Synthetic chemicals that break down atmospheric ozone when released.

Ozone Layer Depletion

Reduction of stratospheric ozone, increasing UV radiation reaching Earth’s surface.

Ozone Hole

Seasonal region of severe ozone thinning, notably over Antarctica.

Ecological Succession

Gradual change in species composition of an ecosystem following disturbance.

Restoration Ecology

Field focused on assisting recovery of degraded ecosystems.

Endangered Species Act (1973)

U.S. law that protects threatened and endangered plants and animals.

Flagship Species

Charismatic species used to rally public support for conservation initiatives.

Keystone Species

Species exerting strong influence on ecosystem structure despite relative rarity.

Indicator Species

Sensitive organisms used to assess ecosystem health or environmental change.

Umbrella Species

Species whose conservation indirectly protects many co-occurring species due to large habitat needs.

Fragmented Habitat

Landscape broken into isolated patches, challenging effective ecosystem protection.