Unit 2 Guide: Ecosystem Resilience and Biological Succession

Natural Disruptions

Environmental consequences occurring without direct human input.

Periodic Natural Change

Occurs at regular, repeated intervals.

Episodic Natural Change

Occurs somewhat regularly but at irregular intervals.

Random Natural Change

Occurs without a regular pattern; unpredictable.

Glacial Periods

Time when water is locked in ice sheets, causing sea levels to drop.

Interglacial Periods

Warmer periods where ice melts, causing sea levels to rise.

Migration

The seasonal or long-term movement of individuals from one area to another.

Pioneer Species

The first species to colonize an area during ecological succession.

Primary Succession

Succession that occurs in an area without soil and previous life.

Secondary Succession

Succession in an area that has been disturbed but where soil remains intact.

Climax Community

The final, stable stage of ecological succession.

Keystone Species

A species on which other species in an ecosystem largely depend.

Indicator Species

An organism whose presence reflects a specific environmental condition.

Soil Formation

A defining characteristic of primary succession, occurs when pioneer species weather substrates.

Ecosystem Disruption

Events that create or destroy habitats, affecting biodiversity.

Ecological Succession

The gradual replacement of one group of species by another over time.

Impact of Natural Disruptions

Natural disruptions can create diverse habitats and increase biodiversity.

Forest Fires

A type of disturbance that can lead to secondary succession.

Volcanic Eruptions

A primary succession event that creates bare rock.

Fossil Records

Evidence used to analyze past climate fluctuations.

Climate Fluctuations

Long periods of warming and cooling in Earth's history.

El Niño

An episodic natural phenomenon that affects climate cycles.

Wet and Dry Seasons

Periodic climatic changes occurring annually in the tropics.

Glacial Retreat

A process that initiates primary succession by exposing bare rock.

Habitat Alteration

Changes in ecosystems due to natural disruptions.

Biodiversity Increase

The result of periodic disturbances creating new habitats.

Public Misconceptions about Disruption

Assuming all disruptions are negative; many are necessary for ecosystem health.