Ecological Succession and Ecosystem Stability

Flashcards about ecological succession, primary and secondary succession, cyclical succession, climax communities, and human impact on ecosystems.

What is ecological succession?

Ecological succession is the change over time in the species that live in an area, triggered by changes in abiotic (non-living) and biotic (living) factors.

What is the difference between primary and secondary succession?

Primary succession occurs when new land is created, and a series of communities emerge; secondary succession occurs when an existing ecosystem is drastically altered, and the remains of the previous ecosystem are used.

What is the role of soil in primary and secondary succession?

Primary succession begins with no soil, while secondary succession starts with soil already present.

What are pioneer species?

Lichens and mosses, which are photosynthetic and don't grow root systems, are often the first living organisms to appear in primary succession.

Describe cyclical succession in ecosystems.

Succession often leads to cyclical patterns with growth of thorned brush, tree growth for herbivore protection, die-off of trees, and return to pasture.

What is a climax community?

A stable community formed at the end of ecological succession, determined by the environmental conditions of the area.

How do human influences affect climax communities?

Removing forests for livestock grazing and draining wetlands for development.

List seven requirements for healthy and sustainable ecosystems

Healthy ecosystems require the capability to change gradually, a constant supply of energy, the ability to recycle nutrients, a stable climate, genetic diversity, keystone species, freedom from human interference, and sustainable resource harvesting.

How do humans threaten the sustainability of ecosystems?

Depletion of natural resources and lowering genetic diversity are examples of how humans threaten the sustainability of ecosystems.

What are the typical characteristics of primary succession progression over time?

Increasing species diversity, plant size, primary production, food web complexity, and nutrient cycling.