levo

Ecosystems

Succession and local ecosystems

  • 3 things to know
  • A2 Unit 4

Overview

Ecological succession, pioneer species and how lichens make a rock surface habitable for later species.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Key term

Distinguish primary from secondary succession.

Key term

Define a sere.

Key term

Name the four named seres and the surface each starts on.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Define ecological succession.

    Model answer

    Succession is the sequence of changes in the plant and animal community of an area over time as one group of species replaces another.

  2. 2

    Distinguish primary from secondary succession.

    Model answer

    Primary succession begins on newly exposed ground with no soil, while secondary succession begins where soil and seeds remain after a disturbance.

  3. 3

    Define a sere.

    Model answer

    A sere is the complete sequence of communities in a succession from bare ground to the climax.

  4. 4

    Name the four named seres and the surface each starts on.

    Model answer

    A lithosere on bare rock, a psammosere on sand, a hydrosere in fresh water and a halosere in salt water.

  5. 5

    What is a pioneer species?

    Model answer

    A pioneer species is the first to colonise bare ground, tolerating harsh conditions and beginning the process of soil formation.

  6. 6

    Give two adaptations of a pioneer species on bare rock.

    Model answer

    Tolerance of drought and extreme temperature, and the ability to obtain nutrients directly from rock or the air rather than from soil.

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