Biological Succession

TEKS:

  • 7.10C observe, record, and describe the role of ecological succession such as in a microhabitat of a garden with weeds.

Introduction:

The environment is constantly changing as a result of human disturbances, like farming and construction, or natural disturbances, like fires, tsunamis, and volcanic eruptions. When these disturbances occur, they often destroy nearby ecological communities. Fortunately, these communities can often recover and establish a new community. In the two pictures below, you see an abandoned community being taken over by plants (left picture) and the establishment of a new plant community on Mount St. Helens following a volcanic eruption (right picture).

Neighborhood.jpg St._Helens.jpg
When living organisms begin to invade an area without life or an area that once supported life, it is known as succession. Succession is also a word used to describe the transfer of power in government; for example, during royal succession a prince or princess will replace a king or queen. There are two type of succession: primary and secondary (see diagrams below). During primary succession, a new community of organisms is established in a place where none existed before. In contrast, secondary succession describes the replacement of a natural community with a new one due to some type of disturbance. An area of land or water may undergo secondary succession many times; it’s just like cycle. In both types of succession, pioneer species initiate or start the community, which will eventually stabilize. Once the community stabilizes or reaches an equilibrium, it will change very little and be classified as a climax community.

Primary_Succession.png

Secondary_Succession.png



Vocabulary:

  • Climax Community: A community of plants or animals that has reached equilibrium or remains mostly unchanged following succession;
  • Pioneer Species: The first organisms to inhabit an area after a disturbance; they help break down rocks and form soil; examples are lichens and mosses.
  • Primary Succession: The establishment of a new community where none had existed before; no soil is present.
  • Secondary Succession: The reestablishment of a new community following a disturbance that wiped out most organisms from the original community.


Activities: Read the instructions carefully before beginning each activity.