Download 20-sec.-2-Eco-Succession

BIO 9
Ch. 20 sec. 2: Ecological Succession
Read the following paragraphs and use the information to complete the tasks that follow..
Name:
The gradual, sequential regrowth of a community of species in an area is called ecological
succession. Ecologists recognize two types of succession: primary succession and secondary
sucession.
Primary succession is the development of a community in an area that has not supported
life previously, such as bare rock, a sand dune, or an island formed by a volcanic eruption.
Secondary succession is the sequential replacement of a species that follows disruption of an
existing community. The disruption may stem from a natural disaster, such as a forest fire or a
strong storm, or from human activities, such as farming, logging, or mining.
Any
new habitat is an invitation to many species that are adapted to be good pioneers. The species
that predominate early in succession—called the pioneer species—tend to be small, fast growing,
and fast-reproducing. Pioneer species are well suited for invading and occupying a disturbed
habitat. They are often very good at dispersing their seeds, which enables them to quickly reach
disrupted areas.
The traditional description of succession is that the community proceeds through a
predictable series of stages until reaches a stable end point, called a climax community.
Realistically, ecologists agree that the idea of a single successional pathway ending in a stable
climax community is too simple to describe what actually occurs in nature.
1. Secondary succession is to a forest that has been destroyed by fire as primary succession is to a
a. sand dune.
b. bare rock.
c. violent storm.
d. Both (a) and (b)
2. Insert the following characteristics into the Venn Diagram:



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Soil and nutrients already present
Brand new terrain
Climax community
Faster process
Fire, flood, tsunami
Lava flow and glaciers
Pioneer species
Progressive steps
Slower process
3.
Identify each of the following as primary or secondary succession:
4. An old house was torn down in Detroit. Small weeds and grasses grew in the vacant lot. Over the next few years, bushes
and tree seedlings began to grow.
5. An undersea volcano erupted and formed a small island. Mosses and lichens began to grow on the bare volcanic rock.
6. A logging company cut down all the large spruce trees in an area of forests. After the area was cleared, spruce seedlings
began to sprout. Rabbits, birds, and deer returned to the area.
Succession can also transform a pond into a forest, as illustrated below.
7. Name at least two pond populations that could not survive in the forest ecosystem.