11.7.2 Succession from Natural Events

Succession

from Natural Events

By LaToya Washington

• explore the role natural hazards play in ecological succession

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We Will

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• differentiate between primary and secondary succession

• explore ecological succession that resulted from natural events

​​I Will

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Ecological Succession

​Ecosystems are constantly

changing.

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​Ecological succession is a gradual process of change and replacement of the types of species in a community. Each new community that arises often makes it harder for the previous community to survive.

Ecological Succession

"The process of succession can be seen in many different systems, ranging from the establishment of grasslands after a volcanic eruption, to the re-establishment of forests after agricultural fields have been abandoned." Emery, S. (2010).

​Over the course of succession, the number of different species present typically increases.

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An example of Secondary Succession by stages, Katelyn Murphy

Primary Succession

​​Secondary Succession

Ecological Succession

​​There are two major types of ecological succession: primary succession and secondary succession.

• begins in an area that previously did not support life

• much slower than secondary succession​ because it begins where there is no soil

• a pioneer species will make the new area

  habitable for other species​

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Primary Succession

​What are lichens?

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Lichens are a complex life form that is a symbiotic partnership of two separate organisms, a fungus and an alga.

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The dominant partner is the fungus, which gives the lichen the majority of its characteristics, from its thallus shape to its fruiting bodies.

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The alga can be either a green alga or a blue-green alga, otherwise known as cyanobacteria. Many lichens will have both types of algae.

Pioneer species break down rock into soil.

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Decomposition adds nutrients and allows more complex organisms to grow

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• occurs on a surface where an ecosystem has previously existed

• one community replaces another community that has been partially or totally destroyed

• occur in ecosystems that have been disturbed or disrupted by humans, animals, or by natural process such as storms, floods, and earthquakes​

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Secondary Succession

Ecological Succession

An example of Secondary Succession by stages, Katelyn Murphy

1. A stable deciduous forest community.

2. A disturbance, such as a fire, starts.

3. The fire destroys the vegetation.

4. The fire leaves behind empty, but not destroyed soil.

5. Grasses and other herbaceous plants grow back first.

6. Small bushes and trees begin to colonize the public area.

7. Fast-growing evergreen trees and bamboo trees develop to their fullest, while shade-tolerant trees develop in the understory.

8. The short-lived and shade-intolerant evergreen trees die as the larger deciduous trees overtop them. The ecosystem is now back to a similar state to where it began.

Multiple Choice

Which type of succession begins with a pioneer species breaking down rock?

• primary succession

• secondary succession

Multiple Choice

Which type of succession occurs when an existing community is disturbed due to some force?

• primary succession

• secondary succession

Multiple Choice

Which type of succession occurs in an area where life has previously not existed?

• primary succession

• secondary succession

Multiple Choice

Which type of succession is shown in the image

• primary succession

• secondary succession

Multiple Choice

How does diversity change through succession?

Succession typically ______ diversity during.

• increases

• decreases

Mt. St. Helens

• Mount St. Helens was the fifth-highest peak in Washington

• part of the Cascade Range

• lies 52 miles NE of Portland and 98 miles south of Seattle​

• ​formed within the past 40,000 years

• erupted on May 18, 1980, at 08:32​

On May 18, 1980, the Mount St. Helens became the largest and most destructive volcanic eruption in U.S. history. By the end of its cycle of fire and fury, 57 people had died.

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Footage of the 1980 Mount St. Helens Eruption

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Look at the images on the left.

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What do you notice?

What do you wonder?​

Multiple Choice

What type of plate boundary causes volcanos?

• convergent

• divergent

• transform

Multiple Choice

What type of succession occurred/is occurring after the eruption of Mt. St. Helens?

• primary succession

• secondary succession

Multiple Choice

Which type of succession would this area of early Earth undergo?

• primary succession

• secondary succesion