Have a seat and take out your notebooks. Mr. S and I will pass out a study guide.

Transcription

1 Today s Topic Evolution: Cosmos Extinction Learning Goal: SWBAT differentiate between primary and secondary succession, and predict how a community will return to a state of equilibrium. Have a seat and take out your notebooks. Mr. S and I will pass out a study guide.

2 Homework Complete the Simulating Adaptations Lab (One Day Late) Complete cattle, cows, and dogs articles. (Four Days Late)

3 Upcoming Test Our next test will take place on Friday, 4/17. It will cover all of Evolution: Biological Evolution Natural Selection Artificial Selection Adaptations Extinction Succession

4 After the Disasters What percentage of life constitutes a mass-extinction event? What happened during the Cretaceous-Paleogene extinction event? How does the world even begin to recover after such a horrible catastrophe?

5 After the Disasters The answer lies within Ecological Succession. Ecological succession refers to the somewhat predictable series of changes over time that a community will experience after a disturbance.

6 CrashCourse Video To help introduce this idea, we are going to watch a ten-minute episode of CrashCourse. Please pay attention to the following: 1. What historical error does the presenter make? 2. The following terms: Disturbance, Ecological Succession, Primary Succession, Pioneer Species, Secondary Succession, Climax Community

7 What is a Disturbance? To set off the entire process of succession, a destructive event needs to a occur or a disturbance. A disturbance is any change in a community s environment, large or small.

8 Examples of Disturbances A community may experience natural or human-caused disturbances such as: Climate Change Storms Floods Fire

9 Succession Prior to a disturbance, a community may be in a state of equilibrium (stable and balanced.) Characteristics such as limiting factors hold the community at its carrying capacity. However, a disturbance will throw the community into disequilibrium, forcing the community to adjust.

10 Types of Succession There are two types of succession, one more severe than the other: Primary Succession Secondary Succession

11 Primary Succession When a disturbance is so severe that no vegetation or soil life remains, primary succession occurs. In primary succession, a community restarts itself from scratch. It occurs after a large expanse of rock, sand, or sediment is exposed for the first time.

12 Primary Succession Some causes for primary succession to occur are: Glacial Retreat

13 Primary Succession Some causes for primary succession to occur are: Lakes Drying Up

14 Primary Succession Some causes for primary succession to occur are: Volcanic Lava or Ash Spreading

15 How to Primary Succession: Step 1: Pioneer Species To start the rebuilding process, you will need a pioneer species. A pioneer species is a species that is the first to colonize newly exposed land. They are normally very well adapted for colonization.

16 How to Primary Succession: Step 1: Pioneer Species Pioneer species tend to have spores or seeds that can travel long distances. Examples: Lyme Grass

17 How to Primary Succession: Step 1: Pioneer Species Examples: Green Algae

18 How to Primary Succession: Step 1: Pioneer Species Examples: Lichen

19 Primary Succession: Step 2 Get Tiny Plants Lichens, for example, excel at breaking down the surface of rocks which creates soil. From this soil, small plants will begin to form.

20 Primary Succession: Step 3 Get Tiny Insects As the small plants begin to grow, small insects and worms will begin to move in.

21 Primary Succession: Step 4 Thrive! As new organisms arrive, they will continue to change the environment by providing more nutrients and habitat for future arrivals.

22 Primary Succession: Step 4 Thrive! As time passes, larger plants establish themselves, the amount of vegetation increases, and species diversity increases.

23 Secondary Succession In secondary succession, a disturbance dramatically alters an existing community, but it does not destroy all living things or organic matter in the soil. Some of the soil from the previous ecosystem remains. As a result, secondary succession occurs faster than primary succession.

24 Secondary Succession Some causes for secondary succession to occur are: Fires

25 Secondary Succession Some causes for secondary succession to occur are: Logging

26 Secondary Succession Some causes for secondary succession to occur are: Farming

27 Secondary Succession Because preexisting soil exists in the community, secondary succession is much faster.

28 In The End Once a community transitions back to a state of equilibrium, the succession will lead to a climax community. A climax community is a stable community that completes the succession process.

29 Climax Community The organisms that will thrive in a climax community are determined by the climate, soil, and other factors.

30 Climax Community However, just because a community arrives to its climax state does not guarantee that it will always get there again if a disturbance occurs.