1. Changes in Ecosystems: Ecological Succession

2. What is Ecological Succession?
Natural, gradual changes in the types of species that live in an area
Can be primary or secondary
The gradual replacement of one plant community by another through natural processes over time

3. Primary Succession Begins in a place without any soil:
Sides of volcanoes
Landslides
Flooding
First, lichens that do not need soil to survive grow on rocks
Next, mosses grow to hold newly made soil
Known as PIONEER SPECIES

4. Pioneer Species
Low, growing moss plants trap moisture and prevent soil erosion
Lichens break down rock to form soil.

5. Primary Succession
Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces
When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil

7. Primary Succession
Simple plants like mosses and ferns can grow in the new soil

8. Primary Succession
The simple plants die, adding more organic material (nutrients to the soil)
The soil layer thickens, and grasses, wildflowers, and other plants begin to take over

9. Primary Succession
These plants die, and they add more nutrients to the soil
Shrubs and trees can survive now

10. Primary Succession
Insects, small birds, and mammals have begun to move into the area
What was once bare rock, now supports a variety of life

11. Secondary Succession
Begins in a place that already has soil and was once the home of living organisms
Occurs faster and has different pioneer species than primary succession
Example: after forest fires

14. Climax Community
A stable group of plants and animals that is the end result of the succession process
Does not always mean big trees
Grasses in prairies
Cacti in deserts

15. How ecosystems change? Seasonal changes can affect ecosystems.
All organisms depend on resources from their environment for survival.
Climate Change – Drastic changes to the Earth’s temperatures over many years.
Miami (top)
Chicago (bottom)
Stable temperature.
Rainy season vs dry season.
How does this season change affect the animals?
Chicago—animals have spring coming although there is fairly stable temperatures.
Plants do not do well in winter, no resources for animals. Therefore, the animals hybernate, suffer through having little food, or migrate.

16. How ecosystems change? Natural disasters can affect ecosystems.
Earthquakes
Volcanoes
Hurricanes
Tornadoes
Wild Fires
Floods/Storm surges
Mount St. Helens eruption destroy entire ecosystems. 32 years later is all back.
What happens when there is a fire in the Everglades? Do you think that fires have a negative effect on the Everglades? Why?
Neg: Kills plants, destroys forest.
Positive: Burns weeds that do not allow necessary plants to grow. Before these weeds grow back, plants in these areas can sprout seeds and grow to re-take over this niche that they were competing for. These fires are a natural part of an enviornment. Organisms in these ecosystems have been able to respond to these natural disasters. They are able to come back.
Why do wild fires in California destroy so much?

17. How ecosystems change? Human intervention can affect ecosystems.
Urban development
Oil spills
Canals in Miami (diverging water from the Everglades)
Land Fills
Deforestation
Which one is easier for ecosystems to return from: human intervention or natural disasters?
Which one is easier for ecosystems to return from: human intervention or natural disasters?
SWBAT understand that organisms have bounced back from natural disasters for millions of years. Human intervention is unnatural. Ecosystems have not evolved adaptations to human intervention.
EX: Yellowstone National Park. 1900s US Gov decided wolves are bad for the ecosystem bc the farmers in the area of Yellowstone (Idaho?) thought the economy of the state was affected negatively by the wolves’ predation on the cattle. All of the wolves were hunted by man and removed.
What happened to the ecosystem? The deer overpopulated the land, and the vegetation suffered. Disease, overpopulation, and more consumption of the farmlands.
1980s pact from Canada and brought the wolves back
In 2012 there are none of the disease and overpopulation issues bc the wolves have stabilized the deer population.

18. How are succession communities different?
Pioneer Community
Climax Community
Harsh environment.
Biomass increasing.
Energy consumption inefficient.
Some nutrient loss.
Low species diversity.
Fluctuations common
Little stability
Most favorable environment.
Biomass stable.
Energy consumption efficient.
Nutrient cycling.
High species diversity.
Fluctuations do not usually occur.
Great stability.