1. Natural Changes in Ecosystems

2. Could this
ever turn into this?

3. Succession
Process where there is a change in the species of a community over time
Extremely gradual

4. Organisms present at one stage change the environment in some way
Create soil
Change soil conditions
This change makes it possible for some species to move in
Process repeats until new environment is formed

5. 2 types of succession… #1: Primary Succession
Gradual growth of organisms in an area that was previously empty
Ex. volcanic islands, lava flows, rocks left by glaciers

6. Pioneer species
First organisms that appear in an area
As they grow, they alter the conditions of the area
Ex. Create soil
Changes allow new plants and animals to grow and survive
Ex.
Lichens
Break down rocks into soil – allows other plants to start to grow

7. Surtsey Island Volcanic island
Pioneer species were bacteria and mosses
Other organisms – sandworts, grasses, flies, birds

8. Succession Timeline 6 environments Put in order of succession
9 organisms
In which environment do they fit?

9. Climax community
Stable community of a diverse number of species that is not easily replaced by other communities

10. Succession in a Wetland

11. #2: Secondary Succession
Gradual growth of organisms in an area that previously had a number of organisms
Ex. Regeneration of a burned forest

12. Artificial succession
Farmer ploughs his field
Field is now bare
Pioneer species are introduced when crop seeds are planted
Climax community forms when crop starts to grow

13. Pollution

14. When a substance is added to the environment at a fast rate
Substance can not be broken down or stored in a non-damaging form
Is cycled through the environment
Natural substances (eg. carbon dioxide) can also become pollutants when the amount is too high

15. Acid Rain
Occurs when pollutants containing sulfur and nitrogen are found at high levels in the air
Ex. From burning fossil fuels
Pollutants mix with water vapor creating acid rain

16. What is an acid?
pH scale measures acidity
0-6 = acid
7 = neutral (pure water)
8-14 = basic (opposite of acid)
Acid rain has a pH below 5.6

17. Effects of acid rain

20. 1908 vs. 1969

22. Pollution & the Food Web

23. Biomagnification Tag Krill – eat plankton Fish – eat zooplankton
Seal – eat small fish
Orca – eat seal
Did our game accurately model a food chain?

24. Pink tokens were not food
Mercury that had entered the environment
If you had 30% or higher, you did not survive
Where could the mercury have come from?
Which organism had the highest levels of mercury? Why?
What other top level carnivores could we substitute for the orca?

25. Biomagnification Example
Occurs when pollutants enter food web and magnify (build up) in higher level consumers
Example
Pollutants are stored in organisms in the same way that food energy is stored

26. Examples
PCBs (polychlorinated biphenyl)
Found in paints & plastic packaging materials
Break down slowly in the environment
Remains in ground and water

27. Used in old thermometers, gold mining
Mercury
Used in old thermometers, gold mining
Dissolves in water

28. DDT
Pesticide used to kill insects in the 1940s-1960s

33. Bio-Indicator Species
A species that indicates whether or not the ecosystem is healthy and balanced
Ex. Wolves, Falcons, Frogs

34. Keystone Species
Species that hold the ecological balance together in an ecosystem
Maintain the structure and integrity of the community