Community ecology

1. Community ecology

2. Interactions When organisms live together in ecological communities, they interact constantly. Community interactions, such as competition, predation, and various forms of symbiosis, can affect an ecosystem.

3. Niches • What is included in an organism’s niche? • Range of temperatures necessary for survival • Position in food web • Time of year it reproduces • Type of shelter it occupies • No two species can share the same niche in the same habitat. • Different species can occupy niches that are very similar.

4. Symbiosis Any relationship where two organisms are living closely together.

5. Competition When organisms of the same or different species attempt to use an ecological resource in the same place at the same time. Great White Shark Competition Video

6. Competitive Exclusion principle • Resources are limited. • No 2 species can occupy the same niche in the same ecosystem at the same time. • Direct competition will result in a winner and loser. The loser will fail to survive.

7. Exception The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree.

8. Predation • An interaction in which one organism captures and feeds on another organism is called predation. • The organism that does the killing and eating is called the predator, and the food organism is the prey. Praying Mantis Predator Video

9. Commensalism A symbiotic relationship where one organism benefits and the other is neither benefited nor harmed. Dust Mites on Eyelash

10. Mutualism A symbiotic relationship where both organisms benefit mutually. Ants and acacia tree Clown fish and sea anemone

11. Parasitism A symbiotic relationship where one organism benefits and the other suffers. Wasp parasite on caterpillar Zombie Brain Snail Parasite Video Birds use another host to raise their young & kill that host’s eggs

12. Antipredator adaptations (crypsis) • Disruptive Coloration • Animals, like the zebra, use their coloration patterns to make it hard to see them. • Counter Shading • Counter shading is seen mostly in aquatic animals. They are light on the bottom and dark on the top.

13. Antipredator adaptations (crypsis) • Color Change • Some animals can even change their coloring to try and fool predators. • Camouflage (appropriate background) • Another group of animals look like something commonly in their environment.

14. Antipredator adaptations (crypsis) • Warning Coloration • Animals that are poisonous often advertise this by using bright colors and patterns to discourage predators. • Mimicry • An organism copies the crypsis of another more dangerous organism

15. Ecological Succession

16. What is ecological succession? • Predictable changes that occur in a community over time. • Ecosystems are constantly changing in response to natural and human disturbances. • Older inhabitants gradually die out and new organisms move in.

17. Ecological Succession Terms • Primary Succession • No exposed soil • Pioneer Species • The first species to populate a new area. • Tend to be small, fast growing and fast reproducing.

18. Ecological Succession (cont) • Each stage of succession alters the physical environment in ways that make it less favorable for their own survival but more favorable for the organisms that will replace them • Climax Community • A stable, mature community that marks the “end” of succession.

19. Ecological Succession (cont.) Secondary Succession -Occurs where an existing community has been cleared by a disturbance, natural or man-made, but the soil has been left intact.

20. Ecological Succession In this example, a volcanic eruption has destroyed the previous ecosystem.

21. Ecological Succession The first organisms to appear are lichens.

22. Ecological Succession Mosses soon appear, and grasses take root in the thin layer of soil.

23. Ecological Succession Eventually, tree seedlings and shrubs sprout among the plant community.