Interactions In Ecosystems

1. Interactions In Ecosystems Chapter 14

2. Habitat and Niche • Habitat: Where an organism lives, including both biotic and abiotic factors (address) • Niche: How a species lives within its habitat (job)

3. Habitat and Niche • The organism’s niche is its role in an ecosystem—what food it eats, where its place is in a food web, how it competes for food, what temperatures it tolerates, what precipitation it can handle, the time of day it is active

4. Habitat and Niche • The organism’s habitat is where the niche conditions are found—where all of the biotic and abiotic factors are located for an organism to survive

5. Lion’s Niche • A lion uses the tall grasses of the African savanna as camouflage for hunting, uses gazelle which eat the grasses as food, hunts during low-light times like dawn or dusk, and spends afternoons in the shade to avoid the hot temperatures of the daylight hours

6. What if resourcesare limited? • If 2 species are competing for limited resources, the species that is better suited to the niche will outcompete, and the other will be forced into a different niche or become extinct in that habitat

7. Other alternatives to extinction • Niche partitioning: one squirrel might eat nuts from the top of the tree while the other could eat nuts on the ground • Evolutionary response: one type of squirrel could have squirrels with larger teeth survive more to crack larger nuts while smaller teeth would allow the other to eat small seeds instead

8. Community Interactions • COMPETITION: when two organisms fight for the same limited resource • Could be different species—grass, dandelions, and other plants compete for the same nutrients and water in a lawn • Could be the same species—birds in the spring during breeding season compete for mates and nesting sites

9. Community Interactions • PREDATION: when one organism captures and feeds on another • Snakes capturing and eating mice or other small rodents • Deer eating grass and leaves on trees

10. Community Interactions Predator: The consumer that hunts and consumes other organisms Snakes capturing and eating mice or other small rodents Prey: The organism that is hunted and consumed Mice and rodents that the snake eats

11. Predation

12. Symbiosis • Close ecological relationship between two or more organisms of different species that live in direct contact with each other • 3 types: • Mutualism • Commensalism • Parasitism

13. MUTUALISM • When BOTH organisms benefit from the interaction • Clownfish gets protection and a home • Anemone gets scrapes from fish and large fish the clownfish lures in

14. COMMENSALISM • When one receives a benefit and the other is not benefited or harmed • Barnacles living on whales get nutrients and whale is neither harmed nor benefited.

15. PARASITISM • When one receives a benefit and the other is harmed • Tomato hornworm covered with cocoons of wasp—they will digest the caterpillar by the time they metamorphose into adults