1. Symbiosis: Living Together in an Ecosystem

2. Definitions
Population- A group of the same species living in the same area, potentially interacting with each other.
Community- A group of different species living in the same area, potentially interacting with each other.

3. Levels of Organization

4. Definitions
Symbiosis- A relationship between two organisms (can be temporary or permanent), usually one organism benefits or is harmed from the relationship.

5. Symbiosis
Symbiosis can affect distribution of organisms and increase or decrease fitness.
Effect on Species #1
Effect on Species #2

6. Mutualism – two species provide resources or services to each other, both are benefitted.
 enhances fitness of both species

7. Mutualism Example #1: Army Ant and Acacia Tree

8. Mutualism Example #2: Pistol Shrimp and Goby

9. Mutualism Example #3: Zebra and oxpecker

10. Here are three other examples of mutualistic relationships:
The bee and the flower- This benefits the plants. In this relationship, the bees get to eat, and the flowering plants get to reproduce.

11. Here are three other examples of mutualistic relationships:
The spider crab and the algae- The algae gets a good place to live, and the crab gets camouflage.

12. Here are three other examples of mutualistic relationships:
The bacteria and the human- The bacteria benefit by getting food, and the human benefits by being able to digest the food it eats.

13. Mutualism
Effect on Species #1
Effect on Species #2
Mutualism
(+,+)

14. 2) Commensalism – one species receives a benefit from another species
 enhances fitness of one species; no effect on fitness of the other species

15. Commensalism Example #1: Sharks and Remora

16. Commensalism Example #2: Clownfish and Anemone

17. Commensalism Example #2: Clownfish and Anemone

18. Other Commensalism Examples:
Cattle and Egrets- Cattle stir up insects as they eat grass. Egrets hang around and eat insects.

19. Other Commensalism Examples:
Barnacles and Whales- The barnacle benefits by filtering food as the whale swims. Its does not seem to affect the whale.

20. Commensalism Effect on Species #1 Effect on Species #2 Mutualism
Effect on Species #1
Effect on Species #2
Mutualism
(+,+)
Commensalism
(0,+)
Commensalism
(+,0)

21. 3) Predation – one species feeds on another
 Enhances fitness of predator but reduces fitness of prey
herbivory is a form of
predation

22. Predation Example #1: Bald Eagle and Fish

23. Predation Example #2: Bolas Spider

24. Predation Example #3: Orcas

25. Predation Example #4: Nile Crocodile

26. Predation Example #5: Great White Shark

27. Other Predation Examples:
Cattle and grass- Cows eat and kill the grass for food.

28. Other Predation Examples:
Baleen Whale and plankton- Whale filters plankton from water as it swims.

29. Other Predation Examples:
Wolf and Deer- Wolf kills and eats deer for food

30. Lynx and Snowshoe Hare-
As you can see by the graph, their populations are directly linked.

31. Predation Effect on Species #1 Effect on Species #2 Mutualism (+,+)
Effect on Species #1
Effect on Species #2
Mutualism
(+,+)
Predation
(-,+)
Commensalism
(0,+)
Commensalism
(+,0)

32. 4) Parasitism – one species feeds on another
 Enhances fitness of parasite but reduces fitness of host. It is in the parasite’s best interest not to kill the host.

33. Parasitism Example #1: Zombie Ants!!!

34. Parasitism Example #2: Bot Flies

35. Parasitism Example #3: Fleas, Mange, and Ticks

36. Other Parasitism Examples:
Fleas and Cats- fleas bite the Cats skin, sucking their blood, and causing them to itch and possible get sick. The fleas, in turn, get food and a warm home. Wasp eggs on back of caterpillar- Wasps lay eggs on the backs of caterpillars. When they hatch, the larvae eat the caterpillar. Mosquitos and humans- Mosquitos feed on the blood of animals. Sometimes they pass on other parasites (malaria is an example) to the host.

37. Parasitism Effect on Species #1 Effect on Species #2 Mutualism (+,+)
Effect on Species #1
Effect on Species #2
Mutualism
(+,+)
Predation
(-,+)
Commensalism
(0,+)
Parasitism
(+,-)
Commensalism
(+,0)

38. 5) Competition – two species share a limited resource
 reduces fitness of one or both species

39. Competition for Food

40. Competition for Mates

41. Competition for Territory

42. Other examples of competition:
Spruce and Pine Tree- They must compete for light, water and nutrients. Cheetahs and Lions- They must compete for the same prey such as gazelles. Coyotes and bobcats- They compete for the same prey such as rabbits.

43. Gray Squirrels and Red Squirrels- Until Americans introduced gray squirrels into parts of England in the early 20th century, red squirrels had been the only species of squirrel in the country. The gray squirrels were larger and bred faster and successfully competed for resources. Within a couple years of overlap in an area, the red squirrels disappeared.

44. Competition Effect on Species #1 Effect on Species #2 Mutualism (+,+)
Effect on Species #1
Effect on Species #2
Mutualism
(+,+)
Predation
(-,+)
Commensalism
(0,+)
Parasitism
(+,-)
Competition
(-,-)
Commensalism
(+,0)

45. 6) Amensalism is a relationship in which a product of one organism has a negative effect on another organism.
Penicillium and bacteria- penicillium secretes penicillin, a chemical that kills bacteria.
Black Walnut Tree and other plants- The Black Walnut gives off a chemical that harms or kills some species of neighboring plants.
Sheep and grass- Sheep make trails by trampling on thereby destroying a food source.

46. Amensalism Effect on Species #1 Effect on Species #2 Mutualism (+,+)
Effect on Species #1
Effect on Species #2
Mutualism
(+,+)
Predation
(-,+)
Commensalism
(0,+)
Parasitism
(+,-)
Competition
(-,-)
Amensalism
(0,-)
Amensalism
(-,0)
Commensalism
(+,0)

47. 7) Neutralism: describes the relationship between two species which interact but do not affect each other.
Neutralism describes interactions where the fitness of one species has absolutely no effect whatsoever on that of the other.
True neutralism is extremely unlikely or even impossible to prove.
When dealing with the complex networks of interactions presented by ecosystems, one cannot assert positively that there is absolutely no competition between or benefit to either species.
Since true neutralism is rare or nonexistent, its usage is often extended to situations where interactions are merely insignificant or negligible.

48. Neutralism Effect on Species #1 Effect on Species #2 Mutualism (+,+)
Effect on Species #1
Effect on Species #2
Mutualism
(+,+)
Predation
(-,+)
Commensalism
(0,+)
Parasitism
(+,-)
Competition
(-,-)
Amensalism
(0,-)
Amensalism
(-,0)
Neutralism
(0,0)
Commensalism
(+,0)