1. How Organisms Interact in Communities
Predation

2. Coevolution – the process in which long term, interdependent changes take place in two species as a result of their interactions; some interactions among species are the result of a long evolutionary history in which many of the participants adjust to one another over time

3. Example: With its long beak, the humming bird is able to reach the nectar deep within the flower. This is an example of coevolution.

4. Interactions Between Populations:
predation – the act of one organism killing another for food
competition – when two or more organisms in the same community seek the same resource (e.g., food, water, nesting space, ground space)
symbiosis – the intimate living together of members of two or more species

5. Predation in Plants & Plant Defenses Against Herbivores:
thorns/spines/prickles
sticky hairs
tough leaves
secondary compounds – chemical defenses used by some plants

6. Symbiosis:
Two or more species living together in a close, long term association; some relationships can be beneficial to both organisms or benefit one organism and leave the other unharmed or unaffected.

7. Symbiotic Relationships:
mutualism – a symbiotic relationship in which both participating species benefit
ex: ants and aphids
commensalism – a symbiotic relationship in which one species benefits and the other is neither harmed or helped
ex: clown fish and sea anemone tentacles
parasitism – a symbiotic relationship between two species in which one benefits and the other is harmed
ex: dog and tick

8. Examples of Symbiotic Relationships

9. Use the symbols below to help you decide which symbiotic relationship is present:
(+,+) Mutualism - both benefit (+,0) Commensalism – one benefits, the other is neither harmed or helped (+,-) Parasitism – one benefits, the other is harmed

10. The drawing shows the Nile crocodile opening its mouth to permit the Egyptian plover (bird) to feed on any leeches attached to its gums.
crocodile/plover
Answer: + +
Mutualism

11. Heliconius butterflies scatter their eggs on young Passiflora plants
Heliconius butterflies scatter their eggs on young Passiflora plants. The developing larva may then eat the entire shoot.
butterfly/plant
Answer: _ +
Parasitism

12. Epiphytes are plants that live perched on sturdier plants
Epiphytes are plants that live perched on sturdier plants. They do not take any nourishment from their host and simply benefit from being better exposed to sunlight.
Epiphyte/other plant
Answer: + o
Commensalism

13. Clown fish are small reef fish that seek protection from predators by sheltering themselves among the stinging tentacles of sea anemones.
clown fish/ sea anemone
Answer: + o
Commensalism

14. Clown fish are small reef fish that seek protection from predators by sheltering themselves among the stinging tentacles of sea anemones. Clown fish are very territorial and can potentially scare off predators of sea anemones.
clown fish/sea anemone
Answer: + +
Mutualism

15. Aphids feed on plants which experience yellowing, stunting, mottling, browning, and curling of leaves. They may also inhibit its ability to produce crops.
aphids/plant
Answer: _ +
Parasitism

16. Phoresy, is a type of biological hitchhiking in which one organism receives access to transportation on the body of another animal, without the transporting animal being adversely affected by this arrangement.
hitchhiker/transporting animal
Answer: + o
Commensalism

17. The hermit crab is less likely to be eaten by cuttlefish when an anemone rides on its shell. The anemone gains access to a wider feeding range.
hermit crab/anemone
Answer: + +
Mutualism

18. Commensalism
Parasitism
Mutualism