1. Interactions Among Organismsp

2. Competition
relationship between organisms that strive for the same resources in the same place
resources might be food, water, or space
two different types of competition:
Intraspecific - between members of the same species
Interspecific – between members of different species

4. Symbiosis
a close relationship between two species in which at least one species benefits
for the other species, the relationship may be positive, negative, or neutral
Three types:
1. Mutualism
2. Commensalism
3. Parasitism

5. Mutualism: 2 organisms living together in such a way that both benefit.
Examples: clown fish & sea anemone
Nile crocodile & Egyptian plover

6. 2. Commensalism: 2 organisms living together in such a way as one benefits & the other is not affected. Examples: Hermit crabs, mites

7. 3. Parasitism: 2 organisms living together in such a way as one benefits (the parasite) & one is harmed (the host). Examples: Ascaris lumbricoides, ticks

8. Predation
Relationship between organisms in which one preys on the other
Prey have evolved defenses against predators
Horns, spit, quills, obnoxious odours, ink, poison, camouflage, armour, stingers, etc.
Predators evolved counter-defenses:
Strong digestive juices, poisons, camouflage, speed, good sense of smell/hearing/sight, antitoxins, etc.

9. Develop predator-prey cycles:
Prey becomes numerous
b/c more prey, predators grow & reproduce  more predators
b/c more predators, # prey deaths > # prey births & prey population drops
b/c prey #s drop, predators starve  predator population drops
b/c fewer predators, prey survive & reproduce  prey population grows
Cycle repeats

10. A C F D B E