1. "So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

2. Biotic-Biotic Community Relationships
SYMBIOSIS
COMPETITION
PREDATOR/PREY

3. Word root: Greek for “living together”
Symbiosis – when organisms of two species live closely together for a long time.
Word root: Greek for “living together”

4. Ex. badger and burrowing owl
3 Types of Symbiosis
Parasitism – one species benefits, the other is harmed. (+, - )
Ex. human and tapeworm
2) Commensalism – one species benefits, the other is not affected. ( +, 0 )
Ex. badger and burrowing owl
3) Mutualism – both species benefit ( +, + )
Ex. squirrel and oak

5. Practice with symbiosis What kind of symbiosis is shown in these examples? Parasitism (+,−) Mutualism (+, +) Commensalism (+,0)
The sphinx moth gets food from a honeysuckle flower. Pollen that sticks to the moth will pollinate the next flower.
2) Several small remora ride
a larger predatory shark
and may eat some of the
waste from the larger fish.

6. What kind of symbiosis is shown in these examples
What kind of symbiosis is shown in these examples? Parasitism (+,−) Mutualism (+, +) Commensalism (+,0)
3) The tick attaches itself to warm-blooded animals and uses the blood as a food supply. 4) Small mites feed on the body moisture of the long-horned beetle of South America. 5) Small scorpion-like animals sit on the long-horned beetle and eat mites.

7. What kind of symbiosis is shown in these examples
What kind of symbiosis is shown in these examples? Parasitism (+,−) Mutualism (+, +) Commensalism (+,0)
6) A plover is a bird that eats small parasites off the scales and teeth of a crocodile. 7) Many families own a dog. What kind of symbiosis is this?

8. Parasite-Related Vocabulary
host
vector
Example: Malaria is a disease that
infects humans that is transmitted by a mosquito bite. The mosquito is the vector and the human is the host.
The organism that has the parasite.
The organism that carries a parasite and spreads it to the host organism.

9. II. Competition
- when two organisms compete for the same resources in a community.
RESOURCES: what organisms need for survival and successful rearing of young.
examples: food, habitat, nesting sites or materials, mates, light, water

10. Types of competition
Interspecific – between members of two different species
Ex. Owls and foxes live in the same community and both eat rodents
2) Intraspecific – between members of the same species
Ex. All members compete for exact same food, habitat, etc.

11. III. Predator/prey relationships
One species has adaptations for hunting, the other for avoidance.
Some + for prey species:
When predators eliminate sick or old prey
controls over-population
controls spread of disease
less competition.

12. Biotic-biotic relationships drive evolution.
Predator and prey species co-evolve adaptations to best capture/escape each other.
Evolution also favors organisms with traits that make them best at competing for limited resources.
Example: Wolves that hunt best together as a pack are more likely to survive and pass on their traits.