Download 4. symbiosis - Hicksville Public Schools

AIM: What are symbiotic relationships?
DN: Define a predator/prey relationship.
What determines the population size of
each?
Relationships could be either
1.Cooperative
2.competitive
Predator-Prey Relationship
Predator:
consumers that
actively hunt
other organisms
Prey:
the organism that
the predator eats
Predator and Prey population sizes
are closely linked
1. What happens if the predator
population increases? Why?
• The prey population will decrease.
• If there are more predators, they will need more
food to eat
2. What happens if the prey population
increases? Why?
• The predator population will increase.
• There will be more food available for the
predators.
3. What happens if the predator population
decreases? Why?
• The prey population will increase.
• There will be less predators to eat the prey.
4. What happens if the prey population
decreases? Why?
• The predator population will decrease.
• There will be less food for the predators to eat.
Symbiosis
• Any relationship where two species live closely
together.
• This relationship could benefit the species or it
could be detrimental to the species.
1. Parasitism:
2. Mutualism
3. commensalism
Parasitism
• One organism feeds on the tissues or body
fluids of another
• Host: the organisms on which a parasite feeds
• Parasite benefits, host is affected
Parasites Examples
• Fleas
• Ticks
• Malariaplasmodium
(protozoa)
• Tapeworm
• Hookworm
http://www.sporcle.com/games/tallsaul/plentiful-parasites
Mutualism
• Both species benefit
Nile Crocodile and Egyptian Plover
The plover eats the food
stuck in the crocodiles
mouth.
• Crocodile gets its teeth
cleaned
• Plover gets its nutrition
Digestive bacteria and humans
“good” bacteria exists in order to help us to
digest food.
– The bacteria stay alive.
– The human gets help with the process of
digestion.
Oxpeckers and zebras or rhinos
the oxpecker (a bird) lives on the
zebra or rhino, and eats all of the
bugs and parasites on the animal.
– The bird benefits by having a
readily available source of
food.
– The zebra or rhino benefits
from having the bugs removed.
– when there is a danger to the
zebra or the rhino, the
oxpecker flies high and makes
much noise in order to alert
nearby animals to the
impending danger (i.e. a
predator).
Commensalism
One species benefits and the other isn’t helped or
harmed
Remora Fish and Sharks
• “suckerfish- attaches itself to the
bodies of sharks, and uses the
shark for transportation as well
as protection from its predators.
• It also eats up the scraps of food
that are left over when the shark
eats its prey.
• The shark is not harmed nor
helped
Barnacles and Whales
• Barnacles do not
harm the whale
• Barnacles benefit
from moving
through the water
with the whale,
picking up food
1. How are predators different from parasites? What
doe these two groups have in common?
2. Describe the concept of mutualism. Give an
example.
3. Describe the concept of parasitism. Give an
example.
4. Describe the concept of commensalism. Give an
example.
5. Suppose an unusually severe winter killed most of
the snowshoe hare population in an area of
northern Canada. How would the lynx population
be affected?