Warm-Up (Use CUBE Test-Taking Strategies)
Monarch butterfly larvae eat milkweed, which is toxic to other insects. The toxin from the milkweed makes the butterflies poisonous to predators. Monarchs do not kill the milkweed plant when they eat from it. This relationship between the butterflies and milkweed is an example of which of the following?
a) Commensalism
b) Mutualism
c) Parasitism
d) Predation

SC.7.L.17.2 Symbiosis Essential Question:

SYMBIOTIC RELATIONSHIPS
Symbiosis is an between two different organisms that are in the same .
Types of symbiotic relationships:
o Commensalism: one organism benefits while the other is
o Parasitism: one organism benefits while the other is
o Mutualism: both organisms
Competition: When two or more organisms are trying to use the same at the same time.
Predation (Predator-Prey): When one organism and eats the other for and .
ENERGY TRANSFER IN FOOD WEBS
Producers: basis of the food web. light energy into food through . (makes own food)
Consumers: Get energy by other organisms. Herbivores, , or omnivores are all (eats others).
o Consumers eat plants and are herbivores.
o Consumers eat the primary consumers in a food web. ()
o Consumers eat secondary consumers. Considered a predator in the food web.
Decomposers: get energy by dead organisms.
LIMITING FACTORS
When there is not enough of one that many populations or individuals need. of resources creates and can lead to smaller populations due to organisms leaving the area or dying off.
Examples:
Not enough for organisms to live in. Not enough to live in or drink.
Not enough , causing crowding. Because organisms are closer, can spread easily.
becomes limited due to environmental or human impact.
There are fewer for organisms to keep their young safe.
Symbiosis, Food Webs, Limiting Factors We Do Identify the following examples as Mutualism (M), Commensalism (C), or Parasitism (P):
1. Barnacles live on a whale. Whales are unaffected.
2. Bees pollinate flowers and get nectar.
3. A tick burrows into your skin and sucks your blood.
4. A hermit crab uses another crab’s shell that they discarded.
5. Lichens are algae & fungi. The fungi holds the algae up closer to the Sun. The algae makes food for it & the fungi.
6. Polar bears usually live on ice sheets, however the ice has been melting. As a result, they move towards the land where grizzly bears live. What relationship exists between the polar and grizzly bears?
Refer to the Food Web below to answer the following questions:
7. What producers (autotrophs) are in this food web?
8. What kind of consumer would you classify the cricket as?
9. The alligator lizard and robin feed on the cricket. They are considered consumers.
10. The fox and cooper’s hawk would be consumers and considered predators in this food web.
11. What population would be most affected if the robins died off?

Identify which limiting factor is causing each scenario:
12. Humans interfere with turtle eggs at the beach.
13. Fish that travel in schools can sometimes get sick.
14. 100 lions compete to eat only 50 gazelles.
15. Lack of rain limits the plant growth in an area.
16. There are only 12 caves for 30 bears to hibernate in.
EXIT TICKET (Closing): What relationships can exist between organisms in ecosystems and how do organisms interact in order to survive?