1. Aim #40: How do organisms interact in the environment?
Think Questions:
1) The organisms in a pond and the physical factors influencing them best describe
a population b. an ecosystem c. a biosphere d. a food chain
2) An earthworm lives and reproduces in the soil. It aerates the soil and adds organic material to it. The earthworm is a source of food for other organisms. All of these statements together best describe
a. a habitat b. autotrophic nutrition c. an ecological niche d. competition

2. I. Interactions in the Environment A. Symbiosis – living together
1. Mutualism - both species benefit from an interaction
+ / +
2. Commensalism – one species benefits, the other isn’t harmed or benefited + / 0
*Q: We’re not really sure if commensalism exists in the wild. Why do you think there is doubt?
I know we talk a lot about competition – but it’s not like organisms are just battling it out all day! I lot of organisms actually survive because of other organisms. Interactions can be good, bad, or neutral.
There’s 3 kinds of symbiosis
Example of mutualism: the clownfish feeds on small invertebrates which otherwise potentially could harm the sea anemone, and the fecal matter from the clownfish provides nutrients to the sea anemone. The clownfish is also protected from predators by the anemone's stinging cells, which the clownfish is immune to.
Spider webs growing on plants may be a commensal symbiosis, but it probably does harm or help the plant in some way or another.

3. *Q: Why aren’t there any - / - relationships?
3. Parasitism – one organisms benefits (parasite), the other organism is harmed (host) / -
*Q: What benefit does the cuckoo bird get? What harm does the white-egg bird get?
Parasites have evolved in such a way that they harm, but usually do not kill the host species. If the host were to die, the parasite would also die unless it can quickly find another host.
In some forms of parasitism, an animal will lay their eggs in a different animal’s nest, then fly away. They get to reproduce, but don’t have to do any of the work!
*Q: Why aren’t there any - / - relationships?

4. *Q: What is the relationship between autotrophs and heterotrophs?
B. Food Relationships
1. Organisms that make their own food are called __________.
autotrophs
a. These are also called _________.
producers
2. Organisms that get their food from other sources are called ____________.
heterotrophs
a. These are also called __________.
consumers
*Q: What is the relationship between autotrophs and heterotrophs?
Heterotrophs rely on autotrophs for food!
(Start writing the chain of food relationships on the board as a running chart)

5. eat plants eat meat eat plants and meat b. 5 kinds of heterotrophs:
Herbivore =
Carnivore =
Omnivore =
Detritivore =
Decomposer =
eat plants
eat meat
eat plants and meat
eats things that are dead (but they don’t kill it themselves)
eats dead things and breaks them down
Decomposers release the nutrients from the dead things that they eat. This can be leaves, animals, bacteria… A great example of this is fungi. Some protozoans and bacteria also do this.
- Herbivores are not JUST food for carnivores! They have defenses! Let’s see!

6. i. We can then divide heterotrophs into 3 behavioral patterns:
Predators – ??
Prey – ??
Scavengers – ??

7. Draw a food web using the following terms:
Exit Slip
Draw a food web using the following terms:
Autotroph
Herbivore
Carnivore
Omnivore
Detritivore
Decomposer
Remember: The arrow points to the thing that is doing the eating! (The arrow points to where the energy is going!)