Ch. 4 Lesson 2How do organisms

interact?

competition• when 2 or more species must

use same limited resources

behaviors that help animals avoid or reduce competition

1. hunting @ different times

behaviors that help animals avoid or reduce competition

2. living in groups– helps animals avoid predators

– work together to hunt for food

lichen• combination of fungi & algae

that live together

lichen• fungi get sugar,

nutrients & water from algae

• fungi shield algae from too much sunlight & warm temp.

Gold dust lichensGold dust lichens

parasite• organism that lives in or on

another organism

host• organism that is harmed by parasite

balsam woolly adelgid-parasite that

harms adult trees

parasite

What kinds of places do

lichens prefer most?

Lichen Location Color Distance from ground (cm)

Type of surface (tree, rock, etc.)

Environment (sunny or shady)

1.

2.

3.

4.

5.

Likin’ Lichens Hunt

Likin’ Lichens1. What kinds of surfaces do lichens grow on?

2. Do lichens seem to grow more in sunlight or shade?

3. Do lichens seem to grow more near the ground or away from the ground?

4. Do lichens seem to grow more in moist areas or dry areas?