NOTES- Chapter 20 : Interactions of Life

I. Living Earth

A. __Biosphere______- the part of Earth that supports life.

1. The biosphere includes the top of the Earth’s _____crust______, all the __waters______on the

Earth’s surface, and the surrounding _____atmosphere______.

  1. ____Ecosystem_____ - All the organisms living in an area and the nonliving features in their

environment. (______biotic______= living factors ;_____abiotic_____ = nonliving factors)

1. _____Ecology_____ is the study of the interactions that occur among organisms and theirenvironment.

2. A _____population______is made up of all the organisms in an ecosystem that belong to the

same species. Ex. All the bison in a prairie ecosystem or coyotes in an area

3. A ______community______is all the populations in an ecosystem. Ex. Bison, grasshopper, cowbirds

C. ______Habitat______- the place in which an organism lives. (Ex. trees for woodpeckers etc.)

1. Must provide the kinds of ______food______, ____shelter______, _temperature___,

and __moisture_____ the organism needs to survive.

D. ______Niche______- the role of a species in an ecosystem.IT’S JOB

1. Includes the organisms ______food______, _____shelter_____, how it avoids __danger______,

finds _____a mate______, and ____cares for its young___.

2. All members of a species occupy ______The same Niche______.

II.Interactions Within Communities

A. Transfer of energy

1. ______Sun______- main source of energy for most life on earth

2. ______Autotrophs______(producers) - organisms that produce their own food

Most are _green_plants_or green algae____ that get energy through _photosynthesis__.

3.___Heterotrophs______(consumers) - organisms that cannot make their own

food but obtain energy by eating other organisms (get energy indirectly from the sun.)

a. __Herbivores______eat plants and are called __primary______

consumers(Ex.rabbit eating grass)

b. __Carnivores______eat animals. (ex. frog eats bug, lion eats

zebra)

  • those that eat herbivores are __secondary____ consumers.

(Ex. snake eating rabbit that ate the grass)

  • those that eat secondary consumers are __tertiary______consumers.

(Ex. hawk eating a snake that ate the rabbit that ate the grass)

c. _Omnivores______eat plants and animals. (Ex. us)

d. _Decomposers_____ consume dead plant and animal matter, so the nutrients

contained within them can be reused (break them down/rot)

(ex. earthworms, fungi, or bacteria)

****Each level (step) in the transfer of energy through an ecosystem is called a ___trophic level______.

(At each level _____less___ energy is made available (about ___90____ % lost at each level.)

4. ____Food Chain____ - a series of organisms that transfer energy through an

ecosystem.

  • All begin with a ______Producer______.

Plant ---- herbivore ---- carnivore ---- another carnivore ---- decomposer

(producer) (primary consumer) (secondary consumer) (tertiary consumer)

*ARROWS indicate _flow of energy______.

5. A network of food chains in an ecosystem make up a

______Food Web______.

( Most consumers eat more then one type of food)

*Changes in the population of one organism affect

All other populations in a community ______

______

Ex.If mouse population disappears then: populations that it ate would increase – plants, hawks would have less to eat, snakes would eat more grass hoppers, coyotes would eat more deer

6. * __Compost______- a pile of organic matter such as leaves, grass clippings, plant

clippings, newspapers, kitchen scraps, and soil etc. allowed to decay naturally.

Benefits:less stuff in landfills, good fertilizer, holds moisture, prevents disease

* ___Biomass______- the total mass of living and formerly-livingmaterial within a given area

*___Decay______- the breakdown of organic matter from larger to smaller molecules