Chapter 18 Notes 

I.                 Everything is Connected

A. Studying the Web of Life

Ecology-study of interactions between organisms with each other and nonliving environment

1.  The Two Parts of an Environment

Biotic-living(ex. Grass, animals, bacteria

Abiotic-nonliving(ex. Sun, air, water, rock)



2. Organization in the Environment



3. Populations

Organisms of same species living together (ex. deer on Green Mt.)


4. Communities

All living things(plants & animals) that live & interact in an area (ex. all plants and animals on Green Mt.)


5. Ecosystems

Living and nonliving together in an area (ex. all organisms and rocks, water, soil on Green Mt.)



6. The Biosphere

Air, water, earth where life exists


II Living Things Need Energy

A.           The Energy Connection



Make their own food by photosynthesis-have chlorophyll







Herbivore-eats plants

Carnivore- eats animals


Omnivore-eats plants and animals

Scavengers-omnivores that eat dead plants & animals


3.Decomposers-break down dead organisms(bacteria & fungi)



 4.Food Chains and Food Webs

Chain-shows how energy flows from 1 to another

Web-shows how energy in food is in relationship in an ecosystem

Energy flows from sun->plants-> animals




5.Energy Pyramids

Shows ecosystem’s loss of energy as moves up.  Much energy at base-less as move up

B.            Wolves and the Energy Pyramid

1.Gray Wolves and the Food Web

Wolves eliminated/disturbed food  web/ elk starved

Wolves reintroduced into Yellowstone Park

2.Balance in Ecosystems

If all alpha predators removed (ex. wolves, mt. lions, bears), balance of nature upset


III Types of Interactions

A.           Interactions with the Environment

1.Limiting Factors- anything that is scarce enough to limit size of population(ex. water, food, habitat)

2.Carrying Capacity-largest population an area can support (enough food, water, habitat for all)


B.             Interactions Between Organisms-4 ways to interact

C.            Competition-2 or more try to use the same resource

D.          Predators and Prey

1.Predator Adaptations

Predator-one who eats

Prey- one eaten

2.Prey Adaptations-may stay together, reproduce in great numbers, have warning coloration

3.Camouflage-blend in


4.Defensive Chemicals-skunk

5.Warning Coloration-bright colors

E. Symbiosis-long term relationship between species

1.Mutualism-both benefit


2.Commensalism-one benefits, other not helped/harmed


3.Parasitism-one benefits/one harmed


F. Coevolution-2 species change over time together

1.Coevolution and Flowers

Pollinator-organism that carries pollen from 1 flower to another(bats, insects)



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