Middle School Science Mrs. Figoten

In an ecosystem, anorganism’s role depends on:

How it obtains energy &

How it interacts with the other living things in the ecosystem

Organism’s energy role is:

ProducerConsumer Decomposer

ALL LIVING THINGS NEED ENERGY

Introducing

PRODUCERS

It all begins with plants that make their own food…..

Herbivores eat plants

Carnivores eat animals

Omnivores eat plants and animals

Scavengers eat dead animals

CONSUMERS CAN BE…

BACTERIA

FUNGI

SOME SOIL ORGANISMS

DECOMPOSERS ARE NATURE’S RECYCLERS

“3rd level consumer”

“1st level consumer”

“2nd levelconsumer”

consumer

Food chains show the flow of energy through consumer levels

known

CONIFEROUS FORESTFOOD WEB

ECOSYSTEMS DEPENDON THE BALANCE OF

THEIR FOOD WEBSThe loss of one organism may tip the delicate balance of survival for many other organisms within that food web

POPULATION SURVIVAL

Limiting Factors

Prevent population from increasing

Can happen if too many predators or not enough food -- changes in food web

Carrying Capacity

Largest population thatenvironment can support

Can happen from changes in food web

Population graph goes up & then flattens

“Carrying Capacity”of Ecosystem

(Most of one species ecosystem can hold)

Rabbit Growth Curve

0

5

10

15

20

25

30

0 2 4 6 8 10 12

Year

Po

pu

lati

on

Siz

e

Population

Population Graph goes up as species multiplies, then flattens

when there is no more food to continue reproducing.

Population of species can no longer grow.

Series of Predictable Changes

That Happen in aCommunity Over Time

Changes Over Time WhereNo Ecosystem Existed Before

New GrowthBegins with

Lichen & Mosses

Bushes &Small Treesafter 20-100 years

Grasses &Small Plantsafter 5-15 years

Mature Hardwood Trees after 150+ years

Lichen & Mosses first few years

Changes Over Time After a Disturbance Such as a Forest Fire in an Ecosystem

Mature Hardwood Trees after150+ years