4th Grade Science - Chapter 4 Changes in Ecosystems

They are healthy when their parts are in balance.

All living things are interrelated - what happens to one population affects the entire community.

Balanced ecosystems are constantly changing.

for example: when water evaporates from a pond, rain replaces the water.
This keeps the ecosystem in balance

All of the other living things population in the ecosystem will increase.

There are too many plant eating animals in the ecosystem.

There hasn't been enough rain to help the grass grow.

Other animals may have eaten many more of the grass eating animals.

When two or more species must use the same limited resources.

Living in groups

Hunting in the morning or evening.

Two different organisms live together to assist each other.

The organism in a relationship that is helped by the other.

The organism in a relationship that is harmed by the other.

The parasite may die because it does not have any food from the host.

Gradual Change from one community of organisms to another.

Usually occurs in stages.

Example: Bare land becomes grassland, grassland becomes shrubs, shrub land becomes forest land.

When a species dies out and is gone forever.

Changes in the earth's environment:
Climate changes
volcanoes
hurricanes
meteors,
habitat destruction
hunting

Populations of a species that have been reduced so much that they are in danger of becoming extinct.

YES

A forest fire - clears away dead plant matter and assists trees to creat a new forest by forcing sealed cones to release seeds.

Volcanic Ash - enriches the soil.

Floods - create more area for fish population to increase.