absolutely necessary or extremely important

An enclosed environment with a layer of dirt at the bottom in which plants and small animals can live

too many of the same organism in one area

type of organisms that normally live in a particular ecosystem

organisms that entered a new ecosystem and multiplied, hurting native species and their habitats

the way in which humans can help to take care of the environment

trees are cut down in large numbers to clear the land; this can lead to erosion and loss of soil

an effect or result

to change or modify

to disturb or cause damage

to grow and survive

Place where an organism lives, organisms' home

problem that occurs when grazing animals like cattle and sheep eat too much vegetation (grass)

An increase in the average temperature of the earth's atmosphere