Human Impact on the Environment

Global warming could cause the polar ice caps to melt increasing the amount of fresh water in the ocean and disrupting the flow of natural currents that cycle heat around the world. This change would most likely result in which of the following?

• An increase in climate change

• The collision of tectonic plates

• An increase in producer populations

• The reduction of ocean sediments

A toxin that breaks down slowly is introduced into the environment through the spraying of insecticides. The toxin is very lethal when an organism receives high levels of it. Which organism in the food web is in the most danger?

• Grass

• Rabbit

• Fox

• Fish

In the 1800s rabbits were introduced for the first time into Australia. Here they had no natural predators and a plentiful food supply. What happened several years after the rabbit was introduced into Australia?

• The rabbits began to overpopulate greatly.

• Populations of animals competing with rabbits grew.

• The rabbit population declined sharply.

• New rabbit predators evolved.

The primary cause of invasive species introduction is

• too much food

• human actions

• weather events

• asteroids

Several factors can lead to soil erosion. Which of these human activities is most likely to contribute to soil erosion?

• Clearing land for farming

• Planting trees and vegetation

• Preserving land as a wildlife habitat

• Reducing the amount of livestock in an area

Reforestation is the planting of trees that have been cut down by loggers and builders. One benefit of reforestation is restoring lost trees, which future generations can use for their wood. Which claim could be made about how reforestation could benefit a community?

• It limits the space available for building homes and business

• It decreases the chances of a forest fire spreading near people’s homes because of new tree growth

• It decreases the land available for growing crops and raising livestock

• It rebuilds forests, which provide shelter to animals, plants and other resources

The use of fertilizers on farmland can eventually cause an overgrowth of algae to appear in surrounding aquatic ecosystems. What process contributes to the eutrophication (excessive richness of nutrients) of these water sources and the increased growth of algae?

• A decreased use of water by animals

• An increase in runoff after heavy rains

• An increase in the sedimentation of rivers

• A decrease in the erosion of creek beds

Which of the following best describes the term biological magnification?

• The buildup of non-biodegradable chemicals in consumers as they are passed up the food chain

• When members of a crowded population are at odds for food, water, space, and other resources

• Using the earth's resources more carefully, and preserving and restoring natural habitats

• When food, water, and space are limited, causing carrying capacity to be reached

Which of the following is one way to preserve land resources?

• Reduce urban sprawl

• Clear cutting trees to increase land for farming

• Only build one park per city

• Only build recycling factories in the biggest cities

How do invasive plants damage the environment?

• Compete with native species
• Change plant community
• Alter diversity
• All of these