Ecology Review

Which factor would have the greatest effect on the flow of energy into an ecosystem?

• a large increase in the number of carnivores

• a small increase in the number of decomposers

• a small decrease in the amount of minerals available

• a large decrease 

  in the amount of 

  sunlight available

Dumping raw sewage into a river will lead to a reduction in dissolved oxygen in the water. What will this reduction most likely cause?

• an increase in fish populations

• a decrease in 

  most aquatic 

  animal 

  populations

• an increase in acid rain

• a decrease in water temperature

Which list includes only abiotic factors?

• soil, water, air, and sunlight

• ducks, fish, soil, and water

• humidity, temperature, rodents, and grasses

• trees, flowering plants, mosses, and ferns

Abiotic factors that affect the growth of grass in a lawn include

• bacteria and soil

• earthworms and nutrients

• moisture and 

  minerals

• fertilizer and decomposers

What are the abiotic factors that characterize a forest ecosystem?

• light and biodiversity

• temperature and amount of 

  available water

• types of procedures and decomposers

• pH and number of heterotrophs

An abiotic factor affecting the behavior and survival of such organisms as robins and violets is the

• population of rabbits

• length of daylight

• presence of harmful bacteria

• number of herbivores

A group of organisms within a given area capable of interbreeding and producing fertile offspring under natural conditions is called

• an ecosystem

• a community

• a food web

• a population

In order for an ecosystem to remain stable there must be

• drastic modifications to the environment

• interrelationships and 

  interdependencies among organisms

• limited biodiversity

• gradual changes in the climate

Male grizzly bears can maintain territorial control over many square miles. What is this role as a top predator in the territory known as?

• a biosphere

• an ecosystem

• a habitat

• a niche

The dodo bird inhabited the island of Mauritius in the Indian Ocean, where it lived undisturbed for years. It lost its ability to fly and it lived and nested on the ground where it ate fruits that had fallen from trees. There were no mammals living on the island. In 1505, the first humans set foot on Mauritius. The island quickly became a stopover for ships engaged in the spice trade. The dodo was a welcome source of fresh meat for the sailors and large numbers of dodos were killed for food. In time, pigs, monkeys, and rats brought to the island ate the dodo eggs in the ground nests. Which statement describes what most likely happened to the dodo bird within 100 years of the arrival of humans on Mauritius?

• Dodo birds developed the ability to fly in order to escape predation and their population increased.

• The dodo bird population increased after the birds learned to build their nests in trees.

• Human 

  exploitation and

   introduced 

  species 

  significantly reduced dodo bird populations.

• The dodo bird population became smaller because they preyed upon the introduced species.