The branch of biology dealing with interactions among organisms and between organisms and their environment


The simplest grouping of more than one kind of organism in the biosphere

Animal Training

Which of the following is NOT a basic method used by ecologists to study the living world


Which ecological inquiry method is an ecologist using when he or she enters an area periodically to count the population numbers of a certain species

Ecological Model

A mathematical formula designed to predict population fluctuations in a community could be

Chemosynthetic Bacteria

Which of the following organisms does NOT require sunlight to live

They both produce carbohydrates and oxygen.

In which way are plants in a sunny mountain meadow and sulfur bacteria in a deep-sea volcanic vent alike

more productive because bacteria living on the roots of legumes fix nitrogen in the soil.

Corn planted in a field that has been previously planted with legumes and then plowed under is likely to be


All the interconnected feeding relationships in an ecosystem make up a food


The total amount of living tissue within a given trophic level

Food Web

What is an ecological model of the relationships that form a network of complex feeding interactions among organisms in a community from producers to decomposers


What animals eat both producers and consumers

Trophic Level

What is the term for each step in the transfer of energy and matter within a food web

Carnivore, Consumer

A bird stalks, kills, and then eats an insect. Based on its behavior, which pair of ecological terms describes the bird


What goes in Box 5 of the food web in Figure 3-2

Energy, Biomass, and Numbers

What are the three kinds of ecological pyramids

Eliminated as heat

Only 10 percent of the energy stored in an organism can be passed on to the next trophic level. Of the remaining energy, some is used for the organism's life processes, and the rest


A word that means the same thing as consumer

Biological systems do not use up matter, they transform it

Matter can recycle through the biosphere


Which part of the water cycle is a biological process


Nitrogen fixation is carried out primarily by

Carry out essential life functions

Organisms need nutrients in order to

Energy flows in one direction, and nutrients recycle

The movements of energy and nutrients through living systems are different

Nutrients will be circulated throughout the biosphere

Biogeochemical cycling ensures that

An algal bloom occurs

What can happen after a lake receives a large input of a limiting nutrient


Animals that get energy by eating the carcasses of other animals that have been killed by predators or have died of natural causes

Plant life

Each of the following is an abiotic factor in the environment EXCEPT

Number and kinds of predators in the ecosystem

Which is a biotic factor that affects the size of a population in a specific ecosystem?

Tree roots split apart rocks in the ground

Which is an example of how biotic and abiotic factors interact

Grass, Grasshopper, Snake, Hawk

Which of the following is a food chain in the food web shown in Figure 3-4


An ecologist who is studying a group of ecosystems that have similar climates and are home to similar organisms is studying a


Ecologists can make using ecological models


Clouds are formed in the sky when water


Animals that feed on plants are

Food Chain

The passage of energy from one organism to another according to a particular feeding sequence


In an ecological pyramid, the biomass of living things at each higher level


Only about 10 percent of the in a trophic level is available to organisms at the next trophic level

Biogeochemical Cycles

Scientists classify the nitrogen, carbon, phosphorus, and water cycles

Healthy Ecosystem

A lake that is protected from receiving the excess runoff from a nearby farm is more likely to remain

Abiotic Factors

Seawater, sand on a beach, pebbles in the sand, and broken seashells are all examples of at a seashore

explain the relationship between sharks and the sun.

Sharks are the top consumer in a food chain that begins with algae. Algae are producers that get their energy from the sun. Energy from the sun eventually is passed on to the shark through the food chain that begins with the algae.

Compare and contrast photosynthetic producers with chemosynthetic producers

The two producers are alike because they both produce carbohydrates and oxygen and are essential to the flow of energy through the biosphere. They are different because they get their energy from different sources.

Why are decomposers the final consumers in every food chain?

In time, all living things die regardless of where they are in the food chain. The decomposers break down the remains of dead plants and animals, releasing substances that are reused by other organisms in the ecosystem

Consider a food web in which snakes eat mice; toads eat beetles; owls eat mice and toads; eagles eat rabbits, snakes, and owls; cougars eat deer; and foxes eat rabbits and mice. What animal occupies (gets energy in) more than one trophic level? Explain.

The eagle is a consumer at the third trophic level when it eats a rabbit and a consumer at the fourth trophic level when it eats a snake or an owl.

Why might a pyramid of numbers be turned upside down? Explain your answer with an example.

Sometimes consumers are much less massive than the organisms they feed upon. For example, thousands of insects may graze on a single tree. The tree has a lot of biomass, but it is only one organism. So the "base" of the pyramid will be small and the next level up will be wider.

Compare the movement of energy in the biosphere with the movement of matter through the biosphere.

Energy flows in one direction from the sun to producers and consumers. Matter moves in biogeochemical cycles through living systems, Earth, the atmosphere, and the oceans.

Explain how seepage and transpiration in Figure 3-5 are related.

Water seeps through soil and into the groundwater. Roots of trees and plants take the water up through their roots. Plants release the water through the process of transpiration. Both seepage and transpiration are parts of the water cycle.

Explain how the biogeochemical cycling of oxygen, carbon, nitrogen, and hydrogen are important to living systems.

The cycling of oxygen, carbon, nitrogen, and hydrogen make these materials available to living organisms in a form that cells can use.

What events typically contribute to an algal bloom in a lake or ocean?

A large input of a limiting nutrient, such as nitrogen or phosphorus, can cause the algae to grow and reproduce more quickly.

List three biotic and three abiotic factors that determine the survival of a rabbit in a temperate forest.

Biotic factors may include: plants the rabbit eats, predators that eat the rabbit, and animals that compete with the rabbit for food and territory. Abiotic factors may include: temperature, rainfall, and space.