Biology: Ecology Worksheet

Question 1

Define ecology in your own words. Include both living and nonliving parts of the environment in your definition.

Accepted Answer

Ecology is the study of how living things interact with each other and with nonliving parts of their environment, such as water, sunlight, air, soil, and temperature.

Question 2

A pond contains frogs, algae, fish, insects, rocks, water, sunlight, and bacteria. List three biotic factors and three abiotic factors from this pond ecosystem.

Accepted Answer

Three biotic factors are frogs, algae, and fish. Three abiotic factors are rocks, water, and sunlight. Biotic factors are living or once-living parts, while abiotic factors are nonliving parts.

Question 3

In a forest food chain, grass is eaten by a rabbit, and the rabbit is eaten by a fox. Identify the producer, the primary consumer, and the secondary consumer.

Accepted Answer

The grass is the producer because it makes its own food using sunlight. The rabbit is the primary consumer because it eats the producer. The fox is the secondary consumer because it eats the rabbit.

Question 4

Draw or describe a food chain with at least four organisms. Label each organism as a producer, primary consumer, secondary consumer, or tertiary consumer.

Accepted Answer

One possible food chain is grass to grasshopper to frog to snake. The grass is the producer, the grasshopper is the primary consumer, the frog is the secondary consumer, and the snake is the tertiary consumer.

Question 5

Energy decreases as it moves up an energy pyramid. If producers in an ecosystem have 10,000 units of energy, about how many units are usually available to the primary consumers using the 10 percent rule?

Accepted Answer

About 1,000 units of energy are available to the primary consumers. This is because 10 percent of 10,000 is 1,000.

Question 6

A population of deer in a forest grows quickly for several years, then stops growing because food and space become limited. What ecological idea explains why the population stops increasing?

Accepted Answer

The population stops increasing because it has reached the carrying capacity of the environment. Carrying capacity is the largest population size that an ecosystem can support with its available resources.

Question 7

Explain the difference between a habitat and a niche. Use one animal as an example.

Accepted Answer

A habitat is the place where an organism lives, while a niche is the organism's role in the ecosystem. For example, a frog's habitat may be a pond, and its niche includes eating insects, being prey for snakes, and using water and plants for shelter.

Question 8

In a meadow, bees collect nectar from flowers and help move pollen between flowers. What type of relationship is this, and why?

Accepted Answer

This is mutualism because both organisms benefit. The bee gets food from the nectar, and the flower gets help with pollination.

Question 9

A tick attaches to a deer and feeds on its blood. The tick benefits, and the deer is harmed. What type of symbiotic relationship is this? Explain your answer.

Accepted Answer

This relationship is parasitism because the tick benefits by getting food, while the deer is harmed by losing blood and possibly being exposed to disease.

Question 10

Owls and hawks both hunt mice in the same field. Explain how competition could affect these predators if the mouse population decreases.

Accepted Answer

If the mouse population decreases, owls and hawks may compete more strongly for the remaining mice. Some predators may have less food, which can lead to lower survival, movement to new areas, or smaller populations.

Question 11

A certain cactus has thick stems that store water and sharp spines that protect it from animals. Explain how these traits help the cactus survive in a desert ecosystem.

Accepted Answer

The thick stems help the cactus store water during dry conditions. The sharp spines protect the cactus from animals that might eat it, so both traits are adaptations that help it survive in the desert.

Question 12

After a forest fire, grasses and small plants begin growing in the burned area. Over time, shrubs and young trees appear. What process is happening? Explain your answer.

Accepted Answer

Secondary succession is happening. This process occurs when an ecosystem recovers after a disturbance, such as a fire, while soil is still present.

Question 13

A river receives extra fertilizer runoff from nearby farms. Algae begin to grow very quickly, and later many fish die. Explain one reason fertilizer runoff can harm aquatic ecosystems.

Accepted Answer

Fertilizer runoff can cause algal blooms. When algae die and decompose, bacteria use up oxygen in the water, which can leave too little oxygen for fish and other aquatic animals to survive.

Question 14

A food web includes grass, rabbits, mice, snakes, hawks, and decomposers. If the snake population suddenly decreases, predict one possible effect on another population in the food web.

Accepted Answer

If the snake population decreases, the mouse or rabbit population may increase because fewer snakes are eating them. The hawk population might also be affected if hawks depend on snakes or compete for similar prey.

Question 15

Choose one human activity that can reduce biodiversity in an ecosystem. Describe the activity and explain how people could reduce its impact.

Accepted Answer

One activity that can reduce biodiversity is habitat destruction, such as clearing forests for buildings or roads. People could reduce its impact by protecting natural areas, planting native species, creating wildlife corridors, and using land more carefully.

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Biology: Ecology

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