Science: Ecology and Biodiversity Worksheet

Question 1

Define biodiversity in your own words and name its three main levels.

Accepted Answer

Biodiversity is the variety of life in an area or on Earth as a whole. Its three main levels are genetic diversity, species diversity, and ecosystem diversity.

Question 2

Explain the difference between a habitat and a niche.

Accepted Answer

A habitat is the physical place where an organism lives. A niche is the role the organism plays in its ecosystem, including how it gets resources, interacts with other organisms, and survives in its environment.

Question 3

A food chain is grass -> rabbit -> fox. Identify the producer, the primary consumer, and the secondary consumer.

Accepted Answer

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

Question 4

Describe how energy flows through an ecosystem and explain why most food chains have only a few levels.

Accepted Answer

Energy flows from the Sun to producers and then to consumers and decomposers. Most food chains have only a few levels because a large amount of energy is lost as heat and through life processes at each transfer, so less energy is available for higher trophic levels.

Question 5

Compare mutualism, commensalism, and parasitism. Give one example of each.

Accepted Answer

Mutualism is a relationship in which both species benefit, such as bees pollinating flowers. Commensalism is a relationship in which one species benefits and the other is not significantly helped or harmed, such as barnacles living on a whale. Parasitism is a relationship in which one species benefits while the other is harmed, such as a tick feeding on a deer.

Question 6

What is an invasive species, and how can it affect biodiversity in an ecosystem?

Accepted Answer

An invasive species is a nonnative organism that spreads rapidly and causes harm in a new environment. It can reduce biodiversity by outcompeting native species, changing habitats, spreading disease, or disrupting food webs.

Question 7

A population of deer in a forest grows quickly for several years and then levels off. What is carrying capacity, and why might the population stop increasing?

Accepted Answer

Carrying capacity is the largest population size that an environment can support over time. The population might stop increasing because resources such as food, water, space, or shelter become limited, or because disease and predation increase.

Question 8

Explain the difference between density-dependent and density-independent limiting factors. Give one example of each.

Accepted Answer

Density-dependent limiting factors have a stronger effect when a population becomes crowded, such as disease spreading more easily in a dense population. Density-independent limiting factors affect populations regardless of density, such as a drought, wildfire, or hurricane.

Question 9

Why are decomposers important in ecosystems?

Accepted Answer

Decomposers are important because they break down dead organisms and wastes, returning nutrients to the soil and water. This recycling supports producers and helps keep matter moving through the ecosystem.

Question 10

Describe one way that high genetic diversity can help a population survive environmental change.

Accepted Answer

High genetic diversity increases the chance that some individuals in a population have traits that help them survive new conditions, such as disease, temperature change, or reduced water availability. Those individuals are more likely to reproduce and help the population continue.

Question 11

A biologist finds that a wetland with many plant, insect, bird, and fish species recovers quickly after a storm. Explain how biodiversity can increase ecosystem stability.

Accepted Answer

Biodiversity can increase ecosystem stability because many species may perform similar ecological roles. If one species declines after a disturbance, others can still help maintain food webs, nutrient cycling, and other ecosystem processes, allowing the ecosystem to recover more quickly.

Question 12

What is the difference between primary succession and secondary succession?

Accepted Answer

Primary succession begins in an area where no soil exists, such as on bare rock after lava cools or glaciers retreat. Secondary succession begins where soil is already present after a disturbance, such as after a fire, flood, or abandoned farm field.

Question 13

Explain how human activities such as deforestation or pollution can reduce biodiversity.

Accepted Answer

Human activities such as deforestation and pollution can reduce biodiversity by destroying habitats, fragmenting ecosystems, introducing toxins, and changing environmental conditions faster than many species can adapt. These changes can cause population declines and extinctions.

Question 14

A scientist is studying wolves, elk, grasses, and streams in one region. Why is this an example of studying an ecosystem instead of just a population?

Accepted Answer

This is an example of studying an ecosystem because it includes multiple species and nonliving parts of the environment, such as streams. A population study would focus on only one species living in the same area.

Question 15

Choose one conservation strategy, such as habitat restoration, wildlife corridors, captive breeding, or protected areas, and explain how it can help preserve biodiversity.

Accepted Answer

One conservation strategy is habitat restoration. It can help preserve biodiversity by rebuilding damaged ecosystems so that native species have access to food, shelter, breeding sites, and other resources needed for survival and reproduction.

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Science: Ecology and Biodiversity

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