Environmental Science: Biodiversity Worksheet

Question 1

Define biodiversity and identify its three major levels.

Accepted Answer

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

Question 2

A forest contains 12 species of trees, 35 species of insects, 8 species of mammals, and 20 species of birds. What is the species richness of the forest based on these groups? Explain what species richness measures.

Accepted Answer

The species richness is 75 species because 12 + 35 + 8 + 20 = 75. Species richness measures the number of different species present in a community or ecosystem.

Question 3

Two grasslands each contain 10 plant species. In Grassland A, all 10 species have similar numbers of individuals. In Grassland B, one species makes up 90 percent of all plants. Which grassland has greater species evenness, and why?

Accepted Answer

Grassland A has greater species evenness because the individuals are distributed more equally among the 10 species. Grassland B is less even because one species dominates the community.

Question 4

Explain how high genetic diversity can help a population survive an environmental change, such as a new disease or drought.

Accepted Answer

High genetic diversity increases the chance that some individuals have traits that help them survive the new disease or drought. Those survivors can reproduce and pass helpful traits to the next generation.

Question 5

A population of 200 frogs lives in a wetland. A road is built through the wetland, dividing the population into two smaller groups that rarely interbreed. Describe one possible effect of this habitat fragmentation on the frogs' genetic diversity.

Accepted Answer

Habitat fragmentation can reduce gene flow between the two frog groups. Over time, each smaller group may lose genetic diversity through inbreeding or random changes, making the population less able to adapt.

Question 6

List three ecosystem services that biodiversity can support, and briefly describe one of them.

Accepted Answer

Biodiversity can support pollination, water purification, soil formation, climate regulation, pest control, and food production. For example, pollinators such as bees help many flowering plants reproduce, including crops humans eat.

Question 7

A farmer grows only one crop variety across a large field. Explain why this monoculture may be more vulnerable to pests or disease than a diverse farm system.

Accepted Answer

A monoculture may be more vulnerable because many plants have similar genetics and the same weaknesses. If a pest or disease can attack that crop variety, it can spread quickly through the entire field.

Question 8

Use the data table: Site A has 4 species with counts 25, 25, 25, and 25. Site B has 4 species with counts 70, 10, 10, and 10. Both sites have the same species richness. Which site has higher biodiversity overall, and why?

Accepted Answer

Site A has higher biodiversity overall because it has the same species richness as Site B but much higher evenness. The individuals are evenly distributed among species in Site A, while Site B is dominated by one species.

Question 9

Describe how an invasive species can reduce biodiversity in a local ecosystem.

Accepted Answer

An invasive species can reduce biodiversity by outcompeting native species for food, space, light, or other resources. It may also prey on native species or introduce diseases, causing native populations to decline.

Question 10

Coral reefs support many species but are threatened by warming oceans and pollution. Explain why the loss of coral reefs would affect more than just coral species.

Accepted Answer

The loss of coral reefs would affect many organisms because reefs provide habitat, food sources, and breeding areas for fish, invertebrates, and other marine life. When coral declines, the entire reef community can become less diverse and less stable.

Question 11

A conservation group wants to protect a rare plant species. The plant grows only in one valley and has low genetic diversity. Give two reasons this species may be at high risk of extinction.

Accepted Answer

This species may be at high risk because it has a very limited range, so one fire, flood, or development project could destroy much of its habitat. Its low genetic diversity also makes it less likely to adapt to disease or environmental change.

Question 12

Explain the difference between in situ conservation and ex situ conservation. Give one example of each.

Accepted Answer

In situ conservation protects species in their natural habitats, such as creating a wildlife reserve. Ex situ conservation protects species outside their natural habitats, such as storing seeds in a seed bank or breeding endangered animals in a zoo.

Question 13

A map shows that a proposed wildlife corridor would connect two protected forest areas. Explain how this corridor could help maintain biodiversity.

Accepted Answer

A wildlife corridor could help maintain biodiversity by allowing animals to move between protected areas. This movement can increase access to food and mates, reduce isolation, and support gene flow between populations.

Question 14

Climate change can shift temperature and rainfall patterns. Describe one way this can affect species distributions and one way it can affect ecosystem interactions.

Accepted Answer

Climate change can cause species to move toward cooler areas, higher elevations, or different habitats as conditions shift. It can also disrupt ecosystem interactions, such as when flowers bloom before their pollinators are active.

Question 15

You are comparing two conservation plans. Plan 1 protects a small area with one endangered species. Plan 2 protects a larger habitat that contains many native species, including pollinators, predators, and plants. Explain why Plan 2 might provide broader biodiversity benefits, while still recognizing why Plan 1 could be important.

Accepted Answer

Plan 2 might provide broader biodiversity benefits because it protects a larger ecosystem and many interacting species, which can support food webs and ecosystem services. Plan 1 could still be important if the endangered species is highly threatened, unique, or found nowhere else.

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Environmental Science: Biodiversity

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