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ch 23 vocab test
ch 23 vocab
26
Science
6th Grade
03/12/2012

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Term
captive breeding
Definition
The mating of animals in zoos or wildlife preserves.
Term
poaching
Definition
Illegal killing or removal of wildlife from their habitats.
Term
biodiversity
Definition
The number of different species in an area.
Term
nonrenewable resource
Definition
A natural resource that is not replaced in a useful time frame.
Term
fishery
Definition
An area with a large population of valuable ocean organisms.
Term
aquaculture
Definition
The practice of raising fish and other water-dwelling organisms for food.
Term
renewable resource
Definition
A resource that is either always available or is naturally replaced in a relatively short time.
Term
keystone species
Definition
A species that influences the survival of many others in an ecosystem.
Term
extinction
Definition
The disappearance of all members of a species from Earth.
Term
What are the three main types of environmental issues?
Definition
Environmental issues fall into three general categories: resource use, population growth, and pollution.
Term
Why is population growth an environmental issue?
Definition
When a population grows, the demand for resources also grows.
Term
How might a growing population affect the supply of a renewable resource such as trees? Explain your answer.
Definition
Anything in the environment that is used by people is called a natural resource. Some natural resources are renewable. Renewable resources are either always available or are naturally replaced in a relatively short time. Renewable resources include sunlight, wind, fresh water, and trees. Some people think that renewable resources can never be used up. This is not always true. If people cut down trees faster than they can grow back, the supply of trees could run out.
Term
Why is weighing costs and benefits useful for decision makers?
Definition
Environmental decision making requires a balance between the needs of the environment and the needs of people. To help balance the different opinions on an environmental issue, decision makers weigh the costs and benefits of a proposal.
Term
Name one economic cost and one noneconomic cost of drilling for oil in Antarctica. List one benefit of drilling in Antarctica
Definition
Drilling for oil in Antarctica could provide a new source of energy. But an oil spill could harm the area’s penguins and other wildlife. Oil drilling would provide a new supply of oil for heat, electricity, and transportation.
Term
Suppose you were a world leader faced with the question of drilling in Antarctica. What decision would you make? Give reasons for your decision.
Definition
Oil drilling would provide a new supply of oil for heat, electricity, and transportation. If the worldwide supply of oil were larger, the price might drop, making oil available to more people. The plan would also create many new jobs. Would the benefits of drilling for oil in Antarctica outweigh the costs? This is the kind of question lawmakers must ask before they make environmental decisions.
Term
Why are forests considered renewable resources?
Definition
Because new trees can be planted to replace trees that are cut down, forests can be renewable resources.
Term
What are four ways fisheries can be managed for a sustainable yield?
Definition
Managing fisheries for a sustainable yield includes strategies such as setting fishing limits, changing fishing methods, developing aquaculture techniques, and finding new resources.
Term
What are two kinds of laws that regulate fishing? How can they help ensure the health of a fishery?
Definition
Laws can ban the fishing of certain species. Laws may also limit the number or size of fish that can be caught or require that fish be within a certain range of sizes. These laws ensure that young fish survive long enough to reproduce and that all of the largest adult fish aren’t caught. If a fishery has been severely overfished, however, the government may ban fishing completely until the populations recover.
Term
What might happen to a fish population over time if all the largest fish in the population were caught? Explain.
Definition
The fish were caught faster than they could breed, so the population decreased. This situation is known as overfishing.
Term
What are two ways in which biodiversity is valuable?
Definition
One reason is that wild organisms and ecosystems are a source of beauty and recreation. In addition, biodiversity has both economic value and ecological value within an ecosystem.
Term
What economic reasons could you give people in the rain forest for preserving the ecosystem?
Definition
Many plants, animals, and other organisms have economic value. They provide food and raw materials for medicines, clothing, and other products. For example, taxol, a cancer-fighting chemical, was first discovered in the Pacific yew tree. A country’s ecosystems can also be economically valuable. Wildlife tours in rain forests, savannas, mountains ranges, and other locations are common. This ecosystem tourism, or ecotourism, is an important source of jobs for such nations as Brazil, Costa Rica, and Kenya.
Term
What are three factors that affect the biodiversity in an ecosystem?
Definition
Factors that affect biodiversity in an ecosystem include area, climate, and diversity of niches.
Term
Would you expect to find great biodiversity in the tundra biome? Why or why not?
Definition
No. Not a lot of species of plants and animals to support life. Climate is also very cold and there isn't much rain.
Term
Name four human activities that can threaten biodiversity.
Definition
Habitat Destruction, Poaching, Pollution and Introducing exotic species into an ecosystem can threaten biodiversity.
Term
Black bears are roaming through a new housing development in search of food, even though the housing development is still surrounded by forest. How can you account for the bears’ behavior?
Definition
The houses were build in their habitat and now the bears are confused and have smaller area to find food.
Term
What are three approaches to protecting biodiversity?
Definition
Captive Breeding, Laws and Treaties, Habitat Preservation
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