Ecology ch. 5 (22)

The extinction of species

• is a problem limited to the tropics.
• has been accelerated by the activities of people.
• is a problem only where topsoil and groundwater are limited.
• will not be a problem in the coming century.

Which of the following is a benefit of biodiversity to humans?

• timber
• food
• medicine
• all of the above

Chlorofluorocarbons (CFCs) in the atmosphere

• cause ozone to be broken down.
• change oxygen into ozone.
• convert sunlight into ozone.
• convert ozone into methane.

Ozone in the upper atmosphere

• leads to formation of acid precipitation.
• combines readily with water vapor.
• absorbs harmful radiation from the sun
• All of the above

Which of the following statements provides the best explanation for the disruption of ecosystems by pollutants?

• Pollutants differ chemically from naturally occurring substances.
• Only humans have uses for pollutant chemicals.
• Chemicals can undergo biological magnification and become highly concentrated in certain organisms.
• All pollutants are chemicals that can never be broken down, so they accumulate in ecosystems.

Scientists strongly suspect that temperatures are increasing on Earth because

• decomposers essential to recycling matter are being destroyed.
• too much oxygen is being given off by plants.
• increasing carbon dioxide in the atmosphere is trapping more heat.
• Earth is tilting further toward the sun in the summer.

Ecosystem disruption

• threatens the existence of thousands of species.
• increases biodiversity
• protects natural habitats.
• has no effect on biodiversity.

Which of the following processes is not primarily caused by humans?

• air pollution
• the greenhouse effect
• thinning of the ozone layer
• increased carbon dioxide levels

The field of study called conservation biology seeks to identify and maintain natural areas.

• true
• false

What strategy is used for conserving biodiversity in developing countries through visitors paying for guides, food, and lodging. 

• ecotourism
• conservation
• there is none