Human Impact on Earth

Global warming has been linked to a decrease in 

• the size of the polar ice caps 
• the temperature of Earth 
• the rate of species extinction 
• the rate of carbon dioxide production

Which human activity would preserve nonrenewable resources?

• deforestation
• removing carnivores from a forest 
• recycling
• heating homes with fossil fuels  

Continued depletion of the ozone layer will most likely result in

• an increase in skin cancer among humans 
• a decrease in atmospheric pollutants 
• an increase in marine ecosystem stability 
• a decrease in climatic changes

The acidity of a local stream would most likely be affected by

• a change in the percentage of decomposers living in the stream
• a new source of air pollution 
• a new predator species being introduced to the ecosystem
• a decrease in the amount of sunlight that reaches the stream

Increased industrialization will most likely

• decrease available habitats 
• increase environmental carrying capacity 
• increase the stability of ecosystems 
• decrease global warming

Which human activity is correctly paired with its likely future consequence?

• overfishing in the Atlantic — increase in supply of flounder and salmon as food for people 
• development of electric cars or hybrid vehicles — increased rate of global warming 
• use of fossil fuels — depletion of underground coal, oil, and natural gas supplies 
• genetically engineering animals — less food available to feed the world’s population

Which human activity would most likely deplete nonrenewable resources?

• use of natural enemies to eliminate insect pests
• development of wildlife refuges 
• governmental restriction of industrial pollution 
• increased use of fossil fuels

Deforestation of areas considered to be rich sources of genetic material could limit future agricultural and medical advances due to

• the maintenance of dynamic equilibrium 
• the loss of biodiversity 
• an increase in the ecosystem’s carrying capacity
• the depletion of the ozone layer

Deforestation by burning has been described as a "double whammy" to the environment, meaning it has 2 negative impacts. Why is this description accurate? 

• Forest burning releases CO₂ while decreasing oxygen, which disrupts cycles
• Deforestation reduces the amount of oxygen in the atmosphere, which depletes the ozone layer
• Forest clearing is often followed by land development, which often leads to increased noise pollution
• Deforestation increases the number of plant and animal species by destroying habitat

Approximately 75 percent of the Earth's surface is covered in water. So why is water considered such a precious resource?

• The greenhouse effect is causing most of the world's freshwater to be trapped in the atmosphere
• Only a small fraction of the Earth's water is freshwater available for drinking and irrigation
• Each year, more freshwater is being trapped in icecaps located at the North and South Poles
• Global warming caused by greenhouse gas emissions will likely cause Earth's oceans to evaporate