Human Impact on Ecological Change - AP Environmental Science

Many Rocky Mountain and Western conifer species are adapted to germinate only after being exposed to temperatures typical of a wildfire. Pioneer species and shrubs typically have no problem generating after a clear-cut, but often foresters have to plant pine saplings in a clear-cut area, because remaining seeds will not germinate.

Although human activites are reducing the extent of many biomes, they are causing the spread of deserts, a process called desertification. Rain forests are being felled for lumber or burned down for ranching or agriculture. Africa's rapidly expanding human population threatens the wildlife of the savanna. The tallgrass prairie has been converted to agricutural land. Clearing for lumber, agriculture, and housing has dramatically reduced America's deciduous forests.

Composting is a process in which purely organic waste is converted into a rich soil conditioner commonly known as 'compost'. The process usually begins with household food and plant scraps, which are broken down over time and added to soil to fertilize the soil and help it retain moisture.

"Habitat connectivity" is the only term that describes something positive that increases the quality of biodiversity. It is defined as the degree to which landscape facilitates movement and ecological flows important for the survival of other species. Every other term describes things that decrease habitat and negatively impact biodiversity.

The correct response is "eutrophication." It is the only term that is specific to aquatic systems and the input of excess nutrients by way of pollution. The terms "bioaccumulation" and "biomagnification" describe how substances such as toxins accumulate within organisms and trophic levels—not an aquatic ecosystem. Last, "fragmentation" has nothing to do with the question because it refers to when habitats are parceled apart due to human activities.

The correct response is “heterogeneous landscapes.” This is the only answer choice that describes landscapes with different types of habitats. Different types of habitat are necessary to maintain biodiversity. "Uniform" and "Homogeneous" describe landscapes that are very similar. "Artificial Landscape" does not arise from a natural process.

Environmental science integrates information from several fields. These fields include the natural and physical sciences such as biology, chemistry, and geology; but social science and humanity fields are important to the study of the environment. These fields include political science, economics, and ethics. Environmental science studies organisms, including humans, and their environment as well as their affect on the environment.