This topic contains a solution. Click here to go to the answer

Author Question: What are some of the ways in which humans alter the natural vegetation? What will be an ideal ... (Read 67 times)

cartlidgeashley

  • Hero Member
  • *****
  • Posts: 572
What are some of the ways in which humans alter the natural vegetation?
 
  What will be an ideal response?

Question 2

How are humans affecting the phosphorus cycle?
 
  What will be an ideal response?



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

cuttiesgirl16

  • Sr. Member
  • ****
  • Posts: 345
Answer to Question 1

Answer: The health of vegetation is affected by climate, soils and human activities. Without humans, climate would have the strongest control on vegetation. Climate controls soil formation and plant growth so strongly that, with the exception of agricultural areas, world vegetation and soil patterns correspond closely to world climates. Humans, however, have had profound influences on ecosystems in most of the world's land areas, including the 37 percent of world land area (except Antarctica) that is cropland or permanent pasture.

By our actions, we are contributing to the continuous increase in the quantity of CO2 in the atmosphere. We are also changing the types of vegetation that grows in certain areas through our choice of crops to grow and types of practices we engage in, including monoculture, the application of chemical fertilizer and gene modification. Currently, about 8 percent of global photosynthesis takes place in agricultural lands.

By our consumption patterns, we are playing an even larger role in shaping the characteristics or fate of entire species and vegetation types. We do this in the decisions we make on what we consume either directly or indirectly by ourselves and our domestic animals.

Answer to Question 2

Answer: The major storage in the phosphorus cycle is in the lithosphere. It is released to soils by rock weathering, taken up by plants, and passed through the biosphere. Phosphorus is released back to soils and water by decomposition of waste and dead biomass. Phosphorus is an essential nutrient for plant growth.

When we harvest crops, the phosphorus they contain is removed from farm fields and this, along with removal in water that runs off the fields, depletes soil phosphorus stocks. We replace this lost phosphorus, and stimulate crop growth, by adding phosphorus fertilizers to the soil. These fertilizers are produced by mining phosphate-rich rock, and by mining accumulations of bird droppings in some coastal and island areas. The addition of large amounts of phosphorus (and other nutrients) to streams, lakes, and coastal areas, has dramatically altered aquatic ecosystems. These additions stimulate the growth of algae and can lead to lake and stream eutrophication and can lead to dead zones.

To combat these problems, farmers are encouraged to use less fertilizer, or to use techniques that maximize the efficiency of fertilizer use.





 

Did you know?

After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.

Did you know?

When Gabriel Fahrenheit invented the first mercury thermometer, he called "zero degrees" the lowest temperature he was able to attain with a mixture of ice and salt. For the upper point of his scale, he used 96°, which he measured as normal human body temperature (we know it to be 98.6° today because of more accurate thermometers).

Did you know?

More than 30% of American adults, and about 12% of children utilize health care approaches that were developed outside of conventional medicine.

Did you know?

For pediatric patients, intravenous fluids are the most commonly cited products involved in medication errors that are reported to the USP.

Did you know?

The oldest recorded age was 122. Madame Jeanne Calment was born in France in 1875 and died in 1997. She was a vegetarian and loved olive oil, port wine, and chocolate.

For a complete list of videos, visit our video library