Living Planet Episode 12- Study Questions

8. Describe the two types of solutions for human overpopulation. Compare benefits and drawbacks of each solution.

(1) decrease the number of births, or (2) increase the number of deaths. Option two is not a reasonable option for most people. After all, are you willing to kill off yourself and everyone you know just to control our population size? However, nature may use this option to solve the problem for us, whether we like it or not. Consider the Ebola virus or AIDS. These, or a new disease that we haven't heard of yet, could be the plague of the 21st century.

9. What is phosphorus used for in living organisms? by farmers?

- phosphorus is used by organisms to make nucleic acids (like DNA). It is also used to make phospholipids, which are a major component of the cell membrane of cells. The phosphorus cycle is different from either the nitrogen cycle of the carbon cycle because it does not have an atmospheric stage. The main form of phosphorus found in the environment is phosphate (PO4) - phosphates are found in soil, water and in sedimentary rocks. Growth of producers is limited by the availability of nitrogen and phosphorus. In nature, phosphorus is in short supply. The ingredients list on the label will tell you how much nitrogen and phosphate is in the fertilizer. - If you are a farmer, and you want good crops, you use lots of fertilizer. Some of the fertilizer is taken up by plants; some stays in the soil; some runs off when it rains and ends up in the water. The aquatic algae and plants now have LOTS of available nutrients and they grow and grow and grow. As there numbers increase, they use more and more oxygen at night. At some point, they use more oxygen than they produce. Then the ecosystem collapses. Everything that needs oxygen dies. And so, the results are : no more algae, no more producers, no more snails, no more fishes.

4. Describe the kinds of environmental degradation caused by increased human populations.

- resource overpopulation - habitat destruction - deforestation - polluting waters

1. The world population in 2016 was ____________________________ people.

7,339,034,137

2. The predicted world population in 2025 is ____________________________ people.

8 billion

3. The predicted world population in 2042 is ____________________________ people.

9 billion

10. Draw and describe the phosphorus cycle.

Here are the key steps of the phosphorus cycle -Over time, rain and weathering cause rocks to release phosphate ions and other minerals. This inorganic phosphate is then distributed in soils and water. -Plants take up inorganic phosphate from the soil. The plants may then be consumed by animals. Once in the plant or animal, the phosphate is incorporated into organic molecules such as DNA. When the plant or animal dies, it decays, and the organic phosphate is returned to the soil. -Within the soil, organic forms of phosphate can be made available to plants by bacteria that break down organic matter to inorganic forms of phosphorus. This process is known as mineralisation. -Phosphorus in soil can end up in waterways and eventually oceans. Once there, it can be incorporated into sediments over time.

6. Explain how energy consumption and solid waste production in the United States compares to our percent of the total world population.

In the United States, on average, each person uses many times the resources of a person in a developing country like Rwanda or Afghanistan. For example, the U.S. population makes up 4.4% of the world's population, but we use 20% of the world's energy and produce 25% of the world's solid wastes. And all these resources we use are ultimately extracted from or have effects upon natural ecosystems.

5. Define resource overpopulation.

Resource overpopulation is due to consumption of resources by each person. The effect one human being has on the environment depends on the amount of resources he or she uses.

7. Define carrying capacity. Explain how you would know when the carrying capacity of a population had been exceeded.

The carrying capacity of an ecosystem is the number of individuals it can support without sustaining damage. The question we face today is: Have humans outstripped the carrying capacity of the planet? How many humans can be supported without endangering the ecosystems on which all life depends? We have seen throughout this series, both in the video episodes and the study guide, the types of effects humans have on ecosystems: Global Warming, Ozone Depletion, Overfishing, Deforestation, Species Extinctions. Do you think that humans have yet to reach their carrying capacity? Or have we already surpassed it?

11. Explain how the use of phosphorus in fertilizers causes the phosphorus cycle to speed up.

guano which is a waste product produced (in this case) by guanay cormorants. Guano is also produced by bats. Large colonies of seabirds or bats produce large quantities of guano. Humans have used guano for fertilizers for thousands of years. In recent decades, however, the phosphate in fertilizer is made synthetically from phosphorus-containing rocks. Humans mine the rock, extract the phosphate, mix with nitrates and other nutrients and bag it up. As a result, the naturally slow cycling of phosphorus has been drastically accelerated.