Many scientists feel that we are headed toward another mass extinction because of man's actions and our effect on the ecosystem Earth. What have we learned from previous mass extinctions that may provide an idea of the consequences of such a mass extinction? What should man do to try to prevent such an occurrence?
What will be an ideal response?
The following ideas should be discussed: (1 ) After each mass extinction, there have been rapid bursts of speciation. (2 ) There is logic to the rates of extinction as well as probabilities of certain species surviving. (3 ) Genera that are widely distributed are more likely to survive than ones that are limited to small habitats are. (4 ) Extinct species do not simply come back and some of the changes may have devastating effects for a long time. The answer to the second question is open but thoughtful responses might include cessation of deforestation, reduction in greenhouse gas production, attempts to replenish the ozone layer, setting aside large amounts of land as nature reserves, genetic research, etc.
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Which of the following best describes the chemical equation for photosynthesis?
A. Carbon dioxide + Sugar + Energy = Oxygen + Water B. Water + Carbon dioxide + Energy = Sugar + Oxygen C. Oxygen + Sugar = Water + Carbon dioxide + Energy D. Oxygen + Water + Carbon dioxide = Sugar + Energy
Which of the following represents the largest contributor to the rate of oxygen exchange between the blood and the tissues?
1.the absolute partial pressure of oxygen in the blood 2.the difference in partial pressure of oxygen between the blood and the tissues 3.the absolute partial pressure of oxygen in the tissues 4.the partial pressure of carbon dioxide in the tissues
You just returned from a hiking/camping trip and are experiencing symptoms of an infection: high fever, swollen lymph nodes, and black-and-blue marks or hemorrhages under the skin. Your doctor asks if you have been in the four corners area of the U.S. (where the states of Arizona, Colorado, New Mexico, and Utah all meet). What does the doctor suspect?
A. Hemorrhagic fever is often associated with bats in that region of the U.S. B. Since there are many mosquitoes in that area, you might have been infected with Plasmodium. C. Those four states have high rates of Chikungunya, which is what the doctor suspects that you have. D. You might have picked up the plague bacterium from fleas that normally feed on rodents in that area.
Which of the following substances functions in the body's inflammatory response to prevent blood clots, regulate body temperature, and open airways to the lungs?
A) carotenoids B) leukotrienes C) prostaglandins D) melatonin