What is the Gaia hypothesis, and what does it say about the ...

[Frost2351]

What is the Gaia hypothesis, and what does it say about the importance of life on this planet?
 
  What will be an ideal response?

Question 2

Which of the three modern global change problems discussed in this chapter-- global warming, ozone depletion, or loss of biodiversity--do you consider to be the most serious?
 
  Give reasons for your answer. If you wish, include information drawn from other sources.
  What will be an ideal response?

[chinwesucks]

Answer to Question 1

The Gaia hypothesis states that Earth is a self-regulating system in which the biota plays an integral role. Also, this hypothesis suggests that the biota manipulate their environment for their own benefit or even, by optimizing the conditions for life, for the benefit of all living things.

Answer to Question 2

There are different opinions for this problem; one can argue that any one of them is the most significant problem. We have listed reasons students could use for all three of these problems below.

Students can argue that global warming is the most serious problem because:
 It affects the greatest number of people
 Migration of marine animals could result
 Rising sea level could result
 Cold climate species might die
 Ozone depletion and deforestation are currently both confined to particular areas whereas global warming is truly global

Students can argue that ozone depletion is the most serious problem because:
 It causes the most immediate damage to our planet and its inhabitants
 It can cause skin cancer
 It occurs faster than global warming, because global temperatures only rise a few degrees in 100 years , whereas severe ozone depletion occurred within less than decade over Antarctica.
 It could conceivably become global if stratospheric chlorine reached levels higher than those of today

Students can argue that loss of biodiversity is the most serious problem because:
 There is potential for recovery for the other problems: the ozone layer could recover within a few generations and greenhouse gas concentrations should return to normal within a few million years
 The recovery rate for species following extinction is tens of millions of years
 Once a species is gone, it is gone for good
 It could cause an imbalance in the Earth's ecosystem and economy
 Deforestation also contributes to global warming