Exam 45: The Global Ecosystem

By the end of 2012,atmospheric greenhouse gases had again reached new highs-the highest levels in 800,000 years.In the twentieth century,average world temperature rose by 0.7°C.If current trends continue,scientists expect that the average range of temperature increase by the year 2100 will be

How has the ability of humans to cooperate been reflected in the human response to climate change?

How do human activities such as deforestation and cattle grazing affect Earth's water cycle?

Which processes occurring in the ocean cycling of carbon are both physical,rather than biotic,processes?

About one-third of all the solar energy reaching Earth's surface is used in which process?

Based on our knowledge of the factors influencing primary productivity,the lowest level of net primary production would most likely be found in forests located in

What is the best and most complete description of the relationship between various biogeochemical cycles on Earth,as we currently understand these cycles?

Low levels of NPP around 30°N and 30°S latitude are associated with low levels of _______.

NPP in aquatic ecosystems is most often limited by

Nitrogen is often in short supply in terrestrial ecosystems because

What is the major reason scientists think declines in lizard populations around the world will lead to losses in community diversity?

With respect to matter,Earth is essentially a(n)_______ system,because the same matter cycles over and over through the system.

If global warming causes a mismatch between the time of a plant's flowering and the time of emergence of its major pollinator,this mismatch would be expected to affect all aspects of the plant-pollinator interaction except

In a biogeochemical cycle,a pool can remain balanced (that is,not increase or decrease in size)only if

Which statement most accurately represents the effect of human activities on Earth's climate?

If a huge solar flare causes an increase in the sun's surface temperature,the sun will emit wavelengths that are

What is the relationship between global warming and the greenhouse effect?

Of the following factors,which one leads to a decrease in heat absorption and therefore counteracts the effects of global warming?

If Hadley cells were to shrink rather than expand,rain near the equator would likely _______ and rain in the mid-latitudes would likely _______.

Is the amount of carbon entering and leaving the atmosphere over land balanced? If not,what is the difference and in which direction is the flux larger? Explain the reason for the difference.