The total amount of energy invested in the production of living biomass in a community is that community's
Select one:
a. gross primary productivity
b. net primary productivity
c. gross photosynthetic efficiency
d. net photosynthetic efficiency
Which of the following factors accounts for the largest number of documented extinctions that have occurred in the last 1,000 years?
Select one:
a. Deforestation
b. Habitat fragmentation
c. Pollution
d. Invasive species
In terrestrial ecosystems, the greatest current cause of species endangerment is
Select one:
a. invasive species
b. habitat loss
c. overharvesting
d. pollution
Carbon dioxide has a warming effect on the earth's atmosphere. This is because it absorbs
Select one:
a. ultraviolet radiation coming from the earth's surface
b. visible light coming directly from the sun
c. ultaviolet radiation coming from the sun
d. infrared radiation coming from the earth's surface
The overall productivity of the open ocean has declined as a result of global warming.This is believed to be because
Select one:
a. ocean stratification has intensified
b. cloud cover has increased, reducing sunlight over the ocean
c. higher temperatures have directly inhibited algal photosynthesis
d. the amount of carbon dioxide dissolved in the ocean has decreased
Positive feedback might occur in response to increasing atmospheric carbon dioxide levels as a result of
Select one:
a. soil decomposers increasing the rate at which they break down organic molecules
b. oceans absorbing more carbon dioxide in the form of bicarbonate ions
c. an increase in the rate at which fossil fuels are formed
d. plants accelerating their growth by taking up more carbon dioxide
Which nitrogen-containing molecules in soil represent a usable source of nitrogen for plants?
Select one:
a. Nitrogenous bases of nucleic acids
b. All of these
c. Ammonium
d. Amino acids
In a tropical forest ecosystem, "edgeΓ’ΒΒ habitat is considered to be of relatively low quality for conservation purposes because it
Select one:
a. tends to contain more invasive species
b. all of these
c. tends to contain more early-successional species
d. is more exposed to the effects of wind
