Which of the following most directly explains the periodic fluctuations of the curve?
Seasonal variations in ocean water temperature
Daily variations in air temperature
Daily variations in sea level
Seasonal variations in photosynthetic activity
Which of the following is most likely a significant cause of the general trend indicated by the graph?
Increase in consumption of fossil fuels
Reduction of ozone concentrations in the upper atmosphere
Reduction in size of polar ice caps
Increase in evaporation of ocean water
Which environment is characterized by the highest diversity of tree species?
Which environment is most likely to be characterized by dry scrub with frequent fires?
Which environment is characterized by a short season of growth and reproduction?
Which of the following best helps to explain why phosphorus is often a limiting factor in many ecosystems?
Phosphate is not readily taken up by plants
Under many conditions, phosphorus forms stable insoluble compounds (rocks)
Phosphorus cycles very quickly through environments
There is usually a gaseous phase in the phosphorus cycle
Which of the following is a characteristic of tropical rain forests?
They rarely receive more than 100 cm of rain per year
Their soils are relatively poor in nutrients
Their soils typically have a high pH
They do not exhibit a great deal of species diversity
Boreal forests tend to have a thick layer of organic material but the soil is poor in nutrients. What is the BEST explanation for this?
The rapid growth rate of plants uses the nutrients rapidly
Low precipitation rates and cold temperatures slow decomposition
The soils have a low permeability and the nutrients do not dissolve in the soils
The organic material is low in nutrients
In August of 2014, residents of several Ohio cities that use Lake Erie as a drinking water source were warned not to drink tap water because of the presence of toxins released by blue-green algae (cyanobacteria). Which of the following is the most likely cause of recent blooms of blue-green algae in Lake Erie?
Increased recreational use of Lake Erie
Carbon in wastewater from fracking operations
Phosphorus contained in agricultural runoff
Cooler average summer temperatures
A forest has a gross primary productivity (GPP) of 3.8 kg C/m2/year and the rate of cellular respiration is 2.4 kg C/m2/year. What is the net primary productivity (NPP)?
1.0 kg C/m2/year
6.2 kg C/m2/year
1.4 kg C/m2/year
9.12 kg C/m2/year
Which of the following best explains why decomposers in soils and water are important to ecosystems?
They remove heavy metals
They store carbon dioxide
They recycle nutrients
They neutralize acid deposition
A field is abandoned, and an invasive plant that can live in nutrient-poor soil moves into the field. If the land is later cleared of this invasive species and it is discovered that the soil has an abundance of nitrogen compounds, what conclusion can best be made?
The plants were able to produce nitrogen in their leaves
Primary succession always produces and abundance of nitrogen
Bacteria in soil and in root nodules converted free nitrogen into nitrogen compounds
The plants used up all of the phosphorus and potassium and left the nitrogen behind
Which of the organisms illustrated above would be the TOP (apex) predator?
Giraffe
Vulture
Grass
Lion
Which of the organisms illustrated above would be the lowest trophic level?
Vulture
Grass
Giraffe
Lion
Which of the following is an example of a carbon sink?
Decomposition of food waste by bacteria
Combustion of fossil fuels in power plants
Clearing of trees in the Amazon forest
Deposition of organic matter on the deep ocean floor
Looking at Figure 3-3, what would be the MOST likely number of joules to fill in X, Y, and Z?
X=1; Y=500; Z=10,000
X=50; Y=50,000; Z=500,000
X=100; Y=1,000; Z=10,000
X=10,000; Y=500; Z=1
Approximately how much potential energy available from the sun’s rays hitting the Earth is used in photosynthesis?
10%
90%
1%
50%
Which group of organisms performs photosynthesis?
Autotrophs
Scavengers
Consumers
Heterotrophs
Which of the following is released by the process of photosynthesis?
Oxygen
Water
Carbon dioxide
Sunlight
Choose the correct sequence for energy flow within an ecosystem.