Spheres & Cycles
What process is common among the nitrogen, phosphorus, and carbon cycles?
Assimilation
What are two reasons animals might migrate?
To find food, reproduce, or reach a more suitable climate
Where does all of the energy in an ecosystem originate?
The sun
What are the signs for competition and why?
(-,-) because both are being harmed by a lack of resources
Which Earth sphere includes glaciers, ice sheets, and sea ice?
Cryosphere
Why is denitrification important to the nitrogen cycle
It returns nitrogen gas to the atmosphere
Which aquatic biome forms where freshwater mixes with saltwater?
Estuary
Why is it rare for an ecosystem to have 5 or even 6 trophic levels?
Because significant energy is lost at each level
A predator population increases. Predict one likely effect on prey and one possible effect on producers.
Prey decrease; producers may increase due to lack of prey
A person moves to a high-altitude city and, after several weeks, produces more red blood cells. Is this an adaptation or acclimation? Explain.
Acclimation, because it is a change within an individual’s lifetime in response to environmental conditions.
A volcanic eruption releases ash and gases into the atmosphere. Describe one way this change in the atmosphere could cause a change in the other three spheres.
Ash can block sunlight and affect the biosphere by reducing plant growth; gases can affect the hydrosphere through acid precipitation; ash can also settle onto the geosphere.
An animal survives winter by dramatically lowering its activity and metabolism. What is this called, and how does it help?
Dormancy; reduces energy/resource needs during unfavorable conditions
Grass → mouse → snake → hawk.
In the food chain above, if grass contains 60,000 kcal, how much energy reaches the hawk?
60 kcal
Cleaner fish remove parasites from larger fish. What interaction is this and what are the signs?
Mutualism; (+,+)
An animal lowers its body temperature and metabolic rate for a short period, often for only part of a day. What type of dormancy is this?
Torpor
Explain why the phosphorus cycle generally moves more slowly than the nitrogen cycle.
Phosphorus lacks a major atmospheric phase and is often stored in rocks/sediments, so weathering and geologic processes are slow
Compare tundra and boreal forest: which factor most strongly explains why boreal forest supports taller vegetation?
Warmer temperatures/longer growing season
A disturbance removes most primary consumers but leaves producers intact. Predict one likely direct effect on producers and one on secondary consumers.
Producers increase; secondary consumers decrease
A cattle egret follows grazing cattle and eats insects that the cattle disturb. What interaction is this and what are the signs?
Commensalism; (+,0)
What is the largest reservoir of nitrogen on Earth?
The atmosphere
A dead organism releases nitrogen back into soil, then bacteria convert it to nitrate. Name the two processes in order.
Ammonification → nitrification
Box turtles burrow deep into soil, leaf litter, or woodland substrate to ride out freezing conditions. What type of dormancy is this an example of?
Brumation
A food web loses a top predator (tertiary consumer). Predict what would happen in each of the 3 lower trophic levels.
Secondary consumers would overpopulate, causing primary consumers to decrease and producers to overpopulate.
A symbiotic relationship is a close, long-term interaction between two different species. Competition and predation are not considered symbiotic because they do not involve organisms living in a close, long-term association.
Which sphere contains the greatest amount of Earth’s carbon?
The geosphere