Relationships
A bird perches on the back of a deer, eating ticks without harming the deer. What type of ecological relationship exists between the bird and the deer?
Mutualism
What is the original source of energy for most food webs?
The Sun
Plants take in carbon dioxide from the atmosphere for what process?
Photosynthesis
What type of organism carries out nitrogen fixation on legume roots?
Bacteria
What is the term for the variety of living things in an ecosystem?
Biodiversity
When two species of birds use same nesting site, what ecological relationship is this?
Competition
In a food chain grass → grasshopper → frog → snake, which organism is the secondary consumer?
The frog
Animals return carbon to the atmosphere by what process?
Cellular respiration
What process converts nitrogen in dead organisms back into ammonium, restarting the cycle?
Decomposition or ammonification
Invasive species
A rabbit eats grass, then the wolf eats the rabbit. Which ecological interaction describes the wolf and the rabbit?
Predation
If decomposers were removed from an ecosystem, what would happen to nutrients?
Nutrients would not be recycled back into the soil.
In a forest food web, carbon stored in tree biomass is released when trees are cut and burned. What process adds CO₂ to the atmosphere?
Combustion
After nitrogen fixation, what process allows for the nitrates to be absorbed by the plants?
Nitrification
In a pond food web, algae → minnows → bass → herons. Fertilizer runoff kills much of the algae. Which populations in the food web will decrease first?
Minnows (primary consumers)
Clownfish live among the stinging tentacles of sea anemones, gaining protection while the anemone is unharmed or even helped. What type of symbiotic relationship is this?
Commensalism
A farmer removes most top predators from a field ecosystem with three trophic levels. Which trophic level will likely overpopulate first?
Primary consumers (herbivores)
How does deforestation affect the carbon cycle?
Less carbon is absorbed which increases atmospheric carbon dioxide
What is a common product used by many businesses and homeowners that uses nitrogen, but in excess can cause pollution?
Fertilizers
In a forest food web, trees provide acorns for squirrels and deer. Wolves eat deer, and owls eat squirrels. If a disease drastically reduces the deer population, how might this indirectly affect the squirrel population?
Increase due to less competition for acorns
A wolf hunts and kills a deer for food. At the same time, vultures scavenge the leftovers of the carcass once the wolf is finished. What symbiotic relationship exist between the wolf and the deer and the wolf and the vulture?
Wolf and deer - Predation
Wolf and vulture - Commensalism
A food web in a marine ecosystem shows phytoplankton eaten by shrimp, which are eaten by fish, then seals, then sharks. If overfishing removes most of the fish, predict one indirect effect on the seal population.
Seal populations decrease because their food source is gone.
Carbon stored in fossil fuels has been locked underground for millions of years. Human use of these fuels rapidly releases this carbon into the atmosphere. What impact does this have on the carbon cycle?
An increase in carbon emissions in the atmosphere.
How do animals obtain nitrates?
By eating the plants.
In an Arctic food web, phytoplankton → zooplankton → fish → seals → polar bears. Melting sea ice reduces phytoplankton growth. Predict one long-term impact on polar bears and explain why.
polar bear populations decrease because reduced phytoplankton lowers energy flow through the entire food web, reducing seals (their prey)