Energy
If a producer starts with 10,000 units of energy, about how much energy will reach the secondary consumer? (Use the 10% rule.)
100 units of energy (kcal)
Corn plants are eaten by mice, which are eaten by snakes, which are eaten by owls.
Which is the secondary consumer?
Snakes
You visit a desert and notice cacti, lizards, sand, and high temperatures. Which are the abiotic factors?
sand and high temperatures
A student wants to test how different amounts of sunlight affect plant growth. What is the independent variable?
The amount of sunlight the plants receive
If a forest has trees, deer, wolves, and mountain lions, Identify the primary consumer.
Deer
If a plant has 300,000 units of energy, about how much energy would reach a hawk (tertiary consumer)?
300 units of energy (kcal)
In the food chain: Grass → Grasshopper → Frog → Snake → Hawk, which is the tertiary consumer?
Snake
A pond has fish, algae, frogs, rocks, and dissolved oxygen. Which are the biotic factors?
Fish, algae, frogs
A scientist tests if music affects how fast hamsters run on a wheel. What should the scientist measure as the dependent variable?
Speed of hamsters
In an ocean food web, algae are eaten by zooplankton, which are eaten by small fish. If overfishing removes most of the small fish, what might happen to the zooplankton population?
Zooplankton populations will increase - they have much less predators around
Why does the amount of energy available to a tertiary consumer tend to be much smaller than what’s available to a primary consumer?
10% of available energy moves up through each trophic level
In an ocean food web, phytoplankton are eaten by krill, which are eaten by fish, which are eaten by seals, which are eaten by sharks. What trophic level is the seal?
tertiary consumer
A hurricane destroys part of a coastal forest. Is the hurricane a biotic or abiotic factor?
abiotic
Students test if the type of liquid (water, soda, juice) affects how fast seeds germinate. What should they keep constant?
Amount of liquid given, location of seeds, sunlight on seeds, etc
Rabbits eat plants, and foxes eat rabbits. If a drought reduces plant growth, what happens to the fox population? Explain the chain reaction.
Rabbits will decrease because their food (plants) have died off. As the rabbits starve and die, the foxes then lose their food source. We will see the chain reaction create a loss of foxes in the environment.
If 10% of the energy moves up through each consumer, what is the other 90% being used for in organisms?
Breathing, digesting, reproducing, and other processes that keep the organism alive
Grass → Grasshopper → Frog → Snake. If the grasshoppers die off due to pesticide use, which organisms in the chain would be most immediately affected and why?
Frogs - lack of food!
If a new species of insect is introduced into a field, is that a biotic or abiotic change to the ecosystem?
Biotic
A teacher sets up two fish tanks: one with fertilizer added and one without. Give a possible hypothesis for this experiment.
If _________, then __________. (answers vary)
In a food web, owls eat mice, snakes, and insects. If insect populations double, how might this affect the owl population?
In a grassland ecosystem, there are many grasses but fewer hawks. How do trophic levels explain this pattern?
There is less energy available as you go up the trophic levels, and big animals (higher trophic levels) require a lot of energy (kcals) to keep them alive. There can only be so many higher level consumers supported.
A farmer sprays pesticide to kill insects in a field. The insects are primary consumers that eat the crops. Predict how this might affect secondary consumers in the food web.
The secondary consumers would lose their food source (the insects) and we would see the secondary consumer population decline.
Runoff from fertilizer kills some fish in the nearby lake. These dead fish are…. (biotic or abiotic).
Biotic - the dead fish are no longer alive, but were once living.
We see a student in a Maine South tank top running outside of the school at 3:30 pm and we assume he is on the Cross Country team. Is this an observation or inference?
Inference
Why are producers (plants, algae) the most important part of the food chain?
They are the primary energy source for the rest of the ecosystem; they are able to photosynthesize energy from sunlight into edible energy for consumers!