Question

The primary source of energy in most ecosystems is/are(1 point)
Responses

the sun.
the sun.

heterotrophs.
heterotrophs.

autotrophs.
autotrophs.

glucose.

Answer 1

Which would be an autotroph in a grassland ecosystem?(1 point)
Responses

prairie cordgrass
prairie cordgrass

monarch butterfly
monarch butterfly

muskrat
muskrat

mallard duck
mallard duck

Answer 2

Which of the following best explains why there are fewer secondary consumers than producers?(1 point)
Responses

More secondary consumers can absorb radiant energy from the sun.
More secondary consumers can absorb radiant energy from the sun.

Around 10% of the energy is transferred to support the next trophic level.
Around 10% of the energy is transferred to support the next trophic level.

Heat energy given off from producers kills off primary and secondary consumers.
Heat energy given off from producers kills off primary and secondary consumers.

Secondary consumers have less cell processes that need energy.

Answer 3

Which trophic level ingests the most biomass in order to receive the energy they need?(1 point)
Responses

primary consumers
primary consumers

secondary consumers
secondary consumers

producers
producers

tertiary consumers

Answer 4

Wolves were reintroduced to Yellowstone National Park in 1995. They began to hunt the abundant elk population, so elk numbers decreased. The elk carcasses provided food for other predators, like foxes, coyotes, and bears, so all of their populations increased. Elk used to overgraze on willow plants; now that willows are growing back, beaver numbers are increasing, because they prefer the slow-moving water that willows cause.

Which of these species is a keystone species?

(1 point)
Responses

willows
willows

elk
elk

wolves
wolves

bears

Answer 5

The primary source of energy in most ecosystems is **the sun**.

Answer 6

In a grassland ecosystem, an example of an autotroph would be **prairie cordgrass**. Autotrophs are organisms that produce their own food, typically through photosynthesis, which is what prairie cordgrass does.

Answer 7

The statement that best explains why there are fewer secondary consumers than producers is: **Around 10% of the energy is transferred to support the next trophic level.**

This concept is known as the "10% rule," where only about 10% of the energy from one trophic level is converted into biomass and available to the next level, leading to fewer organisms as you move up the food chain.

Answer 8

The trophic level that ingests the most biomass in order to receive the energy they need is the **primary consumers**. Primary consumers, which are herbivores, consume a large amount of plant biomass (the producers) to obtain the energy necessary for their survival.

Answer 9

The keystone species in this scenario is the **wolves**. Keystone species have a disproportionately large impact on their ecosystem relative to their abundance, and the reintroduction of wolves played a crucial role in controlling the elk population, which in turn affected several other species and the overall ecosystem dynamics.