Keystone species
This type of species has a large effect on its ecosystem, even if its population is small.
Keystone Species
Which of the following is an autotroph in a food chain?
A. Grass
B. Rabbit
C. Snake
D. Hawk
A. Grass
Energy is pass down through tropic levels.
True or false?
False
Which of the following best describes primary succession?
A. Succession that occurs after a forest fire, where soil is already present
B. Succession that begins on bare rock with no soil
C. Succession that happens quickly in an established ecosystem
D. Succession that only occurs in aquatic environments
B. Succession that begins on bare rock with no soil
This is the maximum number of individuals an environment can support.
Carrying Capacity
Which of the following is an example of a keystone species that helps maintain wetland ecosystems?
A. Beaver
B. Deer
C. Grass
D. Earthworm
A. Beaver
Which statement correctly describes a food web?
A. It shows only one path of energy transfer.
B. It shows multiple feeding relationships and energy paths in an ecosystem.
C. It shows energy moving from animals to plants.
D. It only includes decomposers.
B. It shows multiple feeding relationships and energy paths in an ecosystem.
In an energy pyramid, which level contains the most energy?
A. Tertiary consumers
B. Secondary consumers
C. Primary consumers
D. Producers
D. Producers
Secondary succession happens faster than primary succession because this is already present.
Soil
A lack of food, water, or space are examples of these.
Limiting Factors
Sea otters are considered a keystone species in kelp forest ecosystems. They eat sea urchins, which feed on kelp. What is the most likely effect if sea otters are removed from the ecosystem?
A. The sea urchin population will decrease, and kelp forests will grow larger.
B. The kelp population will increase, and sea urchins will disappear.
C. The sea urchin population will increase, and kelp forests will decline.
D. The kelp and sea urchin populations will stay the same.
C. The sea urchin population will increase, and kelp forests will decline.
In a food web, if one species is removed, the arrows connected to it show:
A. How its removal affects the flow of energy to other organisms
B. Which species will immediately die
C. The exact number of organisms that will increase
D. Nothing, arrows are decorative
A. How its removal affects the flow of energy to other organisms
Which of the following best describes why energy decreases at higher trophic levels in an energy pyramid?
A. Organisms at higher levels do not eat
B. Energy is lost as heat, movement, and waste at each level
C. Producers store all the energy and do not share it
D. Secondary consumers take energy from tertiary consumers
B. Energy is lost as heat, movement, and waste at each level
After a hurricane destroys a forest but leaves the soil intact, what type of succession is likely to occur?
A. Primary succession
B. Secondary succession
C. Tertiary succession
D. Climax succession
B. Secondary succession
Which factor could increase the carrying capacity of a pond ecosystem?
A. Pollution reduces oxygen levels in the water.
B. Introducing more fish than the pond can support.
C. Adding aquatic plants that provide food and shelter.
D. A drought that lowers water levels.
C. Adding aquatic plants that provide food and shelter.
Wolves were reintroduced to Yellowstone National Park. Over time, the elk population decreased, and plant life along rivers increased. What role do wolves play in this ecosystem?
A. Primary producers
B. Keystone species
C. Invasive species
D. Decomposers
B. Keystone species
In the food chain grass → rabbit → fox → hawk, the arrow between the rabbit and the fox shows:
A. The rabbit eats the fox
B. Energy flowing from the fox to the rabbit
C. Energy flowing from the rabbit to the fox
D. That the fox avoids the rabbit
C. Energy flowing from the rabbit to the fox
In an energy pyramid, only about 10% of energy is passed from one trophic level to the next. If plants contain 10,000 kcal of energy, approximately how much energy would be available to secondary consumers?
A. 1,000 kcal
B. 100 kcal
C. 10 kcal
D. 500 kcal
B. 100 kcal
Which organisms are usually the first to colonize an area during primary succession? Pioneer Species
A. Trees and shrubs
B. Lichens and mosses
C. Fish and amphibians
D. Large mammals
BONUS: Why are they important?
B. Lichens and mosses
If a population reaches the carrying capacity of its environment, what is likely to happen?
A. The population will grow indefinitely.
B. The population will decrease due to limited resources.
C. The population will be unaffected.
D. Resources will increase to support the population.
B. The population will decrease due to limited resources.
Why are keystone species important to an ecosystem?
A. They are always the largest animals in the ecosystem.
B. They prevent any other species from living in the area.
C. Their presence helps maintain the structure and balance of the ecosystem.
D. They always produce the most food for other organisms.
C. Their presence helps maintain the structure and balance of the ecosystem.
DDT is a chemical that can build up in the bodies of organisms. As it moves up the food chain from small fish to large fish to eagles, its concentration increases. This process is called:
A. Photosynthesis
B. Biomagnification
C. Respiration
D. Eutrophication
B. Biomagnification
Mercury accumulates in small fish at 2 ppm (parts per million). Larger fish eat the small fish, and eagles eat the larger fish. Which statement describes biomagnification in this food chain?
A. Mercury decreases as it moves up the food chain.
B. Mercury stays the same at each level.
C. Mercury increases at each higher trophic level.
D. Mercury is eliminated by the top predator.
C. Mercury increases at each higher trophic level.
What is the final stable stage of succession called, when the ecosystem has reached balance?
A. Pioneer community
B. Intermediate community
C. Climax community
D. Disturbance community
C. Climax community
A forest can support up to 500 deer. If the deer population exceeds this number, food becomes scarce and some deer die. Which of the following statements is true?
A. The forest’s carrying capacity is 500 deer, and food is a limiting factor.
B. The forest’s carrying capacity is unlimited, and food is not a limiting factor.
C. The deer population can keep growing without any effect on resources.
D. Limiting factors do not affect carrying capacity.
A. The forest’s carrying capacity is 500 deer, and food is a limiting factor.