Question

1 multiple choice 20 points
which of the following represents a population?
a single lion living in the savanna.
the trees, soil, and air in a forest.
all the fish, algae, and insects in a lake.
all the grizzly bears in a forest.
2 multiple choice 20 points
a forest fire destroys a large portion of a grassland. a biologist observes that while the grass population is severely reduced, the population of rabbits that eat the grass also begins to decline. this scenario best describes a relationship between which two levels of organization?
community and biosphere
organism and ecosystem
ecosystem and biosphere
population and community
3 multiple choice 20 points
an aquatic biologist compares a pond community to a pond ecosystem. what key difference would they analyze to compare these two levels?
the number of individual fish in the pond.
the different species of plants and animals found in the pond.
the amount of sunlight, the temperature of the water, and the ph of the soil.
the interactions between predators and prey in the pond.
4 multiple choice 20 points
an ecologist is studying a salt marsh and collects data on the number of crabs, the concentration of salt in the water, and the types of plants growing there. this data is best used to create a model of a(n):
community
ecosystem
organism
population
5 multiple choice 20 points
a sudden, prolonged drought impacts a desert region, leading to a decline in plant diversity and the subsequent decline of animal populations that depend on the plants. based on this, which conclusion best evaluates the relationship between the \ecosystem\ and \community\ levels in this scenario?
the community and ecosystem are independent and do not affect one another.
a change in one population in the community caused the drought.
the change in the ecosystem (the drought, an abiotic factor) caused a subsequent change in the community (a biotic factor), demonstrating that the health of an ecosystem dictates the health of its community.
the community changed first, causing the drought to occur and affecting the ecosystem.

Explanation:

• Question 1: A population is a group of individuals of the same species. A single lion is an individual, trees, soil, and air are an ecosystem (biotic and abiotic), fish, algae, insects are a community (different species). All grizzly bears (same species) in a forest is a population.
• Question 2: Grass population (population level) and rabbit population (population level) which is part of a community. But the key is population (grass) and community (rabbits as part of a community that depends on grass).
• Question 3: A community is all the living organisms (different species). An ecosystem includes biotic (living) and abiotic (non - living like sunlight, water temperature, soil pH) components.
• Question 4: An ecosystem includes biotic (crabs, plants) and abiotic (salt concentration) factors.
• Question 5: The drought (abiotic, part of the ecosystem) caused a change in the community (plant and animal populations).

Answer:

1. D. All the grizzly bears in a forest.
2. D. Population and Community.
3. C. The amount of sunlight, the temperature of the water, and the pH of the soil.
4. B. Ecosystem.
5. C. The change in the ecosystem (the drought, an abiotic factor) caused a subsequent change in the community (a biotic factor), demonstrating that the health of an ecosystem dictates the health of its community.