Population Growth

An abiotic or biotic condition which impacts the size of the population. 

• Limiting Factor

• Carrying Capacity

• Logistic Growth

• Exponential Growth

Answer explanation

A limiting factor is any abiotic or biotic condition that restricts the size of a population. It can include resources like food, water, and space, which directly affect population growth.

Tags

NGSS.MS-LS2-1

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If there is no immigration or emigration, how do the birth rate and the death rate affect population size?

• A. When the birth rate and the death rate remain the same, the population size does not change.

• B. When the birth rate and the death rate remain the same, the population size continues to increase.

• C. When the death rate exceeds the birth rate, the population shrinks.

• D. When the death rate exceeds the birth rate, the population increases.

Answer explanation

When the birth rate and death rate are equal, the population size remains stable (Choice A). If the death rate exceeds the birth rate, the population will decrease (Choice C). Thus, both A and C are correct.

In an ecosystem, buffalo eat grass, and bears prey upon the buffalo. What would happen to the buffalo and bear populations if the grass population declined dramatically?

• The buffalo population would decrease and the bear population would increase.

• The buffalo population and the bear population would increase.

• The buffalo population and the bear population would decrease.

• The buffalo population would increase and the bear population would decrease.

Answer explanation

If the grass population declines, buffalo will have less food, leading to a decrease in their population. Consequently, with fewer buffalo to prey on, the bear population will also decrease due to lack of food.

Tags

NGSS.MS-LS2-1

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Which of the following statements describe logistic growth? Select all that apply.

• A. When graphed, it appears as a J-shaped curve.

• B. It occurs when individuals reproduce at a constant rate under ideal conditions.

• C. When graphed, it appears as an S-shaped curve.

• D. It occurs when factors in the environment limit the population growth.

Answer explanation

Logistic growth is characterized by an S-shaped curve (C) as it reflects population growth that levels off due to environmental limits (D). A J-shaped curve describes exponential growth, not logistic.

What factors affect carrying capacity? Select all that apply.

• quality of habitat

• growth rate

• predators in habitat

• presence of disease

Answer explanation

Carrying capacity is influenced by the quality of habitat, which provides resources; predators that can limit population size; and the presence of disease, which can reduce survival rates. Growth rate alone does not directly affect capacity.

Tags

NGSS.MS-LS2-4

What are factors that limit population growth and are caused by human activity? Select all that apply.

• cutting down trees in forest

• paving land for a road

• lava covering a habitat area

• agricultural runoff into water

Answer explanation

Cutting down trees, paving land, and agricultural runoff are human activities that disrupt ecosystems, reduce habitats, and pollute water, limiting population growth. Lava is a natural event, not caused by humans.

Tags

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What is a limiting factor whose effects are dependent on a population’s density?

• density-independent factor

• density-dependent factor

• law of the minimum

• habitat loss

Answer explanation

A density-dependent factor is one whose effects vary with population density, such as competition for resources or disease spread. In contrast, density-independent factors affect populations regardless of their density.

Which of the following statements about limiting factors are true? Select all that apply.

• A. Density-dependent factors are dependent on a population’s density.

• B. Density-dependent and density-independent factors are both dependent on population density.

• C. Density-dependent factors only affect small populations.

• D. Density-independent factors impact a population regardless of a population’s density.

Answer explanation

A is true because density-dependent factors, like competition and predation, vary with population density. D is also true as density-independent factors, such as weather, affect populations regardless of their density.

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NGSS.MS-LS2-4

Eutrophication can cause die-offs of plants and animals, leading to a decline in the number of species. What specifically causes this? Select all that apply.

• excess oxygen

• lack of nutrients

• decrease in oxygen

• excess nutrients

Answer explanation

Eutrophication leads to excess nutrients, causing algal blooms that deplete oxygen in the water. This decrease in oxygen results in die-offs of aquatic life, contributing to a decline in species diversity.

Tags

NGSS.MS-LS2-1

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What is the law of the minimum?

• A) Growth is dependent on the size of a population.

• B) Growth is not limited by the total amount of resources, but by the scarcest resource.

• C) Growth is not limited by the total amount of resources, but by the most abundant resource.

• D) Growth is limited by the total amount of resources.

Answer explanation

The law of the minimum states that growth is limited not by the total resources available, but by the scarcest resource. Therefore, option B is correct as it accurately reflects this principle.

Tags

NGSS.MS-LS2-1

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