Chapter 8 Understanding Populations

1. A relationship in which two organisms live in close association is called _____________.

Symbiosis refers to a close and long-term interaction between two different species, where both organisms benefit from the relationship. It can take different forms, such as mutualism (both organisms benefit), commensalism (one organism benefits while the other is unaffected), or parasitism (one organism benefits while the other is harmed). In symbiotic relationships, the organisms rely on each other for survival, reproduction, or other advantages.

Explanation

Symbiosis refers to a close and long-term interaction between two different species, where both organisms benefit from the relationship. It can take different forms, such as mutualism (both organisms benefit), commensalism (one organism benefits while the other is unaffected), or parasitism (one organism benefits while the other is harmed). In symbiotic relationships, the organisms rely on each other for survival, reproduction, or other advantages.

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2. A relationship in which one species benefits and the other speices is neither harmed nor helped is called ____________.

Commensalism is a type of symbiotic relationship where one species benefits while the other species is neither harmed nor helped. In this relationship, the benefiting species gains an advantage, such as obtaining food or shelter, without causing any harm or providing any benefit to the other species involved. This type of interaction is often seen in nature, where one organism takes advantage of the resources or activities of another organism without affecting it positively or negatively.

Explanation

Commensalism is a type of symbiotic relationship where one species benefits while the other species is neither harmed nor helped. In this relationship, the benefiting species gains an advantage, such as obtaining food or shelter, without causing any harm or providing any benefit to the other species involved. This type of interaction is often seen in nature, where one organism takes advantage of the resources or activities of another organism without affecting it positively or negatively.

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3. Exponential growth is where a population grows faster and faster.

True

False

Exponential growth refers to a pattern where a population increases at an accelerating rate over time. This means that the growth rate itself is growing, resulting in a rapid increase in population size. Therefore, the statement that exponential growth is where a population grows faster and faster is correct.

Explanation

Exponential growth refers to a pattern where a population increases at an accelerating rate over time. This means that the growth rate itself is growing, resulting in a rapid increase in population size. Therefore, the statement that exponential growth is where a population grows faster and faster is correct.

4. Ants and acacia tress have a mutualistic relationship because

They are both adapted to a humid climate.

They benefit each other.

The ants eat part of the acacia tree.

Ants and acacia trees have a mutualistic relationship because they benefit each other. The ants protect the acacia tree from herbivores by attacking and warding off any potential threats. In return, the acacia tree provides shelter and food sources for the ants, such as nectar and specialized structures called Beltian bodies. This mutually beneficial relationship allows both species to thrive and survive in their environment.

Explanation

Ants and acacia trees have a mutualistic relationship because they benefit each other. The ants protect the acacia tree from herbivores by attacking and warding off any potential threats. In return, the acacia tree provides shelter and food sources for the ants, such as nectar and specialized structures called Beltian bodies. This mutually beneficial relationship allows both species to thrive and survive in their environment.

5. The unique role of a species within an ecosystem is its predation.

True

False

The given statement is false. The unique role of a species within an ecosystem is not its predation. Predation is just one of the many possible roles a species can have within an ecosystem. Other roles can include being a producer, a decomposer, or a competitor for resources. Each species plays a unique role in maintaining the balance and functioning of the ecosystem.

Explanation

The given statement is false. The unique role of a species within an ecosystem is not its predation. Predation is just one of the many possible roles a species can have within an ecosystem. Other roles can include being a producer, a decomposer, or a competitor for resources. Each species plays a unique role in maintaining the balance and functioning of the ecosystem.

6. Biotic potential is the slowest rate at which a population can grow.

True

False

Biotic potential refers to the maximum rate at which a population can grow under ideal conditions, not the slowest rate. Therefore, the given statement is incorrect.

Explanation

Biotic potential refers to the maximum rate at which a population can grow under ideal conditions, not the slowest rate. Therefore, the given statement is incorrect.

7. Which of the following is an example of coevolution?

Flowers that can be pollinated by only one species of insect.

Rabbits that invade a new habitat.

Bacteria that suddenly mutate in a lab.

Coevolution refers to the reciprocal evolutionary changes between two or more species that interact with each other. In this case, the flowers and the insect species have likely evolved together over time. The flowers have developed specific traits that attract and accommodate only one species of insect for pollination, while the insect has likely adapted its behavior or physical characteristics to efficiently pollinate these flowers. This mutual adaptation between the flowers and the insect is an example of coevolution.

Explanation

Coevolution refers to the reciprocal evolutionary changes between two or more species that interact with each other. In this case, the flowers and the insect species have likely evolved together over time. The flowers have developed specific traits that attract and accommodate only one species of insect for pollination, while the insect has likely adapted its behavior or physical characteristics to efficiently pollinate these flowers. This mutual adaptation between the flowers and the insect is an example of coevolution.

8. The growth rate of a population of geese will probably increase within a year if

More birds die than are hatched.

Most females lay two eggs instead of three during their nesting season.

Several females begin laying eggs at younger ages than their mothers did.

If several females begin laying eggs at younger ages than their mothers did, it means that there will be more females reproducing at an earlier age. This will result in an increase in the number of eggs being laid and therefore an increase in the number of geese being hatched. As a result, the growth rate of the population of geese will probably increase within a year.

Explanation

If several females begin laying eggs at younger ages than their mothers did, it means that there will be more females reproducing at an earlier age. This will result in an increase in the number of eggs being laid and therefore an increase in the number of geese being hatched. As a result, the growth rate of the population of geese will probably increase within a year.