Ecological Niche and Keystone Species

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What is the primary function of a keystone species in an ecosystem?

To compete with other species for resources
To modify the physical environment to benefit other species
To disperse seeds to other areas of the ecosystem
To maintain the diversity of species within a specific ecosystem (correct)

What determines the characteristics of an individual organism?

The genes it possesses (correct)
The niche it occupies
The species to which it belongs
The population to which it belongs

What is the primary outcome of natural selection on a species?

Increased genetic diversity within the population
Decreased competition for resources among individuals
Determination of which individuals will reproduce and pass their genes (correct)
Evolution of a new species from an existing one

What is the term for the ways an organism affects its environment and interacts with other organisms?

Species interaction (A) Signup and view all the answers

What is the difference between a population and a species?

A population is a smaller unit of organization than a species (B) Signup and view all the answers

What is the role of bison in American tall grass prairie ecosystems?

To allow smaller plant species to be successful (B) Signup and view all the answers

What is the primary mechanism driving the increase in favorable variations in a population over time?

Differential access to resources resulting from individual variation (A) Signup and view all the answers

What type of competition occurs between members of the same species?

Intraspecific competition (D) Signup and view all the answers

Which of the following is NOT a result of the process of natural selection?

Increase in population size (A) Signup and view all the answers

What is the approximate percentage of species that have gone extinct?

98-99% (C) Signup and view all the answers

What is the competitive exclusion principle?

The principle that no two species can occupy the same ecological niche in the same place at the same time (B) Signup and view all the answers

What is the term for the production of new species from previously existing species?

Speciation (D) Signup and view all the answers

What is an example of parasitism?

Fleas living on the surface of a host (A) Signup and view all the answers

Which of the following is an example of coevolution?

The development of antibiotic resistance in bacteria (D) Signup and view all the answers

What is the main difference between ectoparasites and endoparasites?

The location on the host's body where they live (D) Signup and view all the answers

What type of symbiotic relationship is characterized by one species benefiting and the other species not being affected?

Commensalism (D) Signup and view all the answers

What is the main reason why most offspring in a population do not survive?

Insufficient resources (C) Signup and view all the answers

What is the term for a close, long-lasting, physical relationship between two different species?

Symbiosis (D) Signup and view all the answers

What is the primary function of carbon sinks in the carbon cycle?

To remove carbon atoms from active, short-term nutrient cycles (D) Signup and view all the answers

What is the impact of burning fossil fuels on the carbon cycle?

It releases carbon atoms that were removed from the active, short-term carbon cycle (B) Signup and view all the answers

What is the role of nitrogen-fixing bacteria in the nitrogen cycle?

To convert nitrogen gas into ammonia (A) Signup and view all the answers

What is the primary sink for nitrogen in the nitrogen cycle?

The atmosphere (D) Signup and view all the answers

What is the result of excessive application of nitrogen or phosphorus as fertilizer?

An increase in the growth rate of bacteria and algae (C) Signup and view all the answers

What is the role of denitrifying bacteria in the nitrogen cycle?

To convert nitrite into nitrogen gas (B) Signup and view all the answers

What is the primary characteristic of a mutualistic relationship?

Both species benefit, and the relationship is obligatory (B) Signup and view all the answers

What is the main difference between a community and an ecosystem?

A community is a group of interacting species, while an ecosystem includes the physical environment (B) Signup and view all the answers

What is the role of decomposers in an ecosystem?

To use nonliving organic matter as a source of energy and raw materials (D) Signup and view all the answers