6-Community Ecology 1

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Questions and Answers

What term describes the total number of species in a community?

Species distribution

Species evenness

Species abundance

Species richness (correct)

In the context of competition, which type of competition is generally more intense within the same species?

Intraspecific competition (correct)

Interpersonal competition

Predator-mediated competition

Interspecific competition

Which example illustrates mutualism in nature?

Brown and green anoles competing for insects

Corals fighting for space on the reef

Dominant plant species overshadowing others

Clownfish providing protection to sea anemone (correct)

What is the significance of predator-mediated species coexistence?

It allows weaker competitors to survive. Signup and view all the answers

Species evenness relates to which of the following?

The relative abundance of each species Signup and view all the answers

What is the primary focus of community ecology?

The interactions and abundance of coexisting species Signup and view all the answers

Which term describes a group of populations of different species living close enough to interact?

Biological community Signup and view all the answers

What type of species interaction is characterized by one species benefiting while the other is harmed?

Predation Signup and view all the answers

Which of the following interactions is considered beneficial for both species involved?

Mutualism Signup and view all the answers

What concept describes the role of a species within its ecosystem, including its habitat and interactions?

Niche Signup and view all the answers

What differentiates a fundamental niche from a realized niche?

Fundamental niche is broader than realized niche due to competition. Signup and view all the answers

What is species diversity measured by?

Species richness and species evenness Signup and view all the answers

Which type of species interaction has a positive effect on one species and no effect on another?

Commensalism Signup and view all the answers

What is the primary reason in a population with logistic growth that dN/dt declines over time?

Intraspecific competition Signup and view all the answers

Which principle states that two species cannot coexist indefinitely on the same limiting resource?

Competitive Exclusion Principle Signup and view all the answers

In terms of niches, what differentiates the fundamental niche from the realized niche?

The realized niche is broader and includes all biotic interactions. Signup and view all the answers

What is resource partitioning?

The division of resources among species to minimize competition. Signup and view all the answers

Which of the following factors are considered limiting resources for populations?

Food, space, and water Signup and view all the answers

Character displacement refers to which of the following?

The adaptive evolution of species traits to reduce resource overlap. Signup and view all the answers

What outcome is suggested by Gause's experiments on species coexistence?

Coexistence typically requires resource partitioning. Signup and view all the answers

Which of the following best defines a niche?

The specific requirements of a species regarding its resources. Signup and view all the answers

Study Notes

Community Ecology I

Community ecology studies the distribution and abundance of coexisting species and their interactions.
A biological community is a group of different species populations living close enough to interact.
Plants, animals, and microbes are connected through interactions like predation, competition, and mutualism.
Communities are often defined by their dominant life form and spatial characteristics.

Types of Interactions

Mutualism (+/+): Both species benefit.
Predation (+/-): One species benefits (predator), while the other is harmed (prey).
Parasitism (+/-): One species benefits (parasite), while the other is harmed (host).
Herbivory (+/-): An animal (herbivore) consumes a plant (herb).
Competition (-/-): Individuals of both species are harmed as they compete for limited resources. Interspecific (between species) or intraspecific (within the species).
Commensalism (+/0): One species benefits, while the other is neither harmed nor helped.
Amensalism (-/0): One species is harmed, while the other is neither harmed nor helped.

What is a Niche?

A niche is the set of all requirements of a species regarding resources and physical conditions.
A niche can be represented by axes such as foraging height, light level, and food size.

Niche Concept

Fundamental niche: The niche an organism would occupy in the absence of other species.
Realized niche: The niche an organism occupies in the presence of other species.
Competition and presence of other species may cause the realized niche to be smaller or differ from the fundamental niche.

Gause's Principle

Competitive Exclusion Principle: Two species cannot coexist indefinitely on the same limiting resource (Gause 1934).
Species cannot occupy the same niche.

Species Coexistence

Coexistence of species is the norm.
Resource partitioning: Species minimize competition by using resources in slightly different ways or at different times.
Character displacement: Competition can drive the evolution of traits like beak size in species.
Predator-mediated coexistence: A weaker competitor may persist in the presence of a stronger competitor due to a predator targeting the stronger competitor.
Facilitated coexistence: Species may cohabit in the same environment using the same resources. However, they occupy different areas within that environment.

Species Diversity

Species richness: Total number of species in a community.
Species evenness: Relative abundance of each species.
Higher diversity means more species, and they are relatively abundant.

Mutualisms

Mutualisms are considered "biological markets," involving nutritional exchange, protection, or transport.
Examples include corals and clownfish, mycorrhizae, ant-plant relationships, pollination, and seed dispersal.

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Description

Test your knowledge on community ecology and the various interactions among species. This quiz covers key concepts such as mutualism, predation, parasitism, and competition, exploring how these relationships shape biological communities. Hone your understanding of how different species coexist and interact within their environments.