Community-Structure

Community Ecology – Definition, Examples, Structure + MCQs

Overview

The larger unit of the population is the community.

    • Communities have many characteristics that are not in the population.
    • Communities vary in size, habitats, and number of populations in them.
    • Large communities are independent and self-sufficient but small communities depend on large ones and are greatly influenced by adjacent communities.
    • Ecologists classify communities on different bases.
  • The communities may be classified as forests, grasslands, logs, deserts, etc. depending on growth, size of vegetation, and organisms.
  • The communities that are growing through succession or changes are called seral communities and stable communities are called climax communities.
  • The species that are dominant in a community and have controlling influence are called ecological dominants.
Community Ecology

Among the earliest formal meanings of community, ecology was recommended by Cornell teacher Robert Whittaker in 1975. Whittaker identified community ecology as an assemblage of living organisms that connect and form a community with a unique structure and species composition.

Community-Ecology

Definition of Community Ecology

Community ecology is the study of the organization and functioning of communities of organisms. As populations of species interact with one another, they form biological communities. A community of organisms includes all the interacting populations of the species living within a specific area or within a specific habitat.

Community ecology also studies the relationships of the members of a community to their environment. Community ecology is usually subdivided according to habitat or biome.

Community Ecology Examples

Community ecology incorporates lots of types of environmental interactions that continue to change with time. A forest community consists of the plant community, all trees, birds, squirrels, deer, foxes, fungi, fish in a forest stream, insects, and all other species living there or migrating seasonally.

Likewise, a coral reef community consists of a huge variety of various species of corals, fish, and algae.

Indicators of Ecological Health

Species richness

Species richness is the variety of various species represented in an ecological community, landscape, or area. Species richness is merely a count of species, and it does not take into consideration the abundances of the species or their relative abundance distributions.

Species diversity

Species diversity is the number of different species that are represented in an offered community. The effective diversity of species refers to the number of similarly abundant species required to acquire the very same mean proportional species abundance as that observed in the dataset of interest.

Ecological Community Structure

All biological communities have a similar structure called a trophic pyramid. Each pyramid includes four or five levels. Food energy is passed from one level to the next along a food chain. Considering that energy is lost to heat at each level in the pyramid, it takes lots of organisms at a given trophic level to support those in the next level up.

The base of the pyramid in every biological community is composed of species called autotrophs, organisms that gather sunlight (or in unusual cases, heat) directly through photosynthesis (or chemosynthesis). All other organisms in the pyramid are called heterotrophs.

Ecological-Community

A food chain represents the flow of food energy in a community. For example, phytoplankton is consumed by fish that may be captured and cooked by a human. Only 10 percent of the energy consumed is transferred at each trophic level, which is why the energy pyramid is not inverted. Decomposers contribute by breaking down dead organisms to release nutrients back into the environment.

Further Reading:  Carbohydrates - An Introduction

Community-Structure

Types of Interactions in Ecological Community

Mutualism:

It is the relationship between two organisms in which both the organisms benefit from each other. Lichens are an example of mutualism between a fungus and an alga.

The relationship between insects and flowering plants is another example. The insects get nectar from the flower; the flowers have the ability to reproduce because the insects carry pollen from flower to flower.

Commensalism:

In this kind of relationship, only one organism benefits from the relationship. The other is not affected at all. For example, sharks might have little fish called remoras attached to them. As the shark feeds, the remoras pick up the scraps. The remoras benefit from this relationship, the shark is not affected at all.

Parasitism:

This is an association between a host and a parasite, which involves supplying the parasite with food, protection, and conditions for its survival. The parasite might or may not damage the host. Diseases in living organisms, which are triggered by parasites are called invasions. Parasites might be ectoparasites, living outside the body of the host e.g., the fungus causing dandruff in hair, and endoparasites, living inside the body of the host e.g., tapeworm in the intestine of humans.

Predation:

An animal that preys on other animals is a predator. A predator is a consumer. The animal that is captured and eaten is the prey. The overall procedure is called predation.

Competitors: two species fight over minimal resources.

Species in Community Ecology

Foundation species, like coral in a coral reef community, play an essential role in community ecology and forming structure.

Keystone species like wolves exceptionally impact community structure relative to the abundance of the other species. If eliminated, the loss of crucial predators drastically alters the whole community.

Invasive species are intruders that are foreign to the environment and interrupt the community. Numerous kinds of intrusive species like the Zebra Mussel, damage native species. Invasive species proliferate and minimize biodiversity, which compromises the general animal and plant community within that specific niche.

MCQs on Community Ecology

  1. What is the larger unit of population in ecology?
    • a) Organism
    • b) Community
    • c) Habitat
    • d) Ecosystem

    Answer: b) Community

  2. How do large communities differ from small ones in terms of dependence?
    • a) Large communities depend on small ones
    • b) Small communities are independent
    • c) Both are independent
    • d) Both depend on each other

    Answer: a) Large communities depend on small ones

  3. What are communities classified as based on growth and size of vegetation?
    • a) Seral and climax
    • b) Large and small
    • c) Independent and dependent
    • d) Forests and grasslands

    Answer: a) Seral and climax

  4. Which term is used for species dominant in a community with controlling influence?
    • a) Dominant species
    • b) Ecological dominants
    • c) Alpha species
    • d) Primary species

    Answer: b) Ecological dominants

  5. Who recommended the term “community ecology”?
    • a) Charles Darwin
    • b) Robert Whittaker
    • c) Gregor Mendel
    • d) Rachel Carson

    Answer: b) Robert Whittaker

  6. What does community ecology study?
    • a) Interactions between planets
    • b) Organization and functioning of communities
    • c) Stellar formations
    • d) Geological structures

    Answer: b) Organization and functioning of communities

  7. Which example represents a forest community?
    • a) Coral reef
    • b) Tundra
    • c) Desert
    • d) Forest stream with trees, birds, and insects

    Answer: d) Forest stream with trees, birds, and insects

  8. What does species richness represent?
    • a) Abundances of species
    • b) Variety of species
    • c) Mean proportional abundance
    • d) Specific species abundance

    Answer: b) Variety of species

  9. What is the primary base of the trophic pyramid in a biological community?
    • a) Heterotrophs
    • b) Consumers
    • c) Autotrophs
    • d) Decomposers

    Answer: c) Autotrophs

  10. How much energy is transferred at each trophic level in a food chain?
  • a) 25%
  • b) 50%
  • c) 75%
  • d) 10%
Further Reading:  Phylum Arthropoda - Animals with Jointed Legs

Answer: d) 10%

  1. Which type of interaction benefits both organisms involved?
  • a) Commensalism
  • b) Parasitism
  • c) Mutualism
  • d) Predation

Answer: c) Mutualism

  1. In commensalism, how is the organism that benefits affected?
  • a) Positively
  • b) Negatively
  • c) Not affected
  • d) Both positively and negatively

Answer: c) Not affected

  1. What is the relationship between a host and a parasite called?
  • a) Mutualism
  • b) Commensalism
  • c) Parasitism
  • d) Predation

Answer: c) Parasitism

  1. What is the term for an animal that preys on other animals?
  • a) Consumer
  • b) Predator
  • c) Prey
  • d) Invasive species

Answer: b) Predator

  1. Which species play a crucial role in community ecology and structure, like coral in a coral reef?
  • a) Keystone species
  • b) Invasive species
  • c) Foundation species
  • d) Dominant species

Answer: c) Foundation species

 

FAQs on Community Ecology

  1. What is the larger unit of population in ecology?
    • Answer: The larger unit of population in ecology is a community.
  2. How do large communities differ from small ones in terms of dependence?
    • Answer: Large communities are independent and self-sufficient, while small communities depend on large ones and are influenced by adjacent communities.
  3. How are communities classified by ecologists?
    • Answer: Ecologists classify communities based on different criteria, such as forests, grasslands, logs, deserts, etc., depending on growth, size of vegetation, and organisms.
  4. What are seral communities and climax communities?
    • Answer: Communities undergoing changes are called seral communities, while stable communities are called climax communities.
  5. What are species dominant in a community with controlling influence called?
    • Answer: The species that are dominant in a community with controlling influence are called ecological dominants.
  6. Who introduced the term “community ecology”?
    • Answer: The term “community ecology” was introduced by Cornell teacher Robert Whittaker in 1975.
  7. What does community ecology study?
    • Answer: Community ecology studies the organization and functioning of communities of organisms, including their interactions and relationships within specific areas or habitats.
  8. Can you provide examples of community ecology?
    • Answer: Examples include a forest community with trees, birds, squirrels, and other species, and a coral reef community with a variety of corals, fish, and algae.
  9. What are the indicators of ecological health?
    • Answer: Indicators include species richness, representing the variety of species, and species diversity, indicating the number of different species in a community.
  10. Describe the ecological community structure in terms of a trophic pyramid.
    • Answer: The ecological community structure includes a trophic pyramid with four or five levels, representing the flow of food energy from autotrophs (base) to heterotrophs.
  11. How much energy is transferred at each trophic level in a food chain?
    • Answer: Only 10 percent of the energy consumed is transferred at each trophic level in a food chain.
  12. What are the types of interactions in an ecological community?
    • Answer: Types of interactions include mutualism (beneficial to both), commensalism (beneficial to one, unaffected other), parasitism (parasite benefits, host may be harmed), predation (predator consumes prey), and competition (two species fight for resources).
  13. What role do foundation species and keystone species play in community ecology?
    • Answer: Foundation species, like coral in a coral reef, play a crucial role in forming the structure of a community. Keystone species, like wolves, can significantly impact community structure, and their removal can alter the entire community.
  14. What are invasive species, and how do they affect communities?
    • Answer: Invasive species are foreign intruders that disrupt native communities. They proliferate, reduce biodiversity, and compromise the overall animal and plant community within a specific niche.
Further Reading:  Plants and Fungi [Protista - Euglenoids, Dinoflagellates, Diatoms and More]

Wrap up: Community Ecology – Definition, Examples, Structure

The tutorial provides a comprehensive exploration of Community Ecology, covering various aspects essential for understanding the dynamics of biological communities. Here’s a concise summary:

  1. Overview:
    • Defines the community as a larger unit of population with unique characteristics, varying in sizes, habitats, and populations.
    • Highlights the independence of large communities and the dependency of small communities on adjacent ones.
  2. Community Ecology:
    • Introduced by Robert Whittaker, community ecology is defined as the study of the organization and functioning of communities of organisms.
    • Emphasizes the classification of communities based on habitat or biome.
  3. Community Ecology Examples:
    • Illustrates community ecology through examples like forest and coral reef communities.
    • Explores the diversity of species within these communities, including trees, birds, fish, and algae.
  4. Indicators of Ecological Health:
    • Describes species richness as the count of species and species diversity as the number of different species in a community.
    • Emphasizes the importance of effective diversity in understanding species abundance.
  5. Ecological Community Structure:
    • Introduces the trophic pyramid structure common to all biological communities.
    • Explains the flow of food energy along a food chain and the roles of autotrophs and heterotrophs.
  6. Types of Interactions in Ecological Community:
    • Covers mutualism, commensalism, parasitism, predation, and competition as key interaction types.
    • Provides examples such as lichens, relationships between insects and flowering plants, and predator-prey dynamics.
  7. Species in Community Ecology:
    • Highlights the roles of foundation species, keystone species, and invasive species.
    • Stresses the significant impact of keystone species on community structure.
  8. Conclusion:
    • Concludes with the understanding that community ecology is vital for comprehending the intricate relationships between species and their environments.
    • Encourages further exploration of related topics to deepen ecological knowledge.