Key Ecosystem terms - Community, Abiotic, Biotic, Niche
Laura Armstrong & Joe Wolfensohn
Teachers
Contents
Recall Questions
This topic requires some prior knowledge of Ecology from GCSE as well as Biodiversity from year 12. You can test your knowledge on these below.
What is the basic unit of classification in ecology?
A species.
Which term describes all organisms of a particular species in one area at a particular time?
Population.
What are non-living factors that affect ecosystems called?
Abiotic factors.
Topic Explainer Video
Check out this @JoeDoesBiology video that explains key ecosystem terms - community, abiotic, biotic, niche or read the full notes below. Once you've gone through the whole note, try out the practice questions!
Definitions
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Species: A group of organisms that can interbreed to produce fertile offspring.
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Population: All the organisms of one species living in a particular area at a given time. As they are all one species, they can interbreed to produce fertile offspring.
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Community: All the populations of different species living and interacting in a habitat at a given time.
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Habitat: The place where an organism lives.
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Ecosystem: A community and the abiotic conditions that influence it. Ecosystems can be small (e.g., a pond) or large (e.g., a forest).
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Abiotic Factor: A non-living factor that affects living organisms and ecosystems (e.g., temperature, pH, light intensity).
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Biotic Factor: A living factor that affects population size or distribution (e.g., competition, predation, disease).
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Niche: The role of a species within its ecosystem, including its habitat, food source, and interactions. Each species has a unique niche.
Key Relationships
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An ecosystem is shaped by interactions between biotic and abiotic factors.
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Species interact through food webs, competition, and symbiosis, forming complex communities.
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Organisms are adapted to their niches, and no two species can occupy exactly the same niche in the same habitat long-term (this is known as the competitive exclusion principle).
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You must understand how populations interact with their environment and with other organisms to form dynamic ecosystems. This links directly with core concepts in energy transfer and succession.
Exam Tip
Students often confuse habitat and niche. A habitat is where an organism lives, the niche is how it lives there and it’s role within the ecosystem.
No answer provided.
Define the term "niche" and explain why no two species can occupy the same niche in the same habitat. (3 marks)
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Niche refers to the role of a species in an ecosystem.
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It includes the biotic and abiotic conditions the organism needs.
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Two species cannot occupy the same niche in the same habitat because one will outcompete the other (competitive exclusion principle).
Practice Question
Try to answer the practice question from the TikTok on your own, then watch the video to see how well you did!