Species and communities 4.1
This is a quiz of multiple choice style questions about species and communities for topic 4.1
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What is the characteristic feature of all members of a species?
Species are "groups of organisms that can potentially interbreed to produce fertile offspring".
When a species is divided into several populations separated by a physical barrier they may be prevented from repoducing, even though they are potentially able to interbreed.
What is the name given to this situation?
Members of a species may be reproductively isolated in separate populations.
What is the term used to describe organisms which feed on other living organisms?
Species can be autotrophic or heterotrophic in nutrition (a few species are both).
Consumers are heterotrophs that feed on living organisms by ingestion.
The image below shows a community of plants and microorganisms living in a sealed glass jar.
Why can the community live for so long without adding any inorganic nutrients to the system?
Autotrophs obtain inorganic nutrients from the abiotic environment. Heterotrophs get nutrients by eating other organisms, but this is not the reason why the community is sustainable.
The supply of inorganic nutrients is maintained by nutrient cycling.
Ecosystems have the potential to be sustainable over long periods of time
The organisms in the photo below are the species, Common Rough Woodlice (Porcellio scaber)
These small invertebrates feed on dead plant material under rocks and in soil.
Which of the following classifications do they belong in?
Classifying species using their mode of nutrition can be done by remembering that consumers eat living organisms, and both detritivores and saprotrophs feed on dead organisms.
The suffix 'vore" (Latin vorāre “to devour") implies eating greedily, and Woodlice can do this.
Saprotrophs is a term which comes from the Greek word saprós, meaning “putrid”. Fungi, excrete digestive enzymes and absorb nurtients, which turns the substrate putrid. As they don't have any mouthparts fungi don't "eat greedily!"
Mesocosms can be used by ecologists to investigate natural systems.
What advantage is there in using mesocosms rather than the natural environment for these experiments?
Mesocosms can allow the control of variables much more than the natural environment.
In an experiment in a small garden, five quadrat frames were used to sample the flowers.
How should the quadrats be positioned in an ecological study like this, to test for an association between two species?
For example in an ecosystem the distribution of chosen species should be sampled using Random quadrat sampling
Which of the following diagrams best represents the relationship between an ecosystem and a community?
A community is "populations of different species living together and interacting with each other."
An ecosystem is "a community and its interactions with the abiotic environment."
A community is a part of the ecosystem.