Biology · OCR Paper 2
Monitoring and Maintaining the Environment
How we monitor living things and look after biodiversity: sampling organisms with quadrats and transects, estimating population size by scaling up and by capture-recapture, the positive and negative effects of humans on biodiversity, the benefits and challenges of conserving it, and how changes in water and atmospheric gases affect where organisms live. Matches OCR GCSE Biology A (Gateway Science) B6.1a to B6.1d. The first four lessons are for both Combined Science and separate Biology. The last lesson, Environmental Change and the Distribution of Organisms, is for the Higher tier and separate Biology only.
Lessons
Ticks are remembered on this device only.
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1
Sampling Organisms: Quadrats and Transects
You cannot count every daisy on a school field, so ecologists count a small part of it and use that to describe the rest. This lesson is for both Combined…
11 terms -
2
Estimating Population Size
How many woodlice live in a garden, or daisies on a playing field? Nobody can count them all, but you can estimate. This lesson is for both Combined Science…
9 terms -
3
Human Interactions and Biodiversity
Humans are part of every ecosystem they live in, and what they do can destroy biodiversity or protect it. This lesson is for both Combined Science and separate…
10 terms -
Knowledge organiser
The whole chapter on a page or two of A4 — to revise from on screen or print.
Key terms in this chapter
All 30, gathered from every lesson.
- Abundance
- The number of individuals of a species in an area or habitat.
- Distribution
- Where in a habitat a species is found.
- Quadrat
- A square frame that marks off a known area for sampling.
- Transect
- A line across a habitat, along which samples are taken at regular intervals.
- Random sampling
- Taking samples at positions chosen by chance, to avoid bias.
- Systematic sampling
- Taking samples at regular intervals along a line.
- Pooter
- A device for collecting small insects by sucking them into a jar through a tube, without harming them.
- Percentage cover
- An estimate of the percentage of the ground in a quadrat that a species covers.
- Identification key
- A series of paired statements used to identify an organism from its features.
- Bias
- A systematic error that makes a sample unrepresentative.
- Sample
- A small part of a habitat or population that is studied, to represent the whole.
- Population size
- The number of individuals of a species living in an area.
- Estimate
- An approximate value, found by calculation from a sample.
- Scaling up
- Using the mean of a sample to calculate the total for a whole area.
- Capture-recapture
- A method for estimating the size of an animal population by catching, marking, releasing and catching again.
- Marked
- Given a harmless mark so that the animal can be recognised if it is caught again.
- Assumption
- Something that has to be true for a method to give a valid result.
- Percentage cover
- An estimate of the percentage of the ground in a quadrat that is covered by a species.
- Reliable
- Giving similar results when repeated, so that the result can be trusted.
- Sustainable
- Used in a way that does not use up or damage the resource for the future.
- Biodiversity
- The variety of living organisms in a habitat, or on Earth.
- Deforestation
- The clearing of large areas of forest, usually to use the wood or the land.
- Overharvesting
- Taking animals or plants faster than they can reproduce.
- Pollution
- The release of substances that harm living things into the air, water or land.
- Eutrophication
- The growth of algae in water, caused by extra nutrients, which leads to a loss of oxygen and the death of animals.
- Introduced species
- A species brought by humans to a place where it did not live before.
- Conservation
- Protecting and managing species and habitats so that biodiversity is not lost.
- Captive breeding
- Breeding rare animals in zoos or reserves, so that they can be released into the wild.
- Sustainable
- Used in a way that does not use up or damage a resource, so it lasts for the future.
- Indicator species
- A species whose presence or absence shows the level of pollution or the quality of the environment.