Biodiversity flashcards (OCR Biology Unit 2)

These are some flashcards on biodiversity which cover the points for the OCR specification

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  • Created by: Tas K
  • Created on: 23-03-12 14:18
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Speciesa group of individual organisms very similar Levels of biodiversity:
in appearance, anatomy, physiology, biochemistry Range of habitats in which different species live
and genetics, whose members are able to All species are different from each other
interbreed freely to produce fertile offspring. There is genetic variation between individuals
belonging to the same species
Habitat the place where an organism lives
Biodiversity ­ the variety of lifethe range of living
organisms to be found
Sampling: Randomising Samples:
Observe all species present * Prepare a table before sampling
Identify them
Count them Spot species
List species
Alternatively, count number of each species in a Randomly choose positions of sample sites to
small area of a habitat and multiply to make an avoid bias
estimate Take samples at regular distances across the
habitat
Reduces bias, more reliable
Sampling Plants: Using TRANSECTS:
Using QUADRATS: Line Transect:
Either estimate abundance ­ Stretch a long piece of rope across a habitat and
Abundant record down the number of species touching the
Common rope, repeat at intervals
Frequent Only samples a small area
Obvious
Rare Belt Transect:
Less accurate Place a quadrat beside the line and move it along the
Or measure percentage cover line to study the area
More accurate Allows the user to sample a larger area
Sampling animals: PITFALL TRAP:
SWEEP NETTING: A trap set in the soil to catch small animals
Walking through a habitat with a stout net which
sweeps any small animals. After emptying the
contents of the net onto a white sheet, each species
can be identified.
Can't sample large animals, animals may escape
In rainy weather, the observer needs to be cautious to
cover the lid so that it doesn't fill up

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COLLECTING FROM TREES: TULLGREN FUNNEL:
Spread a white sheet under a tree and knock a Put leaf litter into a funnel and light up so that as the
branch with a stout stick. The animals will drop onto leaves dry, the animals fall to the bottom to be
the sheet and identify and count them. collected.…read more

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FUNGI PLANTS
The body consists of a myceliuma network of Are autotrophsit makes its own food from simple
numerous strands called hyphae organic molecules i.…read more

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Adaptation Natural selection
Any variation that helps an organism to survive DARWIN'S 4 OBSERVATIONS
BEHAVIOURAL 1. offspring generally appear similar to parents
e.g cactus closes stomata when little water is 2. no 2 individuals are identical
3. organisms have the ability to produce large numbers of
available
offspring
PHYSIOLOGICAL/ BIOCHEMICAL
4. Populations in nature tend to remain fairly stable in size
e.…read more

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