Biologoy B1b AQA Summary Notes

The revision notes I made for my Biology exam in Year 10, hope they are useful :)

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  • Created on: 05-04-12 13:02
Preview of Biologoy B1b AQA Summary Notes

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AQA GCSE Biology ­ Unit 1 summary notes
11.5 Adaptation and Competition
To survive, organisms require a supply of materials from their surroundings and from the other
living organisms there.
Organisms live, grow and reproduce in places where, and at times when, conditions are suitable.
Physical (abiotic) factors:
Living (biotic) factors:
Competition ­ for: food, light, water, space.
Competition in Animals
Animals often compete with each other for:
Competition in Plants
Plants often compete with each other for:
Water from the soil
Nutrients from the soil
Organisms have features (adaptations) which enable them to survive in the conditions in which
they normally live
The organisms that are best adapted to make use of their resources in a habitat are more likely
to survive and increase in numbers
For example:
o To be able to obtain a certain food better.
o To make it more difficult for predators or grazing animals to catch them or eat them. E.g.
thorns, poisons and warning colours to deter predators.
o To survive in extreme climates, e.g. arctic or deserts
Their adaptation will effect their abundance compared to other populations in a habitat
Examples of extreme adaptations:
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AQA GCSE Biology ­ Unit 1 summary notes
The camel can go without food and water for 3 to 4 days.
Fat stored in their humps provides long term food reserve, and a supply of metabolic water.
The fat is not distributed around the body; this reduces insulation, allowing more heat loss.
They are tall and thin, increasing their surface area to volume ratio, increasing heat loss by
Polar Bear
Polar bear has thick fur and fat beneath its skin to insulate it.…read more

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AQA GCSE Biology ­ Unit 1 summary notes
11.6 Reproduction and Variation
Genetic material
A cell is the basic unit of life; all organisms are made up of cells.
The nucleus is a large organelle found in all cells, that contains the genetic information. (Even
red blood cells once had a nucleus).
DNA (Deoxyribose nucleic acid) is the chemical found in the nucleus of all cells that contains
the genetic information.…read more

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AQA GCSE Biology ­ Unit 1 summary notes
Humans can carry out various procedures to create clones of plants and animals.
These new individuals (clones) are genetically identical to the parents.
New plants can be produced quickly and cheaply by taking cuttings from older plants.
Tissue culture
This uses small groups of cells from part of a plant to grow new plants.
They are grown in special growth media that provides all the essential nutrients and conditions
for growth.…read more

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AQA GCSE Biology ­ Unit 1 summary notes
Genetic engineering
Genes from the chromosomes of humans and other organisms can be cut out using enzymes and
transferred to cells of other organisms.
GM = Genetically modified
Examples of uses in food production:
GM soya
GM tomatoes
Enzymes used to make vegetarian cheese
Examples of uses in medicine:
Vaccine production
Production of Factor VIII for haemophiliacs
Example in detail: Insulin production for diabetics.…read more

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AQA GCSE Biology ­ Unit 1 summary notes
Other uses of genetic engineering
Genes can also be transferred to the cells of animals or plants at an early stage in their development
so that they develop with desired characteristics:
Gene therapy in could be used to insert healthy genes into foetuses that would otherwise
develop a genetic disease.
Genes can be inserted into clumps of plant cells, so that the adult plant can produce a
chemical that kills pests.…read more

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AQA GCSE Biology ­ Unit 1 summary notes
11.7 Evolution
The theory states that all species of living things which exist today have evolved from simple
life-forms which first developed more than 3 billion years ago.
Origins of life
These first organisms were very simple single-celled organisms, similar to bacteria.
However, these rarely survive as fossils.
Scientists cannot be certain about how life began on Earth.
Fossils provide evidence of how much (or how little) different organisms have changed since life
developed on Earth.…read more

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AQA GCSE Biology ­ Unit 1 summary notes
Most mutations are harmful or fatal. Occasionally, some mutations are useful.
How do mutations occur?
o Errors occur when the DNA is replicated prior to cell division:
o Errors may occur when chromosomes are separated during cell division:
What do mutations do?
Genes control the synthesis of proteins.
Therefore a change in a gene or a new sequence of genes can result in different proteins being
Different proteins can change a characteristic.
E.g.…read more

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AQA GCSE Biology ­ Unit 1 summary notes
11.8 Human's Effect on the Environment
Human Population Explosion
The human population is growing rapidly due to an increase in the standard of living.
Waste Production
Raw materials including non-renewable energy resources are rapidly being used up and
increasingly more waste is produced.
Unless waste is properly handled, more pollution will be caused.…read more

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AQA GCSE Biology ­ Unit 1 summary notes
Waste may pollute:
water with sewage, fertiliser or toxic chemicals;
air - with smoke and gases such as sulphur dioxide;
Land - with toxic chemicals, such as pesticides and herbicides, which may be washed from
land into water.
Sulphur dioxide contributes to acid rain:
It dissolves in the rain forming sulphuric acid.
This damages the leaves and the roots of trees.
Rivers and streams become acidic.
Aquatic plants and animals may die.…read more


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