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Biology B1b keyword list
3.5 Billion
How many years ago the first life forms appeared.
Acid Rain
Consequence of air which has been polluted by sulphur dioxide or nitrogen oxides.
Adaptations
Special features of organisms that help them to survive in their particular habitat and
way of life.
Adult Cell Cloning
Technique in which the nucleus of a body cell is transplanted into an egg cell whose
own nucleus has been removed. This creates an embryo whose genes are identical
to those of the body cell donor.
Allele
Different versions of a gene- for example the tongue rolling gene has 2: 'roller' and
'non-roller'
Asexual
Rapid type of reproduction where only one parent is involved, which passes on all of
its genes to the offpsring. These are therefore CLONES of each other and of the
parent.
Biodiversity
A measure of how much richness of life there is in an ecosystem. Some of the
species may have potential uses as building materials, textiles or medicines.
Body Cell
Cells other than gametes. They contain 2 copies of each chromosome (and therefore
of each gene).
Chromosome
Long thread-like structure found in the nucleus. Made of DNA wrapped around
proteins, they carry hundreds of genes spaced out along their length.
Climate Change
A probable consequence of the greenhouse effect. May lead to sea levels rising.
Competition
This occurs when organisms of the same or different species all try to access the
same limited resource.
Cuttings
Technique for producing small numbers of plant clones by cutting off a sideshoot and
dipping it in hormones to stimulate roots to form at the cut end.
Darwin
The founder of the theory of Natural Selection
Deforestation
Causes habitat loss and increase in atmospheric CO2 levels due to reduced
photosynthesis and burning/decay of the cut-down plant material.
DNA ligase
Enzyme which 'pastes' fragments of DNA back together.
Embryo Transplants
Method of cloning animals by splitting embryos into several parts and reimplanting
them into surrogate mothers. The offspring are identical to each other, but NOT to
either parent.
Extinction
When all members of a species die out, which may be due to changes in
environment, new predators, new diseases or new competitors.
Fossil
Impression of dead animal or plant left behind in rocks, which can provide evidence
about evolutionary histories.
Gamete
Sex cell, e.g. sperm, egg, pollen, ovum. They contain only one copy of each
chromosome (and therefore of each gene.)
Gene
A length of DNA which tells the cell how to make one particular protein
Genetic Engineering
The process of transferring individual genes from one organism to another, which
may be of a different species.
Greenhouse Effect
Where the Earth's surface temperature is warmer than expected because of gases in
the atmosphere reflecting heat back down to the surface rather than letting it escape
into space.
Habitat
The place where an organism lives
Habitat Destruction
Humans reduce the amountof land available for other species by building, quarrying,
farming and dumping waste.
Herbivore
Animal which eats only plant material
Indicator Species
An organism which is sensitive to pollution, so can be used to estimate pollution
levels in different areas.
Lamarck
Proposed a theory to explain evolution which depended on organisms passing on
characteristics they had acquired during their lifetimes.
Lichen
Small organism, consisting of an alga and a fungus working together. They are good
indicators of air pollution.
Methane
A gas produced by cattle and paddy fields of rice, which causes the greenhouse
effect more strongly than carbon dioxide.
Mutation
A random change in the base sequence of a gene which may lead to harmful or
beneficial effects on the organism which carries it. These are essential as sources of
variation which can then allow evolution.
Natural Selection
A process which leads to evolution because not all members of a population are
equally likely to pass on their genes to each new generation.
Pollution
The release of harmful materials into the environment.
Predator
Animal which is carnivorous, i.e. it eats other animals
Prey
An animal eaten by a predator
Restriction Enzymes
Type of enzyme which allows you to cut DNA for genetic engineering purposes.
Sexual
Type of reproduction which involves male and female parents producing gametes.
Because it involves bringing together new combinations of genes, it leads to
variation.
Sustainable
Development which allows us to improve the quality of life for people without causing
problems for future generations.
Tissue Culture
Technique for producing huge numbers of plant clones from a single parent by taking
tiny fragments and growing them in laboratory conditions.