SB4 - Natural Selection and Genetic Modification

Key Words

Evolution

A gradual change in the characteristics of a species over time

Genetic Variation

the characteristics of an individual vary (due to differences in genes)

Natural Selection

the variations of some individuals that make them better at coping with the change than others, and are more likely to survive (‘survival of the fittest’)

Inheritance

the survivors breed and pass on their variations to their offspring. So the next generation contains more individuals with the ‘better adapted variation’

Pentadactyl Limb

vertebrates have limbs with five fingers suggesting that they share a common ancestor

Domains:

Archaea, Bacteria, Eukarya

Archaea

cells with no nucleus, genes contain unused sections of DNA

Bacteria

cells with no nucleus, no unused sections in genes

Eukarya

cells with a nucleus, unused sections in genes

Artificial Selection

Humans choose certain organisms because they have useful characteristics

Selective Breeding

Breeding organisms together because of their desirable traits to produce offspring with those traits.

Disease Resistance

how well an organism copes with diseases

Yield

how much useful product is made

Genetic Engineering

Involves changing the DNA of an organism by inserting the genes from another organism

Differentiate

become specialised

Tissue Culture

The growing of cells or tissues in a liquid containing nutrients

Callus

a clump of undifferentiated cells

Clones

identical copies

Alleles

different forms of the same gene

Plasmids

small circles of DNA

Vector

Any DNA molecules used to carry new DNA into another cell

Extinction

when a species dies out

Biological Control

Using organisms to kill problem organisms, such as pests or weeds

Weeds

plants that cause problems

Pollution

Harm caused to the environment