17 & 18 Evolution + Genetic Engineering

Variation

The difference between individuals of the same species.

Species

A group of organisms that can interbreed and produce fertile offspring

Heredity

The passing on of characteristics from one generation to the next e.g. eye colour is passed

Inherited variation

Differences between individuals that are controlled by genes.

Acquired variation

Differences within a species that develop over the lifetime of the organism

Causes of genetic variation

Sexual Reproduction

Meiosis

Mutations

Mutation

Is a change in the amount or structure of DNA

Gene Mutation

Are changes in a single gene e.g. sickle cell anaemia

Chromosome mutations

Are large changes in the structure or number of one or more chromosomes.

Example of gene mutation

Cystic fibrosis

Example of chromosome mutation

Downs Syndrome

Mutagens

Agents that cause mutation

Examples of mutagens

X-Rays

Radiation

Chemicals from cigarette smoke

UV light

Evolution

The changes between members of a species and the emergence of new species from older species over time, in response to change in the environment, due to natural selection.

Natural selection

The mechanism by which members of a species, with genetic traits that allow them to survive in their environment, reproduce and pass these traits to the next generation.

Evidence for evolution

1. Fossils

2. Comparative anatomy

3. Comparative embryology

4. Comparative biochemistry

Comparative anatomy

Comparing the structures found in different groups of organisms

Scientists who developed theory of evolution by natural selection

Charles Darwin & Alfred Russell Wallace

Genetic engineering

The manipulation and alteration of genes

Stages in genetic engineering

1. Isolating the DNA

2. Cutting the DNA

3. Attaching the cut DNA to a vector piece of DNA

4. Transforming the target organism

5. Cloning the transformed organism

6. Getting the introduced gene expressed