Variation and Evolution

Classification

Placing objects into groups based on similar characteristics

Taxonomy

The science of classifying organisms

Species

A group of similar organisms that are capable of naturally interbreeding with each other to produce fertile offspring

Variation

Individuals in a species showing different characteristics. Can be acquired or inherited genetically.

Mutation

A spontaneous change in the amount or structure of DNA

Mutagens

Agents that cause mutations.

Gene/Point Mutation

A change in a single gene.

Chromosome Mutation

A large change in the structure or number of one or more chromosomes

Evolution

The way in which organisms change genetically over time to produce new life forms.

Natural Selection

The process by which organisms with advantageous genetically controlled characteristics will survive and reproduce.

Speciation

The production of new species as a result of evolution.

Paleontology

The study of fossils.

Fossil

The remains of an organism living a long time ago.

Gamete

Haploid cell capable of fusion

Fertilisation

The union of two gametes to form a single cell called a zygote

Alleles

Alternative forms of the same gene

Dominant

The allele prevents the recessive allele from being expressed

Recessive

The allele is prevented from being expressed by a dominant allele

Genotype

The genetic make-up of an organism

Phenotype

The physical make-up or appearance of an organism

Homozygous

Two alleles are identical

Heterozygous

Two alleles are different

Incomplete Dominance

Neither allele is dominant or recessive with respect to each other. Both alleles are expressed in an intermediate phenotype.

Linkage

Genes are located on the same chromosome