Science: Biology

Genetic variation provides a lot of different traits. It is essential to the survival of all species as if all individuals were the same, a species would be in danger of extinction.

Continuous variation is when traits cannot be sorted into distinct classes, but fall into a series of overlapping classes. E.g. Height, nose size, hair length.

Discrete variation is when traits show distinct or 'either or' variation. E.g. eye color, whether someone can roll their tongue.

Sex cells are called gametes. Fertilized sex cells and developing embryo are called zygotes.

Homozygous means the same (like homosexuals) and heterozygous means different.

A dominant allele will always be expressed and a recessive allele will only be expressed if the other allele that makes up the gene is recessive.

An allele codes for a gene.

Genotype are what alleles make up the gene and Phenotype is the physical expression of the gene.

A gonad.