phenotype variation and key defintions

phenotype variation is influenced by: [include examples]

-genetic factors

→blood group

→ eye colour

-environmental factors

→diet in animals (poor nutrition can reduce growth)

→etiolation in plants (in dark conditions, plants grow a long stem bcs they’re searching for light)

Inherited characteristics that show continuous variation are usually influenced by_____

Inherited characteristic that show discontinuous variation are usually influenced by _____

-many genes (polygenic)

-one gene (monogenic)

genotype

the alleles an organism has for a gene

phenotype

observable characteristics of an organism

homozygous

organism carries two copies of the same allele

heterozygous

organism carries two different alleles

dominant alleles

an alleles that is always expressed in the phenotype

recessive alleles

an allele that is only expressed in the phenotype if there are two copies of the recessive allele present (no dominant allele present)