Populations have a genetic structure defined by its gene pool's allele and genotype frequencies

Population

all individuals of the SAME species living in the SAME place at the SAME time

Species

a group of populations that have the POTENTIAL to INTERBREED

Genes

are carried on CHROMOSOMES and control the INHERITANCE of traits such as flower colour in plants and fur colour in animals

Alleles

ALTERNATE form of a gene

Phenotype frequency

the proportion of a population with a PARTICULAR PHENOTYPE; expressed as a decimal or a percent

Allele Frequency

the RATE of OCCURRENCE of a particular ALLELE in a population, expressed as a decimal.

The frequency of alleles vary greatly from WHAT to WHAT and WHAT to WHAT

The frequency of alleles vary greatly from ALLELE to ALLELE and POPULATION to POPULATION

For example, the allele for O type blood and Rh⁺ is much more frequent in Canadian populations , red hair: Irish and Scottish; dark hair and blue eyes: Italians; cystic fibrosis:  Caucasian; sickle cell anemia:  African.

The frequency of alleles may stay very WHAT within a population (population WHAT) or may be changing WHAT (population WHAT)

The frequency of alleles may stay very STABLE within a population (population EQUILIBRIUM) or may be changing RAPIDLY (population EVOLUTION)

Diploid organisms have HOW MANY possible alleles for every WHAT therefore the total number of alleles in a population is WHAT the number of individuals.

Diploid organisms have 2 possible alleles for every GENE therefore the total number of alleles in a population is TWICE the number of individuals.