adaptation
a change due to natural selection
allele
one of several different versions of a gene, as in having an a, b, or o blood type allele
altruism
sacrifice of one's self for the benefit of another individual
chromosome
rodlike structures in the cell nucleus that house an individual's genes
dominance
a feature of an allele that will determine a phenotype in either the homozygous or heterozygous condition
epigenetics
the study of gene-environment interactions in the production of phenotypes
evolution
descent with modification from a common ancestor
fitness
the ability of one genotype to reproduce more successfully relative to other genotypes
gene
specific areas on a strand of dna that carry hereditary information
gene expression
the process in which genetic instructions are converted into a feature of a living cell
genetic drift
change in a population's genes from one generation to the next due to chance or accident
genotype
an individual's profile of alleles
heritability
the statistical likelihood that variations observed in a population are due to genetics
heterozygous
having two different alleles for a gene
homozygous
having two of the same alleles for a gene
identical twins
twins who develop from a single egg and have identical genes
migration
movement to a new location
mutation
errors that occur when dna is replicated
natural selection
the process by which survival and reproduction pressures act to change the frequency of alleles in subsequent generations
nature
the contributions of heredity to our physical structure and behaviors
nurture
the contributions of environmental factors and experience to our physical structure and behaviors
phenotype
an organism's observable characteristics
recessiveness
a feature of an allele that will only produce a phenotype in the homozygous condition
reciprocal altruism
help you provide another person when you expect the person to return the favor in the future
relatedness
the probability that two people share the same allele from a common ancestor
sexual selection
the development of traits that help an individual compete for mates