Chapter 3 - Key Terms & Definitions

The Evolving Mind: Nature and Nurture Intertwined

Nature

• The contributions of our heredity to our physical structures & behaviours.

• Our heredity or innate predispositions

Nurture

• Our heredity or innate predispositions

Francis Galton

• Cousin of Charles Darwin

• First to produce the idea of Nature vs. Nurture

• The belief that “nature prevails enormously over nurture” (1883)

• Belief intelligence was largely the result of inheritance.

Genotype

• Someone’s profile of alleles.

Phenotype

• An observable characteristic that gets produced.

What does your genotype consist of?

Half by our mother’s egg and half by our father’s sperm.

How many set of chromosomes do each parent have?

23

Gene

• A smaller segment of DNA located in a particular place on a chromosome.

• Each gene contains instructions for making a particular type of protein.

Gene Expression

• Genetic instructions are used to produce a particular protein.

• The process in which genetic instructions are converted into a feature of a living cell.

Alleles

• One of several versions of a gene, as in having an A, B, or O blood type allele.

• Many alleles can occur for a given gene, but an individual receives only two—one from each parent.

• Combination of your two alleles create your blood type.

Homozygous

• Having two of the same alleles for a gene.

• (Ex: Both parents have brown hair = Child will have brown hair)

Homos

• “Same” in Greek

Heterozygous

• Having two different alleles for a gene.

• (Ex: The dad has freckles and the mom doesn’t = The child having freckles)

Hetero

• Means “different” in Greek)

Recessive

• A feature of an allele that produces a phenotype only in the homozygous condition.

Dominant

• A feature of an allele that determines a phenotype in either the homozygous or the heterozygous condition.

The Effects of Dominant and Recessive Genes

Relatedness

• Defined as the probability that two people share copies of the same allele from a common ancestor.

Intersex

• Is an umbrella term used to describe individuals who are born with sex characteristics (including genitals, gonads, and chromosome patterns) that do not fit typical binary notions of male or female bodies.

Thale Cress

• Humans sharing other similar genes with chimpanzees, mice, fruit flies, yeast, & this weed.

Candidate Genes

• Genes that have a greater rate of interest rather than other genes.

Behavioural Genetics

• Amount of heritability

• Investigates the strength of genetic influences on a particular behaviour.

• (Ex: Variations in loneliness across the population appear to be strongly influenced by genetics.)

Molecular Genetics

• Candidate Genes

• (Ex: Certain genes seem to impact loneliness more than others.)

Functional Genomics

• Links between the global genome and particular traits.

• (Ex: Genes might be expressed differently in lonely and nonlonely individuals.)

Gene-Environment Interactions

• Candidate genes have different effects in different situations.

• (Ex: Candidate genes seem to have more impact on loneliness in some environments compared to others.)

Heritability

• Is the statistical likelihood that variations observed across individuals in a population are due to genetics.

Concordance Rates

• The statistical probability that a trait in one person will be shared by another; usually discussed in relation to identical and fraternal twins.

Genome-wide Association Studies (GWAS)

• A scan of complete sets of DNA from many participants, which is performed to look for variations associated with a particular phenotype, condition, or disease.

MAOA (monoamine oxidase A) gene

Is an enzyme that affects several important neurochemicals, including dopamine and serotonin

Epigenetic

• The study of gene–environment interactions in the production of phenotypes.

• Epi is Greek for “Over” or “Above”

• Refers to the reversible development of traits by factors that determine how genes perform.

Histones

• Protein structures around which your dna is wound.

Evolution

• Descent with modification from an ancestor.

Natural Selection

• The process by which survival and reproduction pressures act to change the frequency of alleles in subsequent generations.

• Organisms that survive long enough to reproduce would pass their traits to the next generation.

• Organisms that did not reproduce would not have the opportunity to pass their traits to future generations.

Gregor Mendel (1822–1884)

• Who discovered ways to predict the inheritance of particular traits, like the colour of flowers, in his research on pea plants

Mutation

• An error that occurs when DNA is replicated.

Migration

• Occurs when organisms move from one geographical place to the next.

• Movement to a new location.

Genetic Drift

• Change in a population’s genes from one generation to the next because of chance or accident.

Fitness

• The ability of one genotype to reproduce more successfully relative to other genotypes.

• Interaction between characteristics and the environment in which they exist.

Adaptation

• The process or result of change because of natural selection.

• Can take many forms.

Hominin

• Species that walked on 2 feet.

• Creatures who evolved large brains and considerable intelligence.

Functionalism

• Behaviour is seen as promoting survival, as opposed to being random and pointless.

Altruism

• One individual’s self-sacrifice is designed to benefit another individual.

Reciprocal Altruism

• Occurs when we help another individual who’s likely to return the favour at some future date.

Sexual Selection

• Darwin’s term for the development of traits that help an individual compete for mates.

• The development of traits that help an individual compete for mates.

Intra

• Means “within”

Inter

Means “between”