Chapter 3

What is nature vs nurture?

Nature refers to heredity or innate predispositions; nurture refers to environmental experiences. Both interact to shape behavior.

Who coined the term “nature versus nurture”?

Francis Galton (1869), cousin of Charles Darwin.

What is a genotype?

Your personal set of genetic instructions that interacts with the environment to produce a phenotype.

What is a phenotype?

An observable trait resulting from genotype and environment.

What is relatedness?

The probability that two people share copies of the same allele from a common ancestor.

What are sex chromosomes?

X and Y chromosomes that determine biological sex and carry different genes.

What is behavioural genetics?

The study of how genetics and environment influence behavior (e.g., heritability, twin studies).

What is heritability?

The statistical likelihood that variation in a population is due to genetics (not applied to individuals).

What are twin studies used for?

To measure concordance rates—the probability that a trait in one twin appears in the other.

What are adoption studies used for?

To separate genetic from environmental influences by comparing adopted children to biological and adoptive parents.

What is epigenetics?

The study of how the environment influences gene expression (turning genes on or off).

Give an example of environmental influence on genes.

Stress, diet, smoking, and exercise can alter whether a gene is expressed.

What is a gene?

A sequence of DNA in a specific chromosome location containing instructions to make proteins.

What is gene expression?

The process where information from a gene is used to produce a protein.

What is an allele?

One of two or more versions of a gene (e.g., blood type alleles A, B, O).

What does homozygous mean?

Having two of the same alleles for a gene (SS or LL).

What does heterozygous mean?

Having two different alleles for a gene (SL).

What is a dominant allele?

An allele expressed even if only one copy is present.

What is a recessive allele?

An allele expressed only when two copies are present.

What is the human genome?

The complete set of genes, shaped by millions of years of evolution.

Define evolution.

Descent with modification from a common ancestor.

What is natural selection?

Traits that improve survival and reproduction become more common in future generations.

What is a mutation?

A random change in DNA sequence due to replication errors or external factors.

What is migration in evolution?

Movement of organisms from one geographical area to another.

What is genetic drift?

Random changes in allele frequencies due to chance or accident.

Define fitness.

The ability of one genotype to reproduce more successfully than others in a specific environment.

Define adaptation.

A change in a population that makes it better suited to its environment.

Give an example of adaptation.

Dark moths becoming more common in polluted areas.

What is evolutionary psychology?

The study of how evolutionary principles shape behavior.

What is cooperation?

Working together for mutual benefit (e.g., hunters cooperating to catch prey).

What is altruism?

Helping another at a cost to oneself (e.g., protecting someone else from danger).

What is reciprocal altruism?

Helping someone with the expectation they’ll return the favor later.

What is sexual selection?

Evolutionary pressures related to attracting and competing for mates.

What is culture in this context?

Shared beliefs and behaviors that influence how nature and nurture interact.

What is the difference between genotype and phenotype?

Genotype = genetic code; phenotype = observable result of that code plus environment.

What are candidate genes?

Genes believed to have greater influence on specific traits.

What are GWAS (Genome-Wide Association Studies)?

Scans of DNA from many participants to find genetic variations linked to specific traits.

What are the main mechanisms of evolution?

Mutation, natural selection, migration, and genetic drift.

What is the contemporary human brain shaped by?

Evolutionary adaptations to complex social behavior.

What is reciprocal altruism an example of?

An adaptive social behavior shaped by evolution.