Chap 3 - Biology and Behavior

What is the genome?

The complete set of an organism’s genes.

What is the difference between genotype and phenotype?

• Genotype: inherited genetic material

• Phenotype: observable traits resulting from genotype and environment

What does polygenic inheritance mean?

Traits are influenced by many genes, not just one (not monogenic).

What is the role of environment in development?

Environment interacts with genes to shape behavior and traits.

What does the PKU example show?

A single gene can cause intellectual disability, but environmental intervention (diet) can prevent it.

What does heritability measure?

The proportion of variation in a trait within a population due to genetic differences.

Does high heritability mean a trait is unchangeable?

No—high heritability does not imply immutability. Environment still plays a role.

What does greater environmental variability do to heritability?

It lowers heritability estimates.

Why study heritability?

To understand trait development, environmental influence, and population differences.

What is quantitative genetic research?

Studies naturally occurring genetic and environmental variation, often using twin studies.

What is molecular genetic research?

Focuses on specific gene mutations and their influence on behavior.

How do twin studies help understand heritability?

By comparing trait similarity between monozygotic (identical) and dizygotic (fraternal) twins.

What is gene–environment interaction?

The effect of genes depends on the environment, and vice versa.

What is gene–environment correlation?

A: Genetic influence on the environment a person experiences.

• Passive: inherited environment from parents

• Evocative: traits evoke responses from others

• Active: individuals choose environments that match their tra

What is methylation?

A process that silences gene expression—key in epigenetics.

What are the main parts of a neuron?

Cell body, dendrites, and axon.

What do glial cells do?

Help conduct electrical signals between neurons.

What are the four lobes of the cerebral cortex?

• Occipital (vision)

• Temporal (hearing, memory)

• Parietal (touch, spatial)

• Frontal (planning, reasoning)

What are key processes in brain development?

• Neurogenesis: creation of neurons

• Synaptogenesis: forming connections

• Myelination: insulating axons

• Synaptic pruning: removing unused connections

What is brain plasticity?

The brain’s ability to change and adapt based on experience.

What is experience-expectant plasticity?

The brain expects typical input (e.g., light, sound) to develop normally.

What is experience-dependent plasticity?

Brain development based on individual experiences and learning.

What are secular trends in development?

Changes in physical traits (e.g., height) across generations due to environmental factors.

What influences infant feeding?

SES, education, and food availability. Breast milk offers many health benefits.

What shapes food preferences in children?

• Evolutionary factors

• Prenatal environment

• Genetics

• Associative learning (e.g., branding with cartoons)

What are the effects of undernutrition?

it negatively impacts all areas of development—physical, cognitive, and emotional.