Biology and Behavior

Question 1

Model of Interaction

Answer 1

Three Key Elements:
Genotype - the genetic material an
individual inherits.
Phenotype - the observable expression of
the genotype, including both body
characteristics and behavior
Environment - every aspect of an
individual and his or her surroundings
other than genes

Question 2

5 Fundamental Relations in the Development
of Every Child

Answer 2

1. Parents’ genetic contribution to children’s
   genotypes
2. The contribution of children’s genotypes to their
   own phenotypes
3. The contribution of children’s environments to
   their phenotypes
4. The influence of children’s phenotypes on their
   environments
5. The influence of children’s environments on their
   genotypes

Question 3

Relation 1:
Parents’ Child’s
Genotype → Genotype

Answer 3

Genetic material is passed
on as chromosomes
-
carry biochemical
instructions involved in the
formation and functioning
of an organism
Genes: sections of
chromosomes that are the
basic units of heredity for all
living things

Question 4

Genetic Diversity

Answer 4

Mutations: changes in sections of DNA caused
by random or environmental factors
Random assortment: the shuffling of the 23
pairs of chromosomes in the sperm and egg;
chance determines which member of the pair
goes into the new sperm and egg
Crossing over: the process by which sections of
DNA switch from one chromosome to another
during meiosis.

Question 5

Relation 2:
Child’s Genotype → Child’s Phenotype

Answer 5

Only someof the genes that the child inherits are
expressed (at all, or at particular times in
development)
Regulator gene defects
-
thalidomide
-
visual/hearing experience

Question 6

Gene Expression

Answer 6

Allele: Different forms of human genes (most have 2 or more)
Most traits are governed by more than one gene
Most that are of interest to behavioral
scientists (shyness, aggression, empathy, etc.)
Also, many diseases and disorders (cancer,
Austism, etc.)

Question 7

Relation 3:
Child’s Environment → Child’s Phenotype

Answer 7

Observable characteristics (phenotype) result
from the interactionof environmental factors
AND the child’s genetic makeup (genotype)

Question 8

Genotype-Environment
Interaction

Answer 8

MAOA: x-linked gene
known to inhibit brain
chemicals associated
with aggression
If MAOA was inactive,
men who were
maltreated as children
were more likely to
engage in antisocial
behavior than those not
maltreated

Question 9

Relation 4:
Child’s Phenotype → Child’s Environment

Answer 9

Active Child
Children create their own environment
They evoke responses from others
They select their surroundings and experiences

Question 10

Relation 5:
Child’s Environment → Child’s Genotype

Answer 10

Although the structure of DNA remains “fixed”
(mutations aside), certain epigenetic
mechanisms can alter functioning of genes.
See methylation: epigenetic mechanism that
silences gene expression
Rat studies
Child studies/early-life stress

Question 11

Behavior genetics

Answer 11

The science concerned
with how variation in
behavior and development
results from the
combination of genetic and
environmental factors

Question 12

Heritable

Answer 12

Characteristics or traits
influenced by heredity
A statistical estimate of the degree of
variation in a phenotypic trait in a
population that is due to genetic variation
between individuals in that population.
-Heritability estimates range from 0 to 1 and
are often expressed as a percentage
-A number close to 1 may be indicative of a
highly heritable trait within a population

Question 13

Heritability estimate

Answer 13

Applies to a particular population living in a
particular environment
Reflects the environments of the populations of
individuals from which they are derived
Can change as a function of developmental factors,
even for the same trait in the same population
Studies of heritability to date:
Are limited because largely from samples of WEIRD
(White, Educated, Industrialized, Rich, and
Democratic) participants
High heritability does not imply immutability

Question 14

Individual Differences: Genetically
Transmitted Developmental Disorders

Answer 14

These conditions follow various inheritance
patterns and they have been studied using
both quantitative and molecular genetics
methodology.
Dominant-recessive patterns
Sex-linked-inheritance
Polygenic inheritance
Chromosomal anomalies
Genetic anomalies
Unidentified genetic basis

Question 15

The Importance of Experience

Answer 15

Experience plays a central role in determining which
of the brain’s excess synapses will be pruned and
which will be maintained.
Plasticityis the capacity of the brain to be affected by experience.

Question 16

Experience-Expectant
Processes

Answer 16

Experience-expectant plasticity is the process through
which the typical wiring of the brain occurs in part as a
result of the kinds of general experiences that every
human in a typical environment will have.
*If the expected experience is
not available, as in the case of
congenital cataracts,
development will be impaired.