Genes, environment, and development (ch 3)

Question 1

Species heredity

Answer 1

• genetic endowment that members of a species have in common including genes that influence maturation and aging processes
• Reason that certain patterns of development and aging are universal

Question 2

Darwin – three arguments

Answer 2

• Genetic variation in species otherwise no way for genetic makeup to change over time
• Some genes aid adaptation more than others do
• Genes that aid their bearers in adapting to their environment will be passed to future generations more frequently than genes that do not

Question 3

Natural selection

Answer 3

nature selects those members of species whose genes permit them to adapt to their environment

Question 4

Conception

Answer 4

new cell nucleus formed from general material of ovum and genetic material of sperm

Question 5

Zygote

Answer 5

new cell

Question 6

How many chromosomes does each parent contribute?

Answer 6

Each parent contributes 23 chromosomes

• 46 total
• organized into 23 pairs

Question 7

Chromosomes

Answer 7

threadlike bodies in nucleus of each cell made up of genes

Question 8

Sperm and ova each have only 23 chromosomes because produced through the …

Answer 8

cell division process of meiosis

Question 9

Single cell zygote becomes multiple-cell organism through the …

Answer 9

process of mitosis

Question 10

Human Genome Project

Answer 10

• Researchers mapped sequence of chemical units (A, C, G, T) that make up strands of DNA in full set of human chromosomes
• Human genome consists of genes that serve as template for the production of particular proteins and DNA that regulates the activity of the protein-producing genes
• 999 of 1000 base chemicals are identical; only 1 of 1000 accounts for human differences

Question 11

Father determines child’s sex

Answer 11

• If sperm carries Y chromosome, the XY zygote is genetic male
• If sperm carries X chromosome, the XX zygote is a genetic female

Question 12

Genotype:

Answer 12

Genetic makeup a person inherits

Question 13

Phenotype:

Answer 13

characteristics or traits that are expressed

Question 14

Gene expression:

Answer 14

activation of particular genes in particular cells at particular times

Question 15

Sex-linked characteristics

Influenced by

Answer 15

• single genes located on sex chromosomes
• Actually X-linked because most attributes are associated with genes on the X
• Y chromosomes are smaller and have fewer genes to serve as counterpart to dominate

Question 16

Single gene-pair inheritance:

Answer 16

• each of thousands of human characteristics influenced by only one pair of genes – one from mother and one from father
• Dominant gene will be expressed with paired with recessive gene (weaker gene that can be dominated)

Question 17

Polygenetic:

Answer 17

• traits such as height, weight, intelligence, personality, and susceptibility to cancer and depression
• Influenced by multiple pairs of genes and interactions with environment
• Many degrees of expression possible with polygenetic traits
• Traits tend to be distributed in the population according to normal curve

Question 18

Mutations:

Answer 18

change in gene structure or arrangement that produces a new phenotype

• Beneficial or harmful
• Eg sickle cell disease

Question 19

Chromosomal abnormalities:

Answer 19

occur when there are errors in the chromosome division during meiosis

• Ovum or sperm will have too many or too few chromosomes
• Main source of pregnancy loss

Question 20

Turner syndrome

Answer 20

Chrom. abnormality

• female born with single X chromosome (XO)
• Physically small, stubby fingers and toes, “webbed” neck, underdeveloped breasts

Question 21

Down syndrome

Answer 21

Chrom abnormality

• aka trisomy 21 because associated with three rather than two 21st chromosomes
• Distinctive eyelid folds, short stubby limbs, thick tongues, typically MR

Question 22

Klinefelter syndrome

Answer 22

Chrom. abnormality

• male born with one or more extra X chromosome (XXY)
• Tall, generally masculine but sterile and at puberty develop feminine sex characteristics like enlarged breasts; many below average intelligence

Question 23

Fragile X

Answer 23

Chrom. abnormality
- X chromosome barely connected and looks like it is about it break off
Most common hereditary cause of mental retardation

Question 24

Findings from behavioral genetics research – IQ

Answer 24

• Correlation highest in identical twins
• Heritability of IQ is about .50
• Genetic differences account for 50 percent of variation in IQ and environmental differences for 50 percent

Question 25

Temperament:

Answer 25

tendencies to respond in predictable ways that serve as the building blocs of personality

Question 26

Concordance rate for Sz

Answer 26

• in identical twin pairs is 48 percent and for fraternal twins 17 percent
• 90 percent of children who have one parent with schizophrenia do not develop schizophrenia
• This means that environmental factors contribute significantly
• People inherit predispositions to develop disorders, not the disorder per se

Question 27

Traits that are strongly inheritable include:

Answer 27

1. Physical characteristics – eye color, height, weight
2. Physiological functions – measured brain activity, reactions to alcohol, level of physical activity, susceptibility to certain diseases

Question 28

Trait that is moderately inheritable:

Answer 28

General intelligence

Question 29

Traits that are less heritable:

Answer 29

Aspects of temperament and personality, susceptibility to many psychological disorders