Introduction to Behavior Genetics

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Questions and Answers

What do twin studies primarily investigate in the context of behavior genetics?

The effects of environmental influences on behavior

The role of upbringing in shaping personality traits

The inheritance of behavioral tendencies in identical twins (correct)

The similarities between fraternal twins raised apart

What key finding is associated with adoption studies related to behavior genetics?

Adopted children resemble their biological parents more than their adoptive parents (correct)

Adoptive parents always influence behavioral tendencies over genetics

Adoptive children fully mirror the behavior of their adoptive parents

Genetics have no bearing on adopted children's future behavior

What conclusion can be drawn from selective breeding in animals according to behavior genetics?

All behavioral traits are determined solely by selective breeding practices

If a trait does not change through breeding, it is likely environmentally based (correct)

Selective breeding can completely change an animal's innate behaviors

Behavioral traits cannot be influenced by genetics

How do identical twins differ from fraternal twins in behavior studies?

Identical twins provide insights into genetics since they share the same genes Signup and view all the answers

In behavior genetics, what role does heredity play in behavioral characteristics according to selective breeding?

Heredity influences traits which can be altered through selective breeding Signup and view all the answers

What primarily influences human development according to psychologists?

Heredity and environment Signup and view all the answers

What is the term for the transmission of traits from parents to offspring?

Heredity Signup and view all the answers

What structure contains the genes that transmit genetic characteristics in a cell?

Nucleus Signup and view all the answers

How many pairs of chromosomes do humans have?

23 pairs Signup and view all the answers

What is the role of behavior genetics?

To analyze the inheritance of behavioral tendencies Signup and view all the answers

Which chromosome pair contains the sex-linked genes?

Pair no. 23 Signup and view all the answers

What determines the physical traits an individual may inherit?

The genetic makeup inherited from parents Signup and view all the answers

What comprises the zygote formed during fertilization?

Sperm cell and egg cell Signup and view all the answers

What is the primary focus of studies on identical twins?

Similarities in physical characteristics and behavior Signup and view all the answers

What effect do adoption studies reveal regarding biological traits?

Adopted children resemble their biological parents more than adoptive parents Signup and view all the answers

Which characteristic is associated with phenylketonuria (PKU)?

It requires a special diet to manage amino acid breakdown Signup and view all the answers

What type of twins develop from two separate zygotes?

Fraternal twins Signup and view all the answers

Which disorder is caused by the abnormal shape of red blood cells?

Sickle-cell anemia Signup and view all the answers

What is the role of selective breeding in behavioral genetics?

To demonstrate the impact of heredity on traits Signup and view all the answers

What is the gestation period duration in humans?

9 months Signup and view all the answers

During which stage does the embryo begin to develop recognizable features?

Period of the embryo Signup and view all the answers

Which syndrome results from an extra chromosome in the 21st pair?

Down syndrome Signup and view all the answers

What technique is used to detect fetal problems through chromosomal abnormalities?

Amniocentesis Signup and view all the answers

What is a common trait of individuals with Klinefelter syndrome?

Underdeveloped testes and female-like breasts Signup and view all the answers

Which genetic disorder is most commonly found among people of Eastern European Jewish ancestry?

Tay-Sachs disease Signup and view all the answers

What are the two main components of the prenatal stage?

Zygote and fetal periods Signup and view all the answers

What occurs during the period of the fetus in human development?

Significant growth and function of organs Signup and view all the answers

What is a primary characteristic of the infancy stage in postnatal development?

The infant relies heavily on others for survival. Signup and view all the answers

Which developmental stage is characterized by rapid physical growth and a decrease in helplessness?

Babyhood Signup and view all the answers

What is a notable behavior of children in the early childhood stage?

They become curious and ask numerous questions. Signup and view all the answers

What period is referred to as the 'gang age' in postnatal development?

Late Childhood Signup and view all the answers

What significant changes occur during puberty?

Activation of gonads and production of sex hormones. Signup and view all the answers

Which stage is associated with emotional instability and identity crisis?

Adolescence Signup and view all the answers

What does early adulthood typically involve in terms of adjustments?

Adjustments to work, marriage, and parenthood. Signup and view all the answers

What is said about the middle adulthood stage in terms of success?

It is often the peak period for authority and prestige. Signup and view all the answers

What characterizes the late adulthood stage?

Physical and mental deterioration begins. Signup and view all the answers

Study Notes

Behavior Genetics

Behavior genetics combines genetics and psychology to study how behavioral tendencies are inherited.
Researchers use various methods to understand the link between genes and behavior, including twin studies, adoption studies, and selective breeding.
Behavior is a product of the interaction of genetic endowments and environmental conditions.
Heredity provides innate capabilities and potentials that can be developed by environmental factors.
Genes determine physical traits (hair color, eye color, body form), emotions, and motivations; environment can influence the expression of these inherited traits.
Genes do not determine the potential to experience a new emotion.

Twin Studies

Identical twins (same genes) show similar physical traits and behaviors even when raised apart.
Fraternal twins (different genes) may not share the same physical traits or behaviors, even if raised together.
Studies on identical twins, even separated at birth, reveal similar physical characteristics and behavioral tendencies.

Adoption Studies

Adopted children often resemble their biological parents more than their adoptive parents.
Children with alcoholic biological parents are at increased risk for alcoholism, even if raised by non-alcoholic adoptive parents.
Studies show adopted children tend to resemble biological parents more than adoptive ones.

Selective Breeding

Selective breeding in animals is used to study the inheritance of traits.
Dogs have been selectively bred for traits like excitability and lethargy.
If a trait can be changed through selective breeding, it suggests a hereditary influence.
If a trait is not affected by selective breeding, it implies a stronger environmental impact.

Prenatal Stage

The prenatal stage (gestation period) lasts 9 months or 280 days between conception and birth.
Divided into the germinal period (zygote), embryonic period, and fetal period.
Zygote period starts at conception until the second week.
Embryonic stage runs from the second week to the third month, and primitive organ development occurs. By week 8, arms, legs, and a discernible face are present.
Fetal stage covers months three through nine; rapid growth and development occur. At 16-18 weeks, mother may feel fetal movement; hair grows; facial features become recognizable; major organs begin functioning, but the fetus could not yet survive outside the womb.

Genetic Influences on the Fetus

Some abnormal traits have hereditary bases, including:
- Phenylketonuria (PKU): An inherited form of mental retardation due to a disorder of amino-acid metabolism. Treatable if diagnosed early.
- Sickle-cell anemia: Disorder of red blood cell shape; frequently affects African Americans; death during childhood is possible.
- Tay-Sachs disease: Disorder in fat breakdown; most often affects Eastern European Jews; death typically by age 3 or 4.

Other Genetic Abnormalities

Down syndrome: Extra chromosome on the 21st pair (47 chromosomes instead of 46). Characteristics include a round face and slanted eyes; mental retardation is common but individuals are typically friendly and cheerful. Also known as mongolism.
Turner's syndrome: Loss of one X chromosome in females (45 chromosomes). Underdeveloped ovaries; infertility and often associated with mental retardation.
Klinefelter syndrome: Extra X chromosome in males (47 chromosomes). Underdeveloped testes; female-like breast development; mental retardation can be present.
XYY syndrome: Extra Y chromosome in males (47 chromosomes). Increased height; sometimes associated with aggressive and violent tendencies.

Techniques to Diagnose Fetal Problems

Amniocentesis: Needle inserted through the abdomen to sample amniotic fluid. Provides information about the child's sex and some chromosomal abnormalities. Done from week 15 onwards.
Fetoscopy: Tiny instrument inserted into the amniotic cavity to view the fetus. Useful for identifying hand and leg defects; performed after week 16.
Ultrasound: Uses waves to create images, allowing physicians to detect structural abnormalities. Useful pictures can be obtained as early as week 7.

Postnatal Development

Infancy: First two weeks after birth; major adjustment period.
Babyhood: Second week to second year; rapid growth, increased independence, development of sitting, standing, crawling, walking, and speaking.
Early Childhood: Second year to sixth year; questioning stage, curiosity, temper tantrums, emotional outbursts; preschool age.
Late Childhood: Sixth year to puberty; gang age, socialization, formal schooling, "smart age"; a period of self-assured confidence expressed through verbal information.
Puberty: Overlaps late childhood and adolescence; physical changes due to gonadal activation and sex hormone production.
Adolescence: After puberty to age 18; emotional instability, identity crisis, aggressiveness, awkwardness, curiosity about sex, but eventual emotional stability and social responsibility.
Early Adulthood: 18 to approximately 40 years; adjustments to work, marriage, and parenthood.
Middle Adulthood: 40 to 60 years; peak period for financial and social success; authority and prestige; stage of life that reflects how happy or unhappy one becomes as an adult;
Late Adulthood: 60 years and above; physical and mental deterioration may be part of the aging process, along with the cessation of reproductive capabilities.

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Description

This quiz explores the fundamentals of behavior genetics, focusing on how genetics and psychology intersect to influence behavior. Topics include twin and adoption studies, as well as the role of selective breeding in understanding inheritance of traits.