Genetics and Organism Development Quiz

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Questions and Answers

What role do genes play in the development of an organism?

Genes directly determine behaviour and traits.

Genes create biochemical differences that influence development probabilistically. (correct)

Genes have no impact on environmental interactions during development.

Genes are responsible for forming chromosomes only.

How many pairs of chromosomes do humans typically have?

24 pairs

23 pairs (correct)

22 pairs

20 pairs

What is the relationship between a child's genotype and their phenotype?

The child's genotype contributes to the development of their phenotype. (correct)

The child's environment overrides the influence of their genotype.

The child's phenotype is strictly inherited from parents.

The child's genotype has no influence on their phenotype.

Which statement accurately describes chromosomes?

Chromosomes are long, threadlike molecules made up of DNA. Signup and view all the answers

What is the influence of a child's phenotype on their environment?

The phenotype can create environmental conditions that modify development. Signup and view all the answers

What is a consequence of maternal alcoholism during pregnancy?

Fetal alcohol syndrome Signup and view all the answers

Which environmental factor is associated with low birth weight and retarded growth?

Cigarette smoking Signup and view all the answers

Which of the following is a recommended practice to reduce the risk of SIDS?

Use firm mattresses for bedding Signup and view all the answers

What state of arousal is characterized by the absence of motor activity and regular brain waves?

Quiet sleep Signup and view all the answers

What role does brain activity during REM sleep play according to autostimulation theory?

It compensates for deprivation of external stimuli. Signup and view all the answers

How does crying evolve during early infancy?

It becomes a more effective means of communication. Signup and view all the answers

What percentage of a newborn's total sleep time is made up of REM sleep?

50% Signup and view all the answers

What is one effective soothing technique for a crying infant?

Swaddling the baby in cloth. Signup and view all the answers

How does REM sleep in newborns compare to that of young adults?

Newborns have more REM sleep Signup and view all the answers

Which of the following is NOT considered a state of arousal in newborns?

Gentle transition Signup and view all the answers

What characterizes resilient children according to developmental resilience?

They often receive responsive care from caregivers. Signup and view all the answers

What is the typical sleep pattern of newborns compared to young adults?

Newborns sleep more than young adults Signup and view all the answers

What is the genotype in the model of interaction?

The genetic material inherited from parents. Signup and view all the answers

How do heredity and environment contribute to individual characteristics?

They interact to shape various traits. Signup and view all the answers

What is a common risk factor in developmental outcomes?

Multiple associated negative factors. Signup and view all the answers

What percentage of genetic difference exists between individuals?

Less than 1.5% Signup and view all the answers

Which chromosome is associated with a higher likelihood of inherited disorders in males due to recessive alleles?

X chromosome Signup and view all the answers

What is the primary focus of behavioral genetics?

The impact of environmental factors on genetic traits Signup and view all the answers

What effect does the 2R variant of the MAOA gene have on behavior?

It increases the likelihood of committing serious crimes Signup and view all the answers

How does high activity of the MAO-A gene influence the effects of maltreatment?

It reduces the impact of abuse on future criminal behavior Signup and view all the answers

What does behavioral geneticists' belief about traits being multifactorial imply?

They result from a combination of both genetic and environmental influences Signup and view all the answers

Which disorder is associated with a single dominant gene inheritance pattern?

Huntington’s disease Signup and view all the answers

What is the chromosomal composition of a male at birth?

XY Signup and view all the answers

What is a common characteristic of recessive genetic disorders?

Both alleles must be present for the disorder to manifest. Signup and view all the answers

Which of the following conditions is a result of errors in meiosis?

Down syndrome Signup and view all the answers

Which statement accurately describes the relationship between sickle-cell anemia and malaria?

Sickle-cell carriers have both disease and health benefits from the disorder. Signup and view all the answers

What is the process through which the embryo's unspecialized stem cells become different types of cells?

Cell differentiation Signup and view all the answers

What develops from the inner cell mass in a blastocyst?

Embryo Signup and view all the answers

How do identical twins originate during early development?

From splitting of the inner cell mass Signup and view all the answers

What does the placental membrane primarily protect against?

Some toxins and infectious agents Signup and view all the answers

Which prenatal process enables the migration of cells to their destination in the embryo?

Cell migration Signup and view all the answers

At what stage does the fetus begin to habituate to repeated stimuli?

32 weeks Signup and view all the answers

What factor significantly influences the effects of teratogens during prenatal development?

Timing of exposure Signup and view all the answers

Which of the following accurately describes experience-expectant plasticity?

Depends on common experiences in a normal environment Signup and view all the answers

What is described as the movement of materials between the mother's bloodstream and that of the fetus?

Placental transfer Signup and view all the answers

What term refers to the selective death of certain cells during prenatal development?

Apoptosis Signup and view all the answers

What is one of the earliest forms of sensory experience for the fetus?

Taste and smell from amniotic fluid Signup and view all the answers

What is characteristic of the cephalocaudal pattern of development?

Regions near the head develop earlier Signup and view all the answers

What is one outcome if an expected experience is not provided during sensitive periods?

Development may be impaired Signup and view all the answers

Study Notes

Prenatal Development Overview

Prenatal development encompasses the period from conception to birth, involving biological and behavioural factors.
The lecture covers various stages, including conception, early development, fetal behaviour, experience, and learning. It also examines hazards to prenatal development.
It includes a historical perspective, highlighting shifts in understanding developmental processes.
Recent research techniques and advances in genetics have revolutionized the study of embryology and prenatal development.

Conception

Prenatal development begins with conception, the union of egg and sperm (gametes).
Gametes are formed through meiosis, a specialized cell division that results in gametes containing half the genetic material of normal body cells.
Sex differences arise at conception with approximately 120-150 male conceptions for every 100 female conceptions. The Y chromosome bearing sperm are lighter and swim faster than those bearing an X chromosome.

The Zygote

The fertilized egg, or zygote, has a complete set of human genetic material (half from each parent).
The zygote marks the start of three prenatal development periods: germinal, embryonic, and fetal.
The three periods describe the significant phases of development from conception to birth.

Periods of Prenatal Development

Germinal Period (0-2 weeks): Rapid cell division happens after conception, leading to implantation in the uterine wall.
Embryonic Period (3-8 weeks): Major development in organs and systems occurs through cell division, migration, differentiation, and cell death, alongside hormonal influences.
Fetal Period (9 weeks - birth): Continued physical structure development, rapid growth of the body, increasing behavioural and sensory experiences, and learning.

The Cells

Prenatal development involves four key processes: cell division leading to proliferation, cell migration, cell differentiation, and apoptosis (programmed cell death).
These actions contribute to the transformation of the zygote to a fetus.
Cell differentiation results in the formation of over 350 different cell types in the embryo.

The Role of Hormones

Hormones, particularly testosterone, play a crucial role in sexual differentiation.
Human fetuses initially have the potential for both male and female genitalia that develop depending on the presence or absence of testosterone.
Fetal development encompasses various processes, not just the development of physical traits, but also the influence on their own environment and behaviour development.

The Blastocyst

By the fourth day after conception, the zygote transforms into a blastocyst, a hollow sphere of cells with an inner cell mass (ICM) on one side.
The inner cell mass eventually forms the embryo.

Identical vs. Fraternal Twins

Identical twins arise from the splitting of the inner cell mass, resulting in genetically identical individuals (100%).
Fraternal twins result from two eggs being released and fertilized by different sperm, leading to siblings who are genetically similar (50%).

The Embryo

After implantation, the ICM develops into the embryo and associated support systems like the neural tube.
The neural tube, formed from differentiated cells, eventually becomes the brain and spinal cord.
The developing embryo relies on a support system—the placenta and umbilical cord.

Protecting the Fetus

The placental membrane shields the fetus from some toxins and infectious agents.
The amniotic sac, filled with fluid, provides a protective cushion for the fetus.

Fetus Development Stages

Images of fetuses at various stages of development (e.g., 4, 9, 11, 16, 18, 20, 28 weeks) are presented. Note each stage represents a specific point of development.

Fetus Learning

The fetus exhibits learning capabilities, such as decreased responses to repeated stimulation (habituation).
Newborns demonstrate the ability to recognise rhymes and stories heard prenatally, indicating fetal learning influences postnatal abilities.

Sensitive Periods

Sensitive periods in early brain development correlate with specific times in development, and are indicative of periods where the brain is most receptive to new types of input.

Experience-Expectant vs. Experience Dependent Plasticity

Experience-expectant plasticity describes consistent early development resulting from experiences common to all (or most) individuals.
Experience-dependent plasticity refers to neural changes that result from specific individual experiences.

Teratogens

Teratogens are environmental agents capable of causing harm during prenatal development, and timing of exposure is crucial for understanding the effects.
Timing is crucial; damage depends on the phase of development a teratogen is encountered.
Examples include alcohol, drugs (e.g., cocaine, heroin), maternal illnesses, and environmental pollutants.

Some Environmental Hazards

This includes various drugs and maternal diseases.
Teratogens, including substances like mercury and PCBs, are harmful to a developing fetus.
Teratogens can lead to various negative outcomes, including birth defects, developmental delays, and mental retardation

Maternal Alcoholism

Maternal alcoholism can cause Fetal Alcohol Syndrome (FAS), characterized by mental retardation, facial deformities, and other health issues.

Cigarette Smoking

Cigarette smoking during pregnancy can result in retarded growth and low birth weight.
Smoking is associated with increased risk of sudden infant death syndrome (SIDS).
Risk factors to consider are exposure time and amount of a teratogen.

The Newborn Infant

The newborn infant exhibits particular states of arousal.
Physiological indicators of arousal include measurable states of sleep (e.g., active, quiet) and alertness (e.g., active awake, alert awake, drowsing).
Significant variations in amount of each state of sleep and alertness are possible.

Interacting With The Environment

A newborn's state of arousal and engagement level influence their exploration of the environment.
Experience of the environment and states of arousal relate strongly to an infant's interaction with the environment.

Six States of Arousal

A newborn's state of arousal represents different stages of activity and alertness.

Newborn States

A pie chart illustrates the approximate time spent in each state of arousal.

Sleep

REM (rapid eye movement) sleep constitutes the major portion of sleep during early development.
Non-REM sleeps occur during early developmental periods and represents significant periods of development.
Autostimulation theory discusses the important role of REM sleep in fetal and newborn development and how it facilitates the development of the visual system.

Crying

Crying in infants initially reflects discomfort or frustration, but with experience, parents improve at interpreting its meaning.
Parents develop techniques to soothe infants.
There are multiple factors that influence a newborn's development, which requires the understanding of parents to develop effective techniques.

Risk Factors

Negative outcomes are more likely when several risk factors are present.

Developmental Resilience

Resilience to negative factors involves successful developmental outcomes despite risks. Children with responsive care and specific characteristics like intelligence or responsiveness to others often develop resilience.

Genetic and Environmental Forces

Heredity and environment interact in complex ways to influence characteristics.
Behavioural geneticists investigate how genes and environment interact, focusing on multifactorial traits.

Model of Interaction

Genotype (genetic makeup) and environment interact to produce phenotype (observable characteristics).

Fundamental Relations

Parents' genetic make-up contributes to the child's genotype.
The child's genotype influences their phenotype (observable characteristics).
The child's environment impacts the development of their phenotype.

Genetics

Genetic material (chromosomes made of DNA) carries instructions for all biochemical processes.
Genes are the units of heredity but don't directly code for traits.
Traits result from cellular processes involving interaction between genes and environment.

Alleles

Many genes have different forms called alleles.
Dominant alleles are expressed if present.
Recessive alleles are expressed only if both alleles are recessive.
Homozygous individuals have matching alleles, while heterozygous individuals have different alleles for a gene.

Genes Work Together

Traits often involve multiple genes (polygenic inheritance).
Some genes influence multiple traits (pleiotropy).
Examples like Phenylketonuria (PKU) highlight how genes and environment interact to influence development.

Genetic Origins of Human Diseases

Many diseases and disorders result from genetic factors.
Disorders can be associated with recessive genes, single genes, sex-linked inheritance, or errors in meiosis.

Dominant vs. Recessive Inheritance

Illustrations demonstrate how dominant and recessive traits are passed down through generations.

Genetic Origins of Human Diseases and Disorders

Some genes have both positive and negative effects (e.g., sickle-cell anemia, protecting against malaria).
Genetic basis of certain syndromes like dyslexia and Tourette's is not always fully understood.

Sex Chromosomes

The 23rd pair of chromosomes determines biological sex (XX for females; XY for males).
The Y chromosome carries genes crucial for triggering male sexual development.
The Y chromosome, containing significantly fewer genes, can be vulnerable to harmful recessive traits compared to the X chromosome.

The Male Disadvantage

The Y chromosome, having fewer genes than the X, means males are often more susceptible to certain kinds of disorders.
Inherited disorders caused by recessive alleles on the X-chromosome result in a vulnerability for males.

Behavioral Genetics

Behavioural genetics studies how environmental and genetic factors influence behaviour.

The Case of MAO-A

MAOA gene activity influences aggression differently based on environmental exposure during early childhood.
Individuals' genes can predispose them, but environment plays a crucial role in how that affects developmental pathways of the individual.

Children's Own Behaviour

Children actively shape their environment, evoking reactions in others and selecting experiences.
Their behaviour influences their environment.
Experience varies by individual, and individuals' experiences also vary by their environment, which can influence how they develop.

The Family Study

Family studies investigate trait correlations among genetically related individuals.
Comparisons are conducted between genetically related individuals versus genetically unrelated individuals to assess the role of similar environments.

Types of Family Studies

Twin-study designs compare monozygotic (identical) and dizygotic (fraternal) twins.
Adoption studies investigate correlations between adopted children and their biological and adoptive relatives.

Minnesota Study of Twins Reared Apart

This study highlights the significant role of genetic factors in traits like IQ.
Environmental factors influence development, particularly in shaping behaviours relevant to stressors or situations of interest to individuals/environment.

Average Familial IQ Correlations

Measures the correlation between IQ scores in different family relationships (biological twins, siblings, etc.); this is also relevant to studies of hereditary versus environment.

Heritability

Heritability estimates the proportion of trait variation in a population due to genetic factors.
Heritability is a population-level estimate and does not explain individual behaviours.
Heritability estimates need to be contextualized within the environment.

Shared vs. Nonshared Factors

Shared environmental factors influence siblings similarly.
Nonshared environmental factors produce unique experiences among siblings, impacting development differently based on specific experiences.

Next Week

The next lecture will cover physical and cognitive development in infancy and toddlerhood.

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Description

Test your knowledge on the fundamental concepts of genetics and their roles in organism development. Explore key ideas such as chromosomes, genotypes, phenotypes, and their interactions with the environment. Perfect for students studying biology or related subjects.