Chapter 3 Summary - PDF

8/30/24, 12:16 PM Chapter 3: Summary Chapter 3: Summary --- # Biological Foundations, Genetics, Prenatal Development, and Birth: Comprehensive Summary Chapter 3 covers the biological f...

8/30/24, 12:16 PM Chapter 3: Summary Chapter 3: Summary --- # Biological Foundations, Genetics, Prenatal Development, and Birth: Comprehensive Summary Chapter 3 covers the biological foundations of development, focusing on genetics, prenatal development, and the birth process. The chapter explores how genetic information is transmitted from parents to children, the role of inheritance in development, and how genetic abnormalities can affect a child. It also discusses the stages of prenatal development and the risks associated with pregnancy and childbirth. --- ## Conclusion The chapter emphasizes the significance of understanding the biological and genetic factors that influence development. It underscores the interplay between heredity and environment, highlighting that both are crucial in shaping an individual's growth and development. By understanding genetic transmission, prenatal development, and the birth process, parents and healthcare professionals can better manage potential risks and support healthy development from conception through birth. --- ## Key Points Genetic Transmission: Genetic information is passed from parents to children through gametes, with each parent contributing 23 chromosomes to the zygote. Role of DNA: DNA, the molecule that contains genetic information, directs the development of all cells in the body. It replicates during cell division, ensuring that genetic material is passed to all cells. Inheritance Patterns: Traits are inherited through dominant and recessive genes, with some characteristics being influenced by multiple genes (polygenic inheritance). Genetic Abnormalities: Abnormalities can occur due to extra or missing chromosomes or defective genes, leading to conditions like Down syndrome or cystic fibrosis. Genetic Counselling: Genetic counselling helps couples understand the risks of genetic disorders and make informed decisions about conception and prenatal care. Prenatal Development Stages: Prenatal development is divided into three stages: germinal (first two weeks), embryonic (weeks 3-8), and fetal (week 9 to birth). Risks During Pregnancy: Various risks, including genetic disorders, environmental factors, and maternal health, can affect prenatal development. Birth Process: The chapter describes the stages of labour and delivery, potential complications, and medical interventions used to ensure a safe birth. Cultural Sensitivity: The chapter also touches on the importance of cultural sensitivity in genetic counselling and prenatal care, particularly in Indigenous communities. Research Methods: Adoption and twin studies are used to explore the relative influence of genetics and environment on development. --- ## Summary 1. Genetic Transmission: The chapter starts by explaining how genetic information is transmitted from parents to offspring through chromosomes contained in sperm and egg cells. 2. Role of DNA: DNA is the blueprint for all genetic information, responsible for directing the development of every cell in the body. 3. Patterns of Inheritance: Traits are inherited through specific patterns, including dominant-recessive and polygenic inheritance, with some traits being influenced by multiple genes. 4. Genetic Abnormalities: The chapter discusses various genetic disorders, how they occur, and their impact on development, including conditions like Down syndrome and cystic fibrosis. 5. Genetic Counselling: The importance of genetic counselling is highlighted, providing couples with the information they need to understand genetic risks and make informed decisions about pregnancy. 6. Stages of Prenatal Development: Prenatal development is divided into three stages: germinal, embryonic, and fetal, each marked by significant developmental milestones. 7. Risks During Pregnancy: The chapter outlines potential risks during pregnancy, including genetic abnormalities, maternal health https://loop.cloud.microsoft/print/eyJwIjp7InUiOiJodHRwczovL2VkaXRoY293YW51bmkuc2hhcmVwb2ludC5jb20vOmZsOi9yL2NvbnRlbnRzdG9y… 1/5 8/30/24, 12:16 PM Chapter 3: Summary issues, and environmental factors. 8. The Birth Process: Detailed descriptions of labour, delivery, and potential complications are provided, along with the medical interventions that can ensure a safe birth. 9. Cultural Sensitivity: Cultural differences in genetic counselling and prenatal care are discussed, emphasizing the need for sensitivity and understanding in diverse populations. 10. Research Methods: Adoption and twin studies are presented as key methods for understanding the relative influence of genetics and environment on development. Table: Key Concepts in Chapter 3 - Biological Foundations, Genetics, Prenatal Development, and Birth Concept Description Genetic Transmission Genetic information is passed from parents to offspring through 1 gametes, with each gamete contributing 23 chromosomes to the zygote. DNA's Role DNA contains the genetic code that directs the development and 2 function of all cells in the body, ensuring that genetic information is replicated during cell division. Inheritance Patterns Traits are inherited through dominant and recessive genes, with 3 some characteristics influenced by multiple genes (polygenic inheritance). Genetic Abnormalities Abnormalities in chromosome number or defective genes can lead 4 to genetic disorders such as Down syndrome, cystic fibrosis, and sickle-cell anaemia. Genetic Counselling Provides couples with information on genetic risks, helping them 5 make informed decisions regarding conception, prenatal care, and potential genetic disorders. Prenatal Development Stages Prenatal development occurs in three stages: germinal (first two 6 weeks), embryonic (weeks 3-8), and fatal (week 9 to birth), each crucial for proper development. Risks During Pregnancy Risks include genetic disorders, maternal health issues, and 7 environmental factors, which can impact the health of both mother and child during pregnancy. Birth Process The process includes labour, delivery, and potential complications, 8 with medical interventions available to ensure the safety of both mother and child. Cultural Sensitivity Emphasizes the importance of culturally sensitive genetic 9 counselling and prenatal care, particularly for diverse populations such as Indigenous communities. Research Methods Adoption and twin studies are key for understanding the influence 10 of genetics versus environment on development, providing insights into the nature vs. nurture debate. New SUMMARY 3.1 Explain the role of inheritance in development. Central to our understanding of how development proceeds is a knowledge of the genetic contribution to the emergence of skills and abilities, which ensures an understanding of the nature-versus-nurture debate. Research and new evidence provides information on how inheritance and environment interact in development. Genetic research indicates some of the most interesting scientific discoveries to https://loop.cloud.microsoft/print/eyJwIjp7InUiOiJodHRwczovL2VkaXRoY293YW51bmkuc2hhcmVwb2ludC5jb20vOmZsOi9yL2NvbnRlbnRzdG9y… 2/5 8/30/24, 12:16 PM Chapter 3: Summary date. Genetics plays a major role in behaviour, and some of the most recent critical discoveries have related to genetic disorders including Down syndrome, Alzheimer’s disease and bipolar disorder. Genetic information is contained in a complex molecule called deoxyribonucleic acid (DNA). Reproductive cells, or gametes, divide by a process called meiosis and recombine into a zygote at conception. Meiosis gives each gamete one-half of its normal number of chromosomes; conception brings the number of chromosomes to normal again and gives the new zygote an equal number of chromosomes from each parent. Other body cells produce new tissue through division of their genes, chromosomes and other cellular parts by means of a process called mitosis. 3.2 Describe how genetic differences are usually transmitted from one generation to the next. A person’s genotype is the specific pattern of genetic information inherited in their chromosomes and genes at conception. A person’s phenotype is the physical and behavioural traits the person actually shows during their life. Phenotype is the product of the interactions of genotype with environment. Although most genes exist in duplicate, some, called dominant genes, may actually influence the phenotype if only one member of the pair occurs. Recessive genes do not influence the phenotype unless both members of the pair occur in a particular form. Many traits are polygenic, meaning they are transmitted through the combined action of several genes. Sex is determined by one particular pair of chromosomes, called the X and Y chromosomes, and a testis-determining factor (TDF) incorporated on the SRY on a small section of the Y chromosome. 3.3 Understand how genetic abnormalities occur. Some genetic abnormalities, such as Down syndrome (trisomy 21), occur when an individual inherits too many or too few chromosomes. Others occur because particular genes are defective or abnormal even though the chromosomes are normal. Examples include Huntington’s disease, cystic fibrosis, and fragile X syndrome. 3.4 Consider the role of experts in helping parents discover and respond to potential genetic abnormalities. Genetic counselling can provide parents with information about how genetics influences the development of children and about the risks of transmitting genetic abnormalities from one generation to the next. Personal circumstances and cultural differences in beliefs and expectations must be considered in helping couples reach informed decisions about pregnancy. 3.5 Explain how heredity and environment jointly influence development. According to behavioural geneticists, every characteristic of an organism is the result of the unique interaction between the genetic inheritance of the organism and the sequence of environments through which it has passed during its development. The concept of range of reaction describes the strength of genetic influence under different environmental conditions. Studies of identical twins and of adopted children suggest that heredity and environment operate jointly to influence developmental change. Linkage and association studies use repeated DNA segments called polymorphisms as genetic markers to locate abnormal genes. Neither biogenetic nor environmental determinism is likely to give us adequate understanding of human development, which is the product of genes, environment and individual choice. 3.6 Discuss the important developmental changes that occur during prenatal development. Prenatal development begins with conception, in which a zygote is created by the union of a sperm cell from the father and an egg cell, or ovum, from the mother. It consists of discrete periods, or stages. The germinal stage occurs during the first two weeks following conception; the zygote forms a blastocyst, which differentiates into three distinct layers and then implants itself on the uterine wall to form the embryo. During the embryonic stage — weeks three through eight — the placenta and umbilical cord form and the basic organs and biological systems begin to develop. During the foetal stage — week nine until the end of pregnancy — all physical features complete their development. The experience of pregnancy includes dramatic changes in a woman’s physical functioning and appearance, as well as significant psychological changes as prospective parents anticipate the birth of the baby. Infertility is the inability to conceive or carry a pregnancy to term after one year of unprotected intercourse. Family planning allows people to decide on the number and spacing of their children. Methods of contraception, including hormones, condoms, intrauterine devices, periodic abstinence and withdrawal, allow families to voluntarily prevent unintended pregnancy. Abortion is used to terminate pregnancy. 3.7 Recognise the risks a mother and baby may face during pregnancy and the birth process, and how can they be minimised. Although prenatal development is highly canalised, there are critical periods — particularly during the first trimester — when embryonic development is highly vulnerable or at risk for disruptions from teratogens, substances or other environmental influences, that can damage an embryo’s growth. Teratogenic effects depend on the timing, intensity and duration of exposure, the presence of other risks, and the biological vulnerability of baby and mother. Risk factors for prenatal development include both medicinal and non-medicinal drugs, such as heroin, cocaine, alcohol and tobacco; diseases such as syphilis, gonorrhoea and HIV/AIDS; physical and biological characteristics of the mother; and physical, biological and chemical environmental hazards. Domestic violence also increases risks to prenatal and postnatal development, as well as developmental risks to the mother. Adequate prenatal nutrition and health care for the mother and her developing baby are associated with successful pregnancy, a normal birth and healthy neonatal development. 3.8 Describe what happens during the birth process, what difficulties may occur, and how they are handled. Labour occurs in three distinct but overlapping stages. The first stage, during which uterine contractions increase in strength and regularity and the cervix dilates sufficiently to accommodate the child’s head, takes from 8 to 24 hours (for a first-time mother). The second stage, when the dilation of the cervix is complete and the birth itself takes place, lasts from 60 to 90 minutes. The third stage, during which the placenta is delivered, lasts only a few minutes. Nonhospital birth centres and home births are two alternatives to hospital-based births. Prepared childbirth is now widely used in both hospital and non-hospital birth settings to help women actively and comfortably meet the challenges of giving birth. Many https://loop.cloud.microsoft/print/eyJwIjp7InUiOiJodHRwczovL2VkaXRoY293YW51bmkuc2hhcmVwb2ludC5jb20vOmZsOi9yL2NvbnRlbnRzdG9y… 3/5 8/30/24, 12:16 PM Chapter 3: Summary babies are now birthed by midwives, who provide care to women during pregnancy, childbirth and the weeks following birth. Doulas do not birth babies, but help the mother during labour and birth, and with her newborn. Although pain-reducing medications According to behavioural geneticists, every characteristic of an organism is the result of the unique interaction between the genetic inheritance of the organism and the sequence of environments through which it has passed during its development. The concept of range of reaction describes the strength of genetic influence under different environmental conditions. Studies of identical twins and of adopted children suggest that heredity and environment operate jointly to influence developmental change. Linkage and association studies use repeated DNA segments called polymorphisms as genetic markers to locate abnormal genes. Neither biogenetic nor environmental determinism is likely to give us adequate understanding of human development, which is the product of genes, environment and individual choice. 3.6 Discuss the important developmental changes that occur during prenatal development. Prenatal development begins with conception, in which a zygote is created by the union of a sperm cell from the father and an egg cell, or ovum, from the mother. It consists of discrete periods, or stages. The germinal stage occurs during the first two weeks following conception; the zygote forms a blastocyst, which differentiates into three distinct layers and then implants itself on the uterine wall to form the embryo. During the embryonic stage — weeks three through eight — the placenta and umbilical cord form and the basic organs and biological systems begin to develop. During the foetal stage — week nine until the end of pregnancy — all physical features complete their development. The experience of pregnancy includes dramatic changes in a woman’s physical functioning and appearance, as well as significant psychological changes as prospective parents anticipate the birth of the baby. Infertility is the inability to conceive or carry a pregnancy to term after one year of unprotected intercourse. Family planning allows people to decide on the number and spacing of their children. Methods of contraception, including hormones, condoms, intrauterine devices, periodic abstinence and withdrawal, allow families to voluntarily prevent unintended pregnancy. Abortion is used to terminate pregnancy. 3.7 Recognise the risks a mother and baby may face during pregnancy and the birth process, and how can they be minimised. Although prenatal development is highly canalised, there are critical periods — particularly during the first trimester — when embryonic development is highly vulnerable or at risk for disruptions from teratogens, substances or other environmental influences, that can damage an embryo’s growth. Teratogenic effects depend on the timing, intensity and duration of exposure, the presence of other risks, and the biological vulnerability of baby and mother. Risk factors for prenatal development include both medicinal and non-medicinal drugs, such as heroin, cocaine, alcohol and tobacco; diseases such as syphilis, gonorrhoea and HIV/AIDS; physical and biological characteristics of the mother; and physical, biological and chemical environmental hazards. Domestic violence also increases risks to prenatal and postnatal development, as well as developmental risks to the mother. Adequate prenatal nutrition and health care for the mother and her developing baby are associated with successful pregnancy, a normal birth and healthy neonatal development. 3.8 Describe what happens during the birth process, what difficulties may occur, and how they are handled. Labour occurs in three distinct but overlapping stages. The first stage, during which uterine contractions increase in strength and regularity and the cervix dilates sufficiently to accommodate the child’s head, takes from 8 to 24 hours (for a first-time mother). The second stage, when the dilation of the cervix is complete and the birth itself takes place, lasts from 60 to 90 minutes. The third stage, during which the placenta is delivered, lasts only a few minutes. Nonhospital birth centres and home births are two alternatives to hospital-based births. Prepared childbirth is now widely used in both hospital and non-hospital birth settings to help women actively and comfortably meet the challenges of giving birth. Many babies are now birthed by midwives, who provide care to women during pregnancy, childbirth and the weeks following birth. Doulas do not birth babies, but help the mother during labour and birth, and with her newborn. Although pain-reducing medications KEY TERMS adoption study A research method for studying the relative contributions of heredity and environment in which genetically related children reared apart are compared with genetically unrelated children reared together. allele One of several alternative forms of a gene. amniotic sac A tough, spongy bag filled with salty fluid that surrounds the embryo, protects it from sudden jolts, and helps to maintain a fairly stable temperature. canalisation The tendency of many developmental processes to unfold in highly predictable ways under a wide range of conditions. chromosome A threadlike, rod-shaped structure containing genetic information that is transmitted from parents to children; each human sperm or egg cell contains 23 chromosomes, and these determine a person’s inherited characteristics. conception The moment at which the male’s sperm cell penetrates the female’s egg cell (ovum), forming a zygote. critical period A specific time during development when development is particularly susceptible to an event or influence, either negative or positive. Certain types of stimuli are necessary for development to proceed normally. DNA (deoxyribonucleic acid) Long, double-stranded molecules that make up chromosomes. dominant gene In any paired set of genes, the gene with greater influence in determining physical characteristics that are physically visible or manifest. Down syndrome A congenital condition that causes mental disability. https://loop.cloud.microsoft/print/eyJwIjp7InUiOiJodHRwczovL2VkaXRoY293YW51bmkuc2hhcmVwb2ludC5jb20vOmZsOi9yL2NvbnRlbnRzdG9y… 4/5 8/30/24, 12:16 PM Chapter 3: Summary embryonic stage The stage in prenatal development that lasts from week 2 through to week 8. foetal alcohol spectrum disorder (FASD) A congenital condition exhibited by babies born to mothers who consumed too much alcohol during pregnancy. They do not arouse easily and tend to behave sluggishly in general; they also have distinctive facial characteristics. foetal presentation Refers to the body part of the foetus that is closest to the mother’s cervix; may be head first (cephalic), feet and rump first (breech), or shoulders first (transverse). foetal stage The stage in prenatal development that lasts from week 8 of pregnancy until birth. gene A molecular structure carried on chromosomes, containing genetic information; the basic unit of heredity. genomic imprinting A mode of inheritance in which genes are chemically marked so that the number of the chromosome pair contributed by either the father or the mother is activated, regardless of its genetic make-up. genotype The set of genetic traits inherited by an individual. germinal stage The stage in prenatal development that occurs during the first two weeks of pregnancy; characterised by rapid cell division. Also called the period of the ovum. meiosis The process of cell division through which gametes are formed and the number of chromosomes in each cell is halved. It is a process of reduction and division, which ensures that at fertilisation, when the egg and sperm unite, the fertilised ovum contains the normal 23 pairs of chromosomes. midwife The person, usually a woman, who is the primary caregiver to a woman during pregnancy, childbirth and the month or so following delivery. mitosis The process of cell duplication in which each new cell receives an exact copy of the original chromosomes and is identical in genetic make-up to the original. ovum The reproductive cell, or gamete of the female; the egg cell. phenotype The set of traits an individual actually displays during development; reflects the evolving product of genotype and experience. placenta An organ that delivers oxygen and nutrients from the mother to the foetus and carries away the foetus’s waste products, which the mother will excrete. prepared childbirth A method of childbirth in which parents have rehearsed or simulated labour and birth well before the actual delivery date. range of reaction The range of possible phenotypes that an individual with a particular genotype might exhibit in response to the particular sequence of environmental influences they experience. recessive gene In any paired set of genes, the gene that influences or determines physical characteristics only when no dominant gene is present. sex-linked recessive traits Recessive traits resulting from genes on the X chromosome sickle-cell disease A genetically transmitted condition in which a person’s red blood cells intermittently acquire a curved, sickle shape. The condition can, at times, clog circulation in the small blood vessels. sperm Male gametes, or reproductive cells; produced in the testicles. teratogen Any substance or other environmental influence ingested by the mother that can harm the developing embryo or foetus during the prenatal period. twin adoption studies Research that compares twins reared apart with unrelated persons reared together. twin study A research method for studying the relative contributions of heredity and environment in which the degree of similarity between genetically identical twins (developed from a single egg) is compared with the similarity between fraternal twins (developed from two eggs). umbilical cord Three large blood vessels that connect the embryo to the placenta, one to provide nutrients and two to remove waste products. zygote The single new cell formed when a sperm cell attaches itself to the surface of an ovum (egg cell). https://loop.cloud.microsoft/print/eyJwIjp7InUiOiJodHRwczovL2VkaXRoY293YW51bmkuc2hhcmVwb2ludC5jb20vOmZsOi9yL2NvbnRlbnRzdG9y… 5/5