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Lifecycle or lifespan development is the field in psychology that studies how people change with time. These changes could be biological, including body changes and motor skills; cognitive, including thought and language; and psychosocial, including emotions, personality and relationships with other people. Life cycle development starts in the womb at conception and continues throughout the individual’s life. Other important stages of development are; birth, infancy, adolescence, adulthood, old age and finally death. Though some aspects of development may be strongly influenced by how the fetus develops in the womb, the genes one receives from his/her parents interact with the environmental factors after the individual is born such as the food one eats, parenting, experiences, friends, family relationships, culture and school. All this help us understand the influences that help contribute to growth and development. Our genes are the bio-chemical units of heredity that make each of us a distinctive human being.
The genes we share make us people rather than dogs or tulips. But might our individual genetic make-ups explain why one person is outgoing, another is shy, or why one person is slow-witted while another is smart? Some developmental psychologists focus on explaining how our genetic background can determine not only how we look, but also how we behave, how we relate to others i.e. matters of personality. These professionals explore ways to identify how much of our potential as human beings is provided or limited by heredity. In this article we’ll take a closer look at how biological influences (genes) help shape individual development. We’ll learn more about how genetic disorders can impact one’s psychology and development and also how our experiences interact with genetics. Lastly we’ll learn on ways to take care of a child while in the womb and after to ensure they reach their maximum genetic potential.
How Biological Influences Determine Development.
Development begins at that moment when chromosomes in the sperm and ovum join together in the fallopian tubes to form 23 pairs in an entirely new cell called a zygote. Chromosomes are composed of molecules of DNA containing the genes. Genes are pieces of genetic material that control or influence traits. It is these genes that will guide cell activity for the rest of the individual’s life. A gene controlling some specific characteristic always appear in the same place (the locus) on the same chromosome in every individual of the same species. For example, the locus of the gene that determines whether a person’s blood is type A, B or O is on chromosome 9. Genes also determine the nature and function of every cell in the body. For instance, they determine which cells will ultimately become part of the heart and which will become part of the muscles of the leg. It is the genes that establish how different parts of the body will function; how rapidly the heart will beat, or how much strength a muscle will have. The genetic instructions passed down from both parents’ influence how an individual develops and the traits they will have.
Combinations of genes from the father in the sperm and from the mother in the ovum create a unique genetic blueprint the genotype- all of the genes that a person has inherited-that characterizes that specific individual. The actual expressions of those genes that can be identified by directly observing the individual is the phenotype. The phenotype can include physical traits, such as height and color of the eyes, as well as non-physical traits such as shyness, a high strung temperament or a thirst for adventure. Whether or not a gene is expressed depends on two different things: the interaction of the gene with other genes and the continual interaction between the genotype and the environment. The simplest genetic rule is the dominant-recessive pattern in which a single dominant gene strongly influences phenotype.
If a child receives a single dominant gene, for a trait from one parent, the child’s phenotype will include the trait determined by that gene. In contrast, a child’s phenotype will include a recessive trait only if she inherits a recessive gene from both parents. Eye color is one example of dominant-recessive genes at work. The gene for brown eyes is dominant and the gene for blue eyes is recessive. If one parent hands down a dominant brown eye gene while the other parent hands down a recessive blue eye gene, the dominant gene will win out and the child will have brown eyes. A person’s sex is also determined in the womb. An individual inherits 23 pairs of chromosomes.
Twenty- two of these pairs of chromosomes, called autosomes, contain most of the genetic information controlling highly individual characteristics like hair color, height, body shape, temperament, aspects of intelligence and also all those characteristics shared by all members of our species, such as pattern of physical development. The twenty-third pair, the sex chromosomes, determines the child’s sex. One of the two sex chromosomes, the X chromosome, is one of the largest chromosomes in the body and carries a large number of genes. The other, Y chromosome, is quite small and contains only a few genes. Zygotes containing two X chromosome i.e. XX develops into female and zygote containing one X and one Y chromosome i.e. XY develops into male.
Though development in the womb usually produces a normal infant, genetic instructions are not infallible and can go off track at times. Sometimes when a sperm or ovum is formed, the number of chromosomes may divide unevenly, causing the organism to have more or less than the normal 23 chromosomes. When one of these abnormal cells joins with a normal cell, the resulting zygote will have an uneven number of chromosomes. In every case, the result is some type of syndrome with a set of distinguishing characteristics. For example, Down Syndrome in this case, the child has three chromosomes at the site of the 21st chromosomes instead of the normal two. This can result to mental retardation and abnormal physical development.
How Interaction Between The Genes And The Environment Determine Development. Although genes play an important role in human development, they alone do not determine who we are. It is important to note that the environment an individual is exposed to both in womb and throughout the rest of his or her life can also impact how the genes are expressed. For example, exposure to harmful drugs while in womb can have a dramatic impact on later child development. Exposure to teratogens, which are noxious substances or other factors that can disrupt prenatal development can prevent the individual from reaching his or her inherited potential.
For example, prenatal exposure to X rays can disrupt the migration of brain cells, causing mental retardation (Schull, Norton, & Jensh, 1990). Environmental factors such as the food we eat, the air we breathe, the physical and social contexts we experience, our relationships and our continual ongoing interactions at work, at home and at play are necessary for a person to develop well. Heredity and environment work together to produce person’s intelligence, temperament, height, weight, ability to read and so on. Height is a good example of a genetic trait that can be influenced by environmental factors. While a child’s genetic code may provide instructions for tallness, the expression of this height might be suppressed if the child has poor nutrition or a chronic illness.
Proper Care During And After Pregnancy
From the above information we can see that most of an individual’s characteristics, from sex, eye color, height, intelligence are determined in the womb because of the genes, great care of the foetus is important to ensure the development is not impaired. Genetic codes are not irrevocable signals for this or that pattern of development or this or that disease. The eventual developmental outcome is affected by the specific experiences the individual may have from conception onwards. Maintaining good nutrition and obtaining pre-natal care is necessary. According to Institute of Medicine, 1990 development before and during pregnancy is important to defend against specific defects and diminish overall vulnerability. Mineral and Vitamins including iron, zinc, calcium and vitamin A have been proved to be essential for the normal development of the fetus. Early, competent, pre-conceptual and prenatal care is also vital as they not only help birth defects but also reduces the rate of low- birth weight.
Avoiding teratogens is vital to avoiding defects on the unborn infant. The American Academy of Pediatrics recommends that parents read, sing, talk and play music for their baby inside the womb. It is believed that cognitive development starts inside the womb, and hearing music and parents’ voices helps develop a baby’s emotional state. In addition, many researchers believe that hearing a mother’s and father’s voices regularly before birth helps babies learn who their parents are so that those voices can better soothe them after they are born. The Mayo Clinic has also published several studies showing that babies, who are read, played music, sung or spoken to regularly have shown signs of being calmer babies, and may have a better emotional connection with their parents or caregivers.
After birth environmental factors such as the food we eat, the air we breathe, the physical and social contexts we experience, our relationships and our continual ongoing interactions at work, at home and at play are necessary for a person to develop well. For example while considering the type of parenting, permissive parents set few rules and rarely punish misbehavior. Their children will be less likely to adopt positive standards of behavior. Children raised by authoritarian parents who resort to discipline, might develop low self-esteem and are more socially withdrawn (Kaufman & Cicchetti, 1989).
They tend to be more aggressive and are more likely to become juvenile delinquents (Bower, 1990). According to Baumrind, 1993 the best approach to child rearing is authoritative parenting. These parents are warm and loving, yet insist their children behave appropriately. They encourage independence within well-defined limits, show willingness to explain the reasons for the rules, and permit children to verbalize their disagreement with them. Their children are more likely to become socially competent, independent and responsible.
While some aspects of development may be strongly influenced by biology, environmental influences may also play a role. For example, the timing of when the onset of puberty occurs is largely the results of heredity, but environmental factors such as nutrition can also have an effect. While the genetic instructions a child inherits from his parents may set out a road map for development, the environment can impact how these directions are expressed, shaped or event silenced. The complex interaction of nature and nurture does not just occur at certain moments or at certain periods of time; it is persistent and lifelong. Clearly, genetics have an enormous influence on how a child develops. However, it is important to remember that genetics are just one piece of the intricate puzzle that makes up a child’s life. Environmental variables, including parenting, culture, education and social relationships also play a vital role.
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