How Heredity Influences Variations In Human Beings

Heredity and its influence on human traits

Discuss about the Skill Discretion and Decision Authority.

Heredity in the study of human genetics is important in helping to explain the inheritance of physical, physiological and psychological traits in human beings. The major influences of heredity in human beings are the environment and the genetic constitution of individuals. Heredity is also said to influence learning abilities in human beings. This paper focuses on a broader definition of heredity and how heredity influences variations in human beings as genetics influences physiological and psychological traits. The paper also seeks to explain how the environment is also responsible in shaping traits and finally how the acquired and inherited traits influence individual differentiation and learning.

According to Ilies, & Dimotakis, (2015) heredity in genetics refers to the passing on of certain physical or mental characteristics or traits from an organism to its offspring or from one generation to another. The traits can either be passed on through sexual or asexual reproduction. However in human beings, it’s mainly through sexual production where genetic information is passed on from parent to offspring.

Kagan, (2018) argues that heredity involves inheritance and variation which is also affected by the environment that an organism. In other words, the traits of an organism are influenced by both the nature and the nurture of the organism. While the nature refers to the inherited characteristics, nurture refers to the environmental conditions that are also responsible in shaping the traits and the personality. Examples of the characteristics that are inherited from parent to offspring in humans include height, skin color and hair among others.

The inherited traits are carried in the genes of the organism. Genes refer to very small biochemical structures found in the cells of all organisms. The genes contain a chemical component known as deoxyribonucleic acid (DNA). Several chains of DNA stranded together forms chromosomes. The DNA contains coded information that controls the functioning and growth of all the body parts, organs and organ systems. The genes determine the formation of proteins and hormones thus influencing growth. Differences in the genes therefore cause different constitution of proteins and other growth factors hence causing differences in the individual traits in the organisms. The interaction of genes with other genes and the environment may form a basis for variation through various processes.

The study of genetics and heredity was pioneered by Charles Darwin where he argued that desirable traits are passed on to the offspring through sexual production therefore causing natural selection. According to Darwin, natural variations through sexual reproduction were the only determinants of heredity and new traits in a given population. More information regarding genetics and heredity was not available until 1866 when Gregor Mendel, a German monk and a scientist, published his work about numerous experiments he had conducted with breeding pea plants (Waddington, 2016).

Nature and Nurture controversy

Mendel explained how an offspring acquires distinct characteristics from both of the parents. Mendel also explains the principle of dominance where he argues that some traits may be dominant while others recessive. He argues that the dominant characteristics are expressed in the individual while the individual may still have recessive characteristics that are not expressed due to their recessive nature. Mendel also used probability to explain the criteria through which traits are passed on to the offspring during the formation of sex cells. Mendel also explained a factor called co dominance where the two forms of a trait are equally expressed in an organism. Finally, Mendel also explained incomplete dominance where when it happens, an individual inherits a blend of several traits (Richards, 2016).

The DNA molecule according to Seligman, & Csikszentmihalyi, (2014) has made all organisms to produce predictable offspring. However, the offspring often vary in characteristics and traits due to variation. While genetics remain the biggest source of variation in organisms, environmental factors also largely contribute to variation. The main processes of gene variation however include; mutation, gene flow, genetic drift, gene deletion and alteration. James Watson and Francis Crick explains mutation as the changes that occur to a DNA molecule through cell division. The changes are usually corrected to retain the right information in the DNA molecule. However, if the alterations are not corrected, variation occurs. The variation may contribute to a disability or difference in original features and characteristics (Buss, & Plomin, 2014).

Heredity influences intellectual capacity and emotional capability that are the two main determinants of psychological behavior and personality. Heredity also influences physical characteristics that in turn influences the body physiology and functioning to help acquire the genetic traits in the DNA The major emotional traits that have been inherited include shyness, introversion and extroversion, schizophrenia and alcohol dependence among other factors. Genes can either influence the environmental conditions or be influenced by the environment. Research has proven this assertion by explaining that there are some features that develop in humans due to exposure to certain environs.

Several other experiments have been concluded to determine how heredity influences psychological traits. In one of these experiments, it was identified that blind children and those with sight start smiling at the same stages of development (Rothe, 2017). This was amid claims that smiling is learnt through observation thus helping to conclude that behaviors are instinctual and inherited. In addition, there have been observed universality of emotions among all human beings even among hunter gatherer societies.

The Relationship between Genes and Environment

According to Plomin, DeFries, Knopik, & Neiderhiser, (2016) genetics is important in determining learning, growth and development. Genetics influence the developmental stages in children and secondary characteristics and also ageing throughout a person’s life. This can be proven by the fact that the presence or absence of a gene has various influences on these characteristics. This can be proven through the Mendelian law. A control experiment that helps to determine the truthfulness of this assertion is selective breeding that may alter the emotional or cognitive ability and capacities of people in a certain society.

The genetic make-up of an individual influences the physiological and psychological traits of an individual but in varying proportions (Theorell, et al 2016). Psychological and physiological traits are also influenced by environmental factors such as exposure to certain chemicals or the climate. Controversy as to whether it’s the genetic make-up or the environment that influences human behavior has stimulated various debates which has come to be known as nature-nurture controversy. Several revelations have however confirmed that personality is influenced by both genetics and the environment in varying degrees. Environmental factors influence personality and physiological functions since they influence how certain genes are expressed in an individual. For instance, some people may develop allergic reactions to various environmental factors such as temperature or climate. In addition, the susceptibility of certain genetic disorders varies greatly in relation to the environment and geographical region.

The relationship between genes and the environment can be explained in 3 various ways. These include passive, active or evocative argues Zuckerman, (2014). The passive gene- environment correlations explains the relationship between certain traits and an environment that may favor such traits without much involvement with the genetic outcomes. For instance, an irritable child raised by irritable parents may be argued to be so not necessarily through inheritance of the irritability trait but by the exposure to the environment he/she has been brought up in.

Dochtermann, Schwab, & Sih, (2015) in the evocative gene-environment co relations, certain human behaviors exhibit different reactions to the environment. The environment often predisposes human beings to behaviors that may not be similar to the predisposing environment. For instance, scarcity of food may make people to lead miserable lives and remain dull even after food is made available. Finally the active gene environment co relations are the outcomes of the choices people make in their environments depending on their genetic constitution.

Some of the major studies that can have been carried out to explain the relationship between genes behavior and the environment include the adoption and the twin studies argues Charlesworth, & Charlesworth, (2017). In the adoption studies, children of different genetic origin are raised together with similar environmental conditions and then their psychological attributes are tested to examine the influence of the environment on the similarity of their psychological and physiological attributes. From the results the environment is seen to play a major role in the development of character and behavior in human beings (McBride, Birmingham, & Kinney, (2015). Similarly, in the twin studies, identical twins are raised in two separate environments. The result of the similarity and differences in their behavior and character traits also explains that genetics are responsible for the psychological and physiological traits in humans since the intelligence is almost always similar even if raised in different environments. 

The environmental influence on physiological functioning is clear based on the fact that the environment determines the availability of food that helps organisms to grow holds Gilbert, (2016). It is the environment that dictates the processes, the work, the amount of food and the type of food that individuals consume. Food then affects growth which is usually multidirectional and multidimensional occurring throughout a person’s life. Human growth and development is also pliable. This assumption argues that most of human characteristics such as intelligence, strength or weight can be improved with practice. This therefore explains the role of the environment in influencing and determining human characteristics and traits.

Psychologists have attempted various theories of explaining personality and the influence that environment has on certain behaviors. Apart from the behavioral theories, several other personality based theories have been put forward to explain the influence of the environment on behavior. Some of these theories include the psychosexual theory advanced by Sigmund Freud, the psychosocial theory advanced by Eric Ericson and the social cognitive theory by Albert Bandura.

The psychosocial and the psychosexual model emphasizes on the importance of parenting especially in childhood in order to explain the development of various psychological and physiological traits or tendencies. Both theories explains how development takes place in the stages and argues out that a person’s personality is influenced by the environment and more importantly the parenting as a person goes through the earlier stages. The environment one grows in is therefore said to play a very major role in the development of both psychological and physiological traits (Renninger, Hidi, Krapp, & Renninger, 2014).

In the social learning theory, Albert Bandura postulates that human beings learn from one another and most importantly through observation. Bandura believed that in every society, there are models whom people admire and advise one another to take after. He believes that human beings act or behave in a certain way because they have seen others behave so. The model is therefore very important in not only explaining the development of character traits but also learning and differentiation.

Human cognitive development and continuous learning makes human beings to not only learn to suffice their immediate needs but to also seek long term solutions to the challenges that face humankind argues Hutt, (2017). This is done through a process of learning and reflection. In addition, human beings also associate with each other and help to improve each other’s abilities and well-being. In contrast to this, human beings can be said to be selfish and being motivated by self-interests which makes them conspire to harm and outdo one another in order to achieve various ends. All these behaviors can be linked to the heredity of genes and the influence of the environment.

According to Sigmund Freud however, behavior is determined by life instincts. This tends to undermine the role of nurture in determining human traits. In his psychoanalytic theory, Freud argues out that human behavior is motivated by life instincts. The instincts serve to satisfy biological needs. In contrast, Freud also explains the role of parenting in determining the personality of an individual. In his theory, Freud argues that poor parenting is the primary cause of undesired behavior and poor traits, what he calls fixations (Frijda, 2017).

This theory can be used as a tool to explain how nature determines the psychological and physiological characteristics of human beings as well as the role environment has in influencing how these characteristics are expressed in various individuals according to the parenting. However, Freud can be criticized as he assumes human beings are born with the same level of intelligence where full actualization depends solely on the quality of parenting. In addition to this, not all human behaviors are determined by biological needs. Human beings also seek to understand and change their environments (Buss, 2015).

According to Gottlieb, (2014) while cognition and learning is arguably influenced by genetic constitution of a person, psychologists have also developed various theories that explain how learning is made effective by the environment in both animals and human beings. There are two famous theories that have been advanced on learning. These theories include the theory of classical conditioning by Ivan Pavlov and the theory of operant conditioning by skinner. In the classical conditioning theory, Pavlov argues that all behavior is conditioned. This means that behavior is learned through pairing a neutral stimuli to an unconditioned stimulus to produce a neutral response. He then argues that if this continuous for some time, the conditioned stimulus will be able to produce the neutral response even without the neutral stimulus.

In the operant conditioning, skinner argues how a behavior is learned if it is performed repeatedly (Eagly, & Wood, 2017). These two theories therefore help to explain how behavior is influenced by environmental factors. The inheritance of some learned behaviors in both animals and humans then highlights the role of genetics in behavior modification and learning. Cognition in human beings can be said to be the motivating factor in association. This is through understanding the self and understanding how self-modification can have various influences on the behavior of other people. The fact that human beings are influenced by how specific individuals among a group behave highlights the role of the environment in influencing and determining behavior.

Jean Piaget was also among the theorists who also believed that the environment had power to shape individuals as opposed to their genetic makeup. While still holding that growth was biologically related and interconnected with the environment that a person was brought up in. just like other theorists, Jean Piaget also believed that development starts at birth and is shaped based on how a person reacts with the environment at various stages of growth. Piaget refers to this personal development as biological maturation Morss, (2017). His theory is mainly centered on human intelligence, how it is acquired, how it influences growth and how it is passed on.

Piaget developed a social learning model known as the theory of cognitive development. Jean Piaget came up with four stages of development which include the sensorimotor, pre operational, concrete operational and formal operational stage. The sensorimotor represented the growth stage before one learns any language. A human being thus relies on their senses hence the word sensorimotor. This is mainly in children where the activities they engage in are instinctual and reflexive. The second stage is when a person understands a language but one does not have logic. The person can only express themselves but cannot manipulate information. The third concrete operational stage is a stage where one is capable of using logic and one becomes adult-like in behavior and reason. The final stage is the formal operational stage where one has fully developed in function and reason. Someone is also able to think abstractly.

Piaget emphasized that from birth, human beings make constructs of their immediate environment and what they learn and understand is mainly centered on how they understand their immediate environment Piaget, & Inhelder, (2015). Piaget also argued that knowledge acquired through learning is only build upon what a person already knows. This clearly shows that learning does not exist independent of the environment. Of important however is the assertion that language is at the center of learning and cognitive development. This forms the basis for the argument that learning is a process of assimilation and accommodation. These two processes define learning at all stages of life.

The theory of moral development by Lawrence Kohlberg is another model that can be used to explain how heredity influences differentiation and learning. The theory has been mainly based on the work of Jean Piaget’s theory of moral reasoning. Kohlberg’s theory of moral reasoning emphasizes on how reason develops in stages independent of the environment one is brought up in explains Peters, (2015). According to Kohlberg, morality and reason is a matter of age of a person and not the environment. However, the morality is not tied to age and this helps to explain why human beings at different ages reason differently. The theory explains morality in three major stages which are pre conventional morality, conventional morality and post conventional morality. Each stage with a better moral reasoning capacity. Kohlberg believed that heredity had a lot to do with the development of all the stages (Renninger, Hidi, Krapp, & Renninger, 2014).

Conclusion

In conclusion, it is critical to note that heredity, which is the study of inheritance and variation highly influences a person’s psychological and physiological characteristics. This is because genetic information influences the formation of organs and organ systems in the body and these further influence the physiological and the psychological functioning of the body. The major studies in inheritance and variation include the adoption and twin studies. The environment is also responsible in influencing psychological and physiological traits as it influences the extent to which the traits are expressed. Genetically inherited characteristics and the environment also influence learning, cognitive development and learning.

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