WGU - C217 - COMPETENCY 154.1.2: BEGINNINGS - HUMAN GROWTH AND DEVELOPMENT ACROSS
THE LIFESPAN
What is the goal of the field of behavioral genetics?
(correct answers)Behavior genetics is the field that seeks to discover the influence of heredity and
environment on individual differences in human traits and development (Maxson, 2013). Note that
behavior genetics does not identify the extent to which genetics or the environment affects an
individual's traits. Instead, what behavior geneticists try to do is to figure out what is responsible for the
differences among people—that is, to what extent people vary because of differences in genes,
environment, or a combination of these factors. To study the influence of heredity on behavior,
behavior geneticists often use either twins or adoption situations
Chromosomes –
(correct answers)which are threadlike structures made up of deoxyribonucleic acid (DNA).
DNA –
(correct answers)is a complex molecule that has a double helix shape, like a spiral staircase (shown in
Figure 2.3) and contains genetic information.
Genes –
(correct answers)the units of hereditary information, are short segments of DNA.
What is the relation between these terms? (correct answers)The nucleus of each human cell contains all
of these. They help cells to reproduce themselves and to assemble proteins. Proteins, in turn, are the
building blocks of cells as well as the regulators that direct the body's processes.
Dominant
(correct answers)One gene of a pair always exerts its effects; it is dominant, overriding the potential
influence of the other gene, recessive gene. Examples include, brown hair, farsightedness, and dimples.
Recessive
(correct answers)A recessive gene exerts its influence only if the two genes of a pair are both recessive.
Examples include, blond hair, nearsightedness, and freckles.
Genotype
(correct answers)All of a person's genetic material makes up his or her genotype. However, not all of
the genetic material is apparent in our observed and measurable characteristics.
Phenotype
, (correct answers)A phenotype consists of observable characteristics. Phenotypes include physical
characteristics (such as height, weight, and hair color) and psychological characteristics (such as
personality and intelligence).
Provide 3 examples of chromosomal abnormalities
(correct answers)Klinefelter syndrome is a chromosomal disorder in which males have an extra X
chromosome, making them XXY instead of XY. Males with this disorder have undeveloped testes, and
they usually have enlarged breasts and become tall . Klinefelter syndrome occurs approximately once in
every 600 live male births.
Fragile X syndrome is a genetic disorder that results from an abnormality in the X chromosome, which
becomes constricted and often breaks . Mental deficiency often is an outcome, but it may take the form
of mental retardation, a learning disability, or a short attention span. One study revealed that boys with
fragile X syndrome were characterized by cognitive deficits in inhibition, memory, and planning . This
disorder occurs more frequently in males than in females, possibly because the second X chromosome
in females negates the effects of the abnormal X chromosome .
Turner syndrome is a chromosomal disorder in females in which either an X chromosome is missing,
making the person XO instead of XX, or part of one X chromosome is deleted. Females with Turner
syndrome are short in stature and have a webbed neck (Kaur & Phadke, 2012). They might be infertile
and have difficulty in mathematics, but their verbal ability is often quite good (Lleo & others, 2012;
Murphy & Mazzocco, 2008). Turner syndrome occurs in approximately 1 of every 2,500 live female
births.
The XYY syndrome is a chromosomal disorder in which a male has an extra Y chromosome (Bishop &
others, 2011; Stochholm & others, 2012). Early interest in this syndrome focused on the belief that the
extra Y chromosome found in some males contributed to aggression and violence. However, researchers
subsequently found that XYY males are no more likely to commit crimes than are normal XY males .
Provide 3 examples of genetic abnormalities (correct answers)Phenylketonuria (PKU) is a genetic
disorder in which the individual cannot properly metabolize phenylalanine, an amino acid. It results
from a recessive gene and occurs about once in every 10,000 to 20,000 live births. Today,
phenylketonuria is easily detected during infancy and it is treated by a diet that prevents an excess
accumulation of phenylalanine. If phenylketonuria is left untreated, however, excess phenylalanine
builds up in the child, producing mental retardation and hyperactivity. Phenylketonuria accounts for
approximately 1 percent of institutionalized individuals who are mentally retarded, and it occurs
primarily in Whites.
THE LIFESPAN
What is the goal of the field of behavioral genetics?
(correct answers)Behavior genetics is the field that seeks to discover the influence of heredity and
environment on individual differences in human traits and development (Maxson, 2013). Note that
behavior genetics does not identify the extent to which genetics or the environment affects an
individual's traits. Instead, what behavior geneticists try to do is to figure out what is responsible for the
differences among people—that is, to what extent people vary because of differences in genes,
environment, or a combination of these factors. To study the influence of heredity on behavior,
behavior geneticists often use either twins or adoption situations
Chromosomes –
(correct answers)which are threadlike structures made up of deoxyribonucleic acid (DNA).
DNA –
(correct answers)is a complex molecule that has a double helix shape, like a spiral staircase (shown in
Figure 2.3) and contains genetic information.
Genes –
(correct answers)the units of hereditary information, are short segments of DNA.
What is the relation between these terms? (correct answers)The nucleus of each human cell contains all
of these. They help cells to reproduce themselves and to assemble proteins. Proteins, in turn, are the
building blocks of cells as well as the regulators that direct the body's processes.
Dominant
(correct answers)One gene of a pair always exerts its effects; it is dominant, overriding the potential
influence of the other gene, recessive gene. Examples include, brown hair, farsightedness, and dimples.
Recessive
(correct answers)A recessive gene exerts its influence only if the two genes of a pair are both recessive.
Examples include, blond hair, nearsightedness, and freckles.
Genotype
(correct answers)All of a person's genetic material makes up his or her genotype. However, not all of
the genetic material is apparent in our observed and measurable characteristics.
Phenotype
, (correct answers)A phenotype consists of observable characteristics. Phenotypes include physical
characteristics (such as height, weight, and hair color) and psychological characteristics (such as
personality and intelligence).
Provide 3 examples of chromosomal abnormalities
(correct answers)Klinefelter syndrome is a chromosomal disorder in which males have an extra X
chromosome, making them XXY instead of XY. Males with this disorder have undeveloped testes, and
they usually have enlarged breasts and become tall . Klinefelter syndrome occurs approximately once in
every 600 live male births.
Fragile X syndrome is a genetic disorder that results from an abnormality in the X chromosome, which
becomes constricted and often breaks . Mental deficiency often is an outcome, but it may take the form
of mental retardation, a learning disability, or a short attention span. One study revealed that boys with
fragile X syndrome were characterized by cognitive deficits in inhibition, memory, and planning . This
disorder occurs more frequently in males than in females, possibly because the second X chromosome
in females negates the effects of the abnormal X chromosome .
Turner syndrome is a chromosomal disorder in females in which either an X chromosome is missing,
making the person XO instead of XX, or part of one X chromosome is deleted. Females with Turner
syndrome are short in stature and have a webbed neck (Kaur & Phadke, 2012). They might be infertile
and have difficulty in mathematics, but their verbal ability is often quite good (Lleo & others, 2012;
Murphy & Mazzocco, 2008). Turner syndrome occurs in approximately 1 of every 2,500 live female
births.
The XYY syndrome is a chromosomal disorder in which a male has an extra Y chromosome (Bishop &
others, 2011; Stochholm & others, 2012). Early interest in this syndrome focused on the belief that the
extra Y chromosome found in some males contributed to aggression and violence. However, researchers
subsequently found that XYY males are no more likely to commit crimes than are normal XY males .
Provide 3 examples of genetic abnormalities (correct answers)Phenylketonuria (PKU) is a genetic
disorder in which the individual cannot properly metabolize phenylalanine, an amino acid. It results
from a recessive gene and occurs about once in every 10,000 to 20,000 live births. Today,
phenylketonuria is easily detected during infancy and it is treated by a diet that prevents an excess
accumulation of phenylalanine. If phenylketonuria is left untreated, however, excess phenylalanine
builds up in the child, producing mental retardation and hyperactivity. Phenylketonuria accounts for
approximately 1 percent of institutionalized individuals who are mentally retarded, and it occurs
primarily in Whites.
