Chapter 2 Flashcards
Summarize the basic argument of Darwin’s theory of evolution and the significance of the theory for the study of development.
According to Darwin’s theory of biological evolution, if there is genetic variation in a species—and if some genes aid members of the species in adapting to their environment and reproducing—those genes will become more common in the population over time through natural selection. There is an interaction between genes and environment, as advantageous genes are only beneficial in a certain environment.
Describe the contributions of ethology and modern evolutionary psychology, including work on life history strategies, to our understanding of genes, development, and behaviour.
Ethologists and today’s evolutionary psychologists use evolutionary theory to understand how certain behaviours have helped humans and other species adapt to their environments. An example is the balance of two main approaches to surviving: a mating strategy (multiple partners) and parental investment strategy (one mate.) Another is the slow life history strategy (high SES, less risk behaviour, others, long-term gratification) and fast life history strategy (low SES, more risk behaviour, self, instant gratification.)
Compare and contrast biological evolution and cultural evolution.
Humans adapt to changes in their environments not only through biological evolution but also through the faster process of cultural evolution.
What are copy number variations (CNVs)?
Instances in which a whole segment of the genome is either deleted or duplicated. CNVs arise spontaneously or are inherited. A CNV is more extensive than a mutation, which is typically a distinct version of a particular gene. CNVs can extend over a large stretch of DNA containing multiple genes. They increase the risks of polygenic disorders.
Summarize what we know about the nature, inheritance, diagnosis, and treatment of sickle-cell disease.
Comes from a genetic mutation which is inherited from parents through recessive gene pairs. A blood test is used to screen all newborns to determine it, and often a life of blood-transfusions, antibiotics, and hydroxyurea drugs are done to treat it (but not cure it)
Summarize what we know about the nature, inheritance, diagnosis, and treatment of Huntington’s disease.
It is a disease that strikes in middle age that disrupts the expression of genes in the nervous system - resulting in motor problems, personality changes, and dementia/cognitive loss. It is a dominant gene. A genetic test is done to determine it - but nothing can really be done about it.
Summarize what we know about the nature, inheritance, diagnosis, and treatment of phenylketonuria
PKU is a metabolic disorder that leads to brain damage and intellectual disability; caused by a single pair of recessive genes that leads to people not having an enzyme needed to metabolise phenylalanine - converting it to a harmful acid that attacks the nervous system. Newborns are screened for PKU via blood test, where they have a diet low in phenylalanine.
What are the major techniques of prenatal diagnosis of such diseases and disorders?
- Ultrasound - can determine genetic defects that show physically.
- Amniocentesis - needle is inserted into the abdomen where amniotic fluid is sampled and fetal cells tested.
- Chorionic villus sampling - inserting a catheter into the chorion and extracting its cells with DNA of the fetus
- Maternal blood sampling - can obtain loose DNA from the fetus that went through the placenta
- Preimplantation genetic diagnosis - diagnosis of embryonic cells from fertilised eggs in a laboratory dish.
Define the main goal of behavioral genetics.
To determine to what extent to which genetic and environmental differences among people/animals are responsible for differences in their physical/psychological traits.
Define the meaning of heritability.
The proportion of all variability in the trait within a large sample of people that can be linked to genetic differences among those individuals.
Define the research methods used to study heritability.
- Twin studies - determining whether identical twins reared together are more similar to each other in traits of interest than fraternal twins reared together. However, identical twins can share similar environments and are often treated the same.
- Adoption studies - determining whether children adopted early in life are psychologically similar to their biological parents, whose genes they share, or are they similar to their adoptive parents, who share environment. However, prenatal environment can affect studies and adoption centres often put children into similar environments as their bio parents and are above-average wealth environments.
- Family studies - Determining whether pairs of siblings who have a variety of different degrees of genetic similarity—for example, identical twins, fraternal twins, full biological siblings, half siblings, and unrelated stepsiblings who live together in stepfamilies
What are the effects of genes, shared environmental influences, and nonshared environmental influences on development?
- Genes - can encode the traits that may or may not be expressed in a person.
- Shared environmental influences - individuals can share common experiences that can make their development similar.
- Nonshared environmental influences - experiences unique to the individual, not shared by other members of the family that can make their development different.
Explain what molecular genetics studies tell us that behavioural genetics studies cannot.
Techniques of molecular genetics (with cheek swabs and genome-wide association studies) are used to identify and study particular gene variants and to compare people who do and do not have them. Unlike behavioural genetic studies, they can tell exactly which genes lead to what traits, how they work and how they interact with environment.
Summarize the main messages of behavioral genetics research on physical traits, intelligence, and temperament and personality regarding the roles of genes, shared environment, and nonshared environment.
Physical and physiological traits are more strongly influenced by genetics than intellectual abilities, which also affect temperament, personality, psychological disorders, and attitudes. Intelligence is heritable, and mental ability differences reflect both genetics and unique environmental factors, while shared influences diminish. Temperament and personality are also genetically influenced, with nonshared environmental factors being more significant than shared. Genes affecting personality contribute to heritable differences in psychological disorders and, to a lesser extent, attitudes and interests.
Compare the average heritabilities of physical traits, intelligence, personality, psychological disorders, and attitudes and interests.
The heritability of human physical, physiological, and psychological traits averages about 50% overall, meaning that genes and environment each account for about half of the variation in human traits. For each one: Body weight (70%), longevitiy (35-40%), IQ (50%), personality (40%)
