Chapter 2 Life-Span Development Flashcards
Natural selection
an evolutionary process by which individuals of a species that are best adapted are the ones that survive and leave the most fit offspring
Adaptive behavior
behavior that promotes an organism’s survival in the natural habitat, because an organism possess characteristics needed for survival
Evolutionary Psychology
emphasizes the importance of adaptation and reproduction to ensure survival
- offspring that adapts, develops behaviors, and possesses self-productive traits to survive
Evolutionary developmental psychology: Interest has grown in using the concepts of evolutionary psychology to understand human development
Psychology mechanisms are domain-specific: ex: we developed sets of problem-solving skills for recurring problems like finding food
Evolutionary Psychology: Connecting evolution and life-span development:
- The benefits conferred by evolutionary selection decrease with age
- Natural selection primarily operates during the first half of life and during reproductive viability
- Older adults weaken biologically and need culture-based resources such as cognitive skills, literacy, medical technology and social support.
Evaluating Evolutionary Psychology
Criticisms:
- Does not adequately value social/environmental factors
- Relies on after-the-fact explanations
- Cannot be tested scientifically
Evolution does not dictate behavior
Evolution occurs on a time scale that does not lend itself to empirical study
- Thus the ideas coming out of evolutionary psychology are best tested by studying genes in humans and other species, and their links to traits and behaviors.
The Collaborative Gene
Human life begins as a single cell
The nucleus of each cell contains chromosomes
Chromosomes: threadlike structures made up of deoxyribonucleic acid
DNA: a complex double-helix molecule that contains genetic code or info
Genes: a unit of hereditary information composed of DNA
- help cells to reproduce themselves
- manufacture the proteins that maintain life
Each gene has its own location-its designated place on a particular chromosome,
Today researchers strive to discover the specific locations of genes that are linked to certain functions and developmental outcomes
Genetic expression is affected by their environment…
hormones in the blood can turn genes “on” or “off”
Certain genes are turned on or off as a result of exercise, mainly through methylation:
- Tiny molecules attach themselves to the outside of a gene, making the gene less capable of receiving and responding to biochemical signals from the body
- Stress, exercise, nutrition, radiation, temperature, and lack of sleep can negatively influence gene expression.
Genes and Chromosomes
All of the cells in the body, except the sperm and egg, have 46 chromosomes in 23 pairs
Mitosis: the cellular reproduction in which the cell’s nucleus duplicates itself into two new cells
Meiosis: Cell division forming eggs and sperm (or gametes)
Fertilization: the reproductive stage when egg and sperm, fuse to form a zygote
- Zygote: a single cell, formed through fertilization, in which 23 unpaired chromosomes from the egg and 23 unpaired chromosomes from the sperm combine
Genes and Chromosomes: Source of Variability
Combining the genes of two parents in offspring increases variability in the population.
- the chromosomes are brought together in the zygote in a unique combination
- in identical twins (monozygotic), a single zygote splits into two genetically identical replicas and becomes two individuals
- in fraternal twins (dizygotic), two eggs fertilized by different sperm create two nonidentical zygotes as genetically similar as ordinary siblings
Mutated gene
a permanently altered segmented of DNA
Susceptibility genes
genes that make the individual more vulnerable to specific diseases or accelerated aging
longevity genes
genes that make the individual less vulnerable to certain diseases and more likely to live to an older age
genotype
a person’s genetic material
phenotype
how an individual’s genotype is expressed in observable and measurable physical psychological characteristics
expression is influenced by environmental factors.
- a genetic potential for height may be stunted by a lack of access to proper nutrition
Sex-linked genes
When a mutated gene is carried on the X chromosome, the result is called X-linked inheritance
Most X-linked inherited diseases manifest in males, who have only one X chromosome.
Dominant-recessive gene principle:
one gene of a pair always exerts its effects, overriding the potential influence of the other gene
Genetic Imprinting
occurs when the expression of a gene has different effects depending on whether the gene is passed on by mother or father
- a chemical process prevents one member of the gene pair from expressing itself
imprinting is normal and can go awry, disturbing development and leading to growth disorders or cancer.
polygenic inheritance
many different genes interacting, plus environmental influences, determine a characteristic or developing disease.
gene-gene interaction
studies focusing on the interdependence of two or more genes in influencing characteristics, behavior, diseases, and development
down syndrome
a form of intellectual disability caused by the presence of an extra copy of chromosome 21
- can cause intellectual and physical issues
chromosomal abnormalities known as sex-linked involve the presence of an extra X or Y chromosome or the absence of one X chromosome in females.
Klinefelter syndrome
a sex-linked chromosomal disorder in which males have an extra X chromosome, making them XXY instead of XY
characteristics are underdeveloped testes, enlarged breasts and becoming tall
fragile X syndrome (FXS)
a sex-linked disorder involving an abnormality in the X chromosome, which becomes constricted and often breaks
- can cause intellectual disability, learning disability, or short attention span
turner syndrome
a sex-linked disorder in females in which either an X chromosome is missing or the second X chromosome is partially deleted
- can cause intellectual disability and sexual underdevelopment
XYY Syndrome
a sex-linked disorder in which males have an extra Y chromosome
- can cause above-average height
phenylketonuria (PKU)
a genetic disorder in which an individual cannot properly metabolize an amino acid called phenylalanine
phenylketonuria (PKU)
a genetic disorder in which an individual cannot properly metabolize an amino acid called phenylalanine
- if left untreated, it results in intellectual disability and hyperactivity
sickle-cell anemia
a genetic disorder that affects the red blood cells and occurs most often in people of African descent
- red blood cells become hook-shaped and cannot carry oxygen properly
Dealing with genetic abnormalities
- each individual carried DNA variations that predispose the person to serious physical disease or mental disorder
- genes that are missing, nonfunctional, or mutated can contribute to disorders
identifying genetic flaws enables medical professions to
- predict an individual’s risk
- recommend healthy practices
- prescribe the safest and most effective drugs
Prenatal Diagnostic Tests
a # of tests can indicate whether a fetus is developing normally
- ultrasound sonography
- brain-imaging techniques
- chorionic villus sampling
- amniocentesis
- material blood screening and cell-free DNA
- noninvasive prenatal diagnosis (NIPD)
- fetal sex determination
infertility
the inability to conceive a child after 12 months of regular intercourse without contraception
in vitro fertilization (IVF)
a process in which eggs and sperm are combined in a laboratory dish by experts
- one or more of the resulting by zygotes in transferred into the woman’s uterus
- multiple zygotes can increase health risks
- IVF success rate depends on the mother’s age and other factors
adoption
is a social and legal process that establishes a parent-child relationship b/w persons unrelated at birth.
- U.S. couples are adopting a wide variety of children
behavior genetics
the field that seeks to discover the influence of herdity and environment on individuals differences in human traits, development and behavior.
twin study
the behavioral simililarity of identical twins is compared with the behavioral similarity of fraternal twins
adoption study
seeks to discover whether behavioral and psychological characteristics or adopted children are more like those of their adoptive parents or biological parents
- adoptive parents provided the home environment
- biological parents contributed to their heredity.
passive genotype-environment correlations
occur b/c biological parents provide a rearing environment for the child
evocative genotype-environment correlations
occur b/c a child’s genetically-influenced characterisitcs elicit certain types of environments
active (niche-picking) genotype-environment correlations
occur when children seek out environments that they find compatible and stimulating and suited for their genetically influenced abilities
epigenetic view
development is the result of an ongoing, bidirectional interchange b/w heredity and environment
gene x environment (G x E) interaction
the interaction of a specific measured variation in the DNA and a specific measured aspect of the environment
- the epigenetic mechanisms involve the actual molecular modification of the DNA strand as a result of environmental inputs in ways that alter gene functioning
Conclusions about Heredity-Environment Interaction
- Genes produce proteins—or not— in many different environments throughout the life span
- complex behaviors are influenced by genes and environments in a way that gives people a propensity for a particular developmental trajectory
- we also can author a unique developmental path by changing the environment
