Chapter 2 Biological Beginnings Flashcards
identical twins
Twins from same fertilized egg
fraternal twins
Twins from different fertilized eggs
Natural selection
is the evolutionary process by which those individuals of a species that are best adapted are the ones that survive and reproduce.
Charles Darwin Famous Book
The Origin of Species (1859),
Adaptive behavior
behavior that promotes an organism’s survival in the natural habitat.
evolutionary psychology
Branch of psychology that emphasizes the importance of adaptation, reproduction, and “survival of the fittest” in shaping behavior.
Evolutionary Developmental Psychology
Branch of PSYC that focuses on Adaptation, reproduction and survival of fittest from developmental side view
Why humans have extended childhood?
-Human brains take long time to develop fully
- Human societies’ are complex and to fully understand complexities humans take time
what are evolved mechanisms?
behaviours that were passed on from generation to another. Such as hunting, calculation, farming. They eventually become modules
genetic code
—information that helps us grow from a single cell to a person made of trillions of cells, each containing a replica of the original code.
chromosomes,
threadlike structures made
up of deoxy-ribo-nucleic acid, or DNA
DNA / Deoxy-ribo-nucleic
complex molecule that has a double helix shape (like a spiral staircase) and contains genetic information
Genes
units of hereditary information, are short segments of DNA,
Function Of genes
- help cells to reproduce themselves
- assemble proteins.
Proteins
- Materials produced by genes
-building blocks of cells
-as well as the regulators that direct the body’s processes (
human genome
the complete set of developmental information for creating proteins that initiate the making of a human organism (
genome-wide association method
- blood sample is used to collect DNA
- Each DNA is purified and scanned to see markers of genetic variations.
- Place of variation in the sample of the person with disorder is supposed to have caused the issue / disorder
Linkage analysis
goal is to discover the location of a gene(s) in relation to a marker gene (whose position is already known), is often used in the search for a disease gene(s)
Next-generation sequencing
is a term that is now used to describe the vast increase in genetic data generated at a much reduced cost and in a much shorter period of time
mitosis
Cellular reproduction in which the cell’s nucleus duplicates itself with two new cells being formed, each containing the same DNA as the parent cell, arranged in the same 23 pairs of chromosomes.
meiosis
A specialized form of cell division that forms eggs and sperm (also known as gametes). During meiosis, a cell of the testes (in men) or ovaries (in women) duplicates its chromosomes but then divides twice, thus forming four cells, each of which has only half of the genetic material of the parent cell. By the end of meiosis, each egg or sperm has 23 unpaired chromosomes.
fertilization
A stage in reproduction during which an egg and a sperm fuse to create a single cell, called a zygote.
zygote
A single cell formed through fertilization. In the zygote, the 23 unpaired chromosomes from the egg and the 23 unpaired chromosomes from the sperm combine to form one set of 23 paired chromosomes—one chromosome of each pair from the mother’s egg and the other from the father’s sperm. In this manner, each parent contributes half of the offspring’s genetic material
How do the genes manage to get passed from generation to generation and end up in all of the trillion cells in the body?
Three processes explain the heart of the story: mitosis, meiosis, and fertilization
Number of chromosomes in each cell
46 in pairs of 23
chromosome mix for Male
XY
chromosome mix for Female
XX
Fraternal twins = dizygotic twins
Twins develop when two eggs are each fertilized by a different sperm,
Identical twins = monozygotic twins
develop from a single zygote that splits into two genetically identical replicas, each of which becomes a person.
mutated gene
permanently altered segment of DNA.
genotype
person’s genetic material makes up non observable and non measurable characteristics. E.G personality and intelligence
phenotype
consists of observable characteristics. Eg - height, weight, and hair color
What are GENETIC PRINCIPLES
dominant-recessive genes, sex-linked genes,
genetic imprinting, polygenically determined characteristics.
dominant gene
one gene of a pair always exerts its effects over riding potential influence of the other gene,
recessive genes
A pair of genes that gets influenced by other gene losing its potential influence.
If you inherit a recessive gene for a trait from each of your parents, you will show the trait.
Can two brown-haired parents have a blond-haired child?
If both have a recessive gene for blond hair and a child inherits both recessive genes for blond hair
Why , most individuals who have X-linked diseases are males?
Because males have only one copy of X chromosome. So if the mutated gene is on X chromosome then Males do not have a back up of another X Chromosome to reduce /override the effect of mutated gene
What if women have X Chromosome linked Disorder ?
Women become carriers of that disorder
Genetic imprinting
Genetic imprinting occurs when genes have differing effects depending on whether they are inherited from the mother or the father .A chemical process “silences” one member of the gene pair. For example, as a result of imprinting, only the maternally derived copy of a gene might be active, while the paternally derived copy of the same gene is silenced—or vice versa
Polygenic Inheritance
Most characteristics are determined by the interaction of many different genes; they are said to be polygenically determined .
gene-gene interaction
interdependence of two or more genes in influencing characteristics, behavior, diseases, and development
Gamete
A specialized form of cell division that forms eggs and sperm (also known as gametes).
Chromosomal Abnormalities
Sometimes a gamete is formed in which the male’s sperm and/or the female’s ovum do not have their normal set of 23 chromosomes. The most notable examples involve Down syndrome and abnormalities of the sex chromosomes
Explain Down Syndrome
- fallout of Chromosomal Abnormalities
- Appears once in 700 live births
- Has extra copy of 21 chromosome - not known why
- round face, a flattened skull, an extra fold of skin over the eyelids, a protruding tongue, short limbs, and disabilities involving motor and intellectual development.
Explain sex linked Chromosomal Abnormalities
Males have XY and females have XX chromosomes. So for humans at least one copy of X chromosome is vital. In sex linked chromosomal abnormalities there is a presence of extra chromosome either X or Y
Klinefelter syndrome (XXY) - Chromosomal Abnormality
-Males have an extra X chromosome, making them XXY instead of XY
- Undeveloped testes
- enlarged breasts
- significant impairment in language, academic, attentional, and motor abilities in boys
- Happens 1/800 live male births
Fragile X syndrome - Chromosomal Abnormality
- Weak, narrowed broken X chromosome
- Happens more in Males than Females, because females have additional X chromosome to back up
- Long face, high arched palette, soft skin
- Learning disabilities, cognitive efixits in inhibition, memory and planning
Turner syndrome - Chromosomal Abnormality
- chromosomal disorder in females
- One X chromosome is missing making a person with XO chromosome or a part of X chromosome is deleted
- Short in Hight, webbed neck, infertility, cognitive deficits in number processing such as mathematics
- Happens 1/2500 live female births
XYY syndrome - Chromosomal Abnormality
- Extra copy of Y chromosome is present in Males
- Early studies believed that Extra Y chromosome made males more aggressive, however that proved otherwise in recent research.
Gene-Linked Abnormalities
Abnormalities can be produced by harmful genes.
Examples - Phenylketonuria (PKU) & sickle-cell anemia
Phenylketonuria (PKU) - Gene Linked Abnormality
- Person is not able to metabolize amino acid Phenylalanine
- Accumulation of this amino acid can lead to intellectual disabilities
- This can be controlled by a diet that is not rich in phenylalanine such as peanuts, soybeans
Sickle-cell anemia
- A red blood cell is usually round and carries rich blood and oxygen to the body parts
- In Sickle Cell anemia RBC becomes sickle / hook shape and can not deliver proper amount of oxygen rich blood to body parts
- Cell dies pre maturely and body organs are affected causing early death
Prenatal Diagnostic Tests
1- Ultrasound - Use of sound waves to see growth and structural abnormalities of fetus
2 - fetal MRI -Used to detect minute structural abnormalities including including microencephaly, a form of intellectual disability involving an abnormally small brain
3 - Chorionic Villus Sampling (CVS) - 9.5 and 12.5 weeks of pregnancy / used in detect genetic defects and chromosomal abnormalities, Small part of placenta is removed for testing. May result in lib deformity
4- Amniocentesis - Examination of amniotic fluid to test chromosomal abnormalities
5. Maternal Blood Screening - 16-18 Weeks
6 - Noninvasive Prenatal Diagnosis (NIPD)
7 - Fetal Sex Determination
Maternal Blood Screening
Detects birth defects such as spina bifida (a defect in the spinal cord) and Down syndrome. birth defects such as spina bifida (a defect in the spinal cord) and Down syndrome
Noninvasive Prenatal Diagnosis (NIPD)
- alternative to procedures such as chorionic villus sampling and amniocentesis
- Small amounts of DNA traces that float in mother’s blood are collected and examined for Huntington’s disease and cystic fibrosis
Fetal Sex Determination
- Chorionic villus sampling has often been used between 11 and 13 weeks of gestation.
- Advanced imaging technology is also used to detect the sex of the fetus as early as 7th week.
- raises ethical issues about detecting disorders as this might lead to termination
Infertility
Inability to conceive a child after 12 months of regular intercourse without contraception.
IVF - (s in vitro fertilization )
eggs and sperm are combined in a laboratory dish. If any eggs are successfully fertilized, one or more of the resulting fertilized eggs is transferred into the woman’s uterus
meta-analysis
Combining the result of multiple studies to measure the strength of an effect
Reasons for diversity in adaptation of children
- Increased use of contraceptives and Legal abortions
Both factors make children less available for adaptation hence infertile couples reach-out for more diverse backgrounds where income requirements are less
ADOPTION
legal process by which a parent-child relationship is established between persons unrelated at birth
Why adaptation in early age within 12 months of age is preferred
- Better adjustment with family
- Less juvenile delinquency after growing up
- Nurturing is strong
Keys to effective parenting
- Be supportive and caring
- involve and monitor child’s whereabouts
- communicate well
- help child to develop self control
Things to remember while parenting for Adapted child
- Acknowledge differences in birth family life
- Communicate about those differences
- help the child in exploring self identity
- Show respect for birth family
Issues faced by parents in adapted children in various stages
Infancy - Attachment issue 9 Hormonal and natural
Early Childhood - “Being truthful about adaptation as child asks where I came from?
- Middle and late childhood - Children may want to explore their roots, who are there original parents, why did they leave them? this creates anger
Adolescence - adapted children develop logical thinking. Start comparing physical differences between them and adaptive parents and ask questions that might be uncomfortable
Behavior genetics
Field that seeks to discover the influence of heredity and environment on individual differences in human traits and development
What Behavior genetics tries to explore?
- To what extent either genetics or environment is responsible to develop a behavioural trait in human.
Methods used by behavior genetics for study?
1- Twin Study
2- Adapted children Vs Non adapted children study
Twin study
Behavioral similarity of identical twins (who are
genetically identical is compared with the behavioral similarity of fraternal twins
adoption study
Study that seeks out if behavioural characteristics are similar to biological parents or they are similar to adaptive parents
Issues with twin Studies
- Identical Twins may be perceived as a Set rather than non identical Twins hence parents might expose them to a similar environment.
- Identical twins due to their physiological similarities my play together and perceive themselves as same / similar
Bothe factors may create issues in separating their environment
3 Types of Heredity - Environment Correlation
1- Passive Genotype Environment Correlation
2- Evocative Genotype Environment Correlation
3 - Niche Picking Environment Correlation
passive genotype-environment correlations
Natural parents genetically related to child provide rearing environment. Example parents with higher IQ - good at reading provide good books - child develops reading habit
passive genotype-environment correlations
Child genetics induces a certain behaviour that evokes a certain response. E.g. - A smiling child receives more attention from teachers etc.
Niche Picking / Active Genotype passive genotype-environment correlations
Children seek out environments they find compatible and stimulating. E.g. Children like visiting library or music shops
How genotype-environment correlations changes as per the age
- From birth to late child hood might be passive genotype environmental. Parents provide environment.
However as the age grows children learn to take their own decisions - their behavior evolves leading to Evocative genotype and during adolescence it may turn in to niche picking genotype where they select their own environment
Shared environmental experiences
Children who grow up together in one family have common aspects such as parents intelligence, socio economic status, domestic intellectual orientation, neighborhood they grow up, common friends they have etc.
Non shared environmental experiences
child’s unique experiences, both within the family and outside the family, that are not shared with a sibling. E.g both children having different set of friends.
The Epigenetic View
Heredity and environment operate together—or collaborate—to produce a person’s intelligence, temperament, height, weight, ability to pitch a baseball, ability to read, and so on
Example of The Epigenetic View
During prenatal period mothers diet, stress etc. affect some genes. During infancy baby’s diet, environment also makes some genes weak or strong hence the genetic activity keeps on changing affecting the behaviour
Gene 3 Environment Interaction (G X E)
Interaction between specific genes and specific environment that leads to changes in behaviour. For E.g. those who have short version of 5 HTTLPR , a gene involving a neurotransmitter serotonin if interacts with a high stress environments leads to depression. Here a 5 HTTLPR did not lead to depression however a specific environment with that did
