BIOLOGICAL BEGINNINGS

Natural Selection

Evolutionary Process by which those individuals of a species that are best adapted are the ones that survive and leave th emost fit offsprings.

Evolutionary Psychology

Emphasizes the impotance of adaptation, reproduction, and “survival of the fittest” in shaping behaviors

Chromosomes

Threadlike structures made up of deoxyribonucleic acid (DNA)

DNA

Complez 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. Helping cells to reproduce themselves and tomanufacture the proteins that maintain life.

Proteins

The building blocks of cells as well as the regulators that direct the body’s processes.

Methylation

Tiny atoms attached themselves to the outside of a gene. This process makes the gene more or less cpable of recieveing and responding to biochemical signals from the body.

Mitosis

Cellular reporduction in whic the call’s nucleus duplicates itself with two new new cells being fromed, each containnh the sme DNA as the parent cell, arranged in the same 23 pairs of chromosomes.

Meiosis

A specialized form of cell division that occurs to form eggs and sperm

Gametes

Sex cells such as eggs and sperm.

Fertilization

A stage in reproduction when an egg and a sperm fuse to create a single cell, called Zygote.

Zygote

A single cell formed through fertilization. The 23 unpaired chromosomes from the egg and the 23 unpaired chromosomes from the sperm combine to form one set of 23 paired chromosomes.

Monozygotic Twins

Develops from a single zygote that splits into two genetically identical replicas, each of which becomes a person.

Dizygotic Twins

It happens when two eggs are fertilized by different sperm, creating two zygotes that are genetically no more similar than ordinary siblings.

Susceptibility Genes

They make individuals more vulnerable to specific disease or accelerated aging.

Longevity Genes

They make individuals ls vulnerable to certain diseases and more likely to live an older age.

Genotype

A person’s genetic Heritage; The actual genetic material.

Phenotype

The way an indivudal’s genotype is expressed in observed and measurable characteristics.

The process of genotype to phenotype

DNA first become RNA (Ribonucleic Acid), which inture is translated into amino acids thatw ill become proteins. Then, they become capable of producing phenotype traits and characteristics. Also, do not forget that environments interact with genotypes to produce phenotypes.

The principle of Dominant Recessive Genes

A principle stating that if one gene of a pair is dominant and the other is recessive, the dominant gene will override the expression of the recessive gene. The recessive trait only appears if both genes in the pair are recessive.

Dominant Gene

A gene that always shows its trait in a person even if only one copy is present. It can mask the effect of a recessive gene.

Recessive Gene

A gene that only shows its trait when both copies in a pair are recessive. It is hidden if a dominant gene is present.

The Principle of Sex-Linked Gene

A genetic principle where certain traits or disorders are passed through genes located on the sex chromosomes—usually the X chromosome. Since males have only one X chromosome, a single mutated gene on it can cause a disorder. Females have two X chromosomes, so they often carry the gene without showing symptoms.

X-linked Inheritance

The result of a mutated gene that is carried on the X chromosome.

The Principle of Genetic Imprinting

A phenomenon where the effect of a gene depends on whether it was inherited from the mother or the father. Through a chemical process, one copy of the gene is "silenced," meaning only the other copy is active.

The principle of Polygenic Inheritance

A pattern of inheritance where multiple genes—not just one or two—contribute to a single trait.

Gene-gene Interaction

Refers to how two or more genes work together to influence a person's traits, behaviors, or disease risks.

Down Syndrome

A form of intellectual disability caused by the presence of an extra copy of chromosome 21. Also known as “Trisomy 21.” (Chromosomal Abnormality)

It is characterized by round face, a flattened skull, an extra fold of skin over the eyelids, a potruding tounge, short limbs, and impaired motor and mental abilities.

Klinefelter Syndrome

A chromosomal disorder in which males have an extra X Chromosome, making them XXY insted of XY.

Males with this disorder hace underdeveloped testes, and they usually have enlarged breqasts and become tall.

Fragile X syndrome (FXS)

A genetic disorder that results from an abnormality in the X-chromosome, which becomes constricted and often breaks.

Intellectual difficulty is an outcome which may take the form of an intellctual disability, autism, a learning disability, or a short attnetion span.

Turner Syndrome

A chromosomal disorder in femals in which either an X chromosome is missing, making the person XO instead of XX, or part of one X xhromosome is deleted.

Females with turner syndrome are short in stature and have a webbed neck. They might be infertile and have difficulty in mathematics, BUT their verbal ability is often quite good.

XYY Syndrome

A chromosomal disorder in which a male has an extra Y chromosome.

It can cause above avrage height. The extra Y chromosome contributes to aggression and violence. But they are no more likely to be more agressive than normal XY Males.

Phenylketonuria (PKU)

A genetic disorder in which an individual cannot properly metabolize an amino acid called phenylalanine.

If left untreated, it results i intellectual disability and hyperactivity.

Sickle-cell Anemia

A recessive genetic blood disorder where red blood cells become sickle-shaped, reducing their oxygen-carrying capacity. Causes pain, joint swelling, and risks of heart and kidney failure.

Cystic Fibrosis

A genetic glandular disorder that interferes with mucus production, leading to thick, sticky mucus that clogs the lungs and digestive system.Leading to breathing and digestion problems; can result in chronic lung infections and malnutrition.

Diabetes

A condition where the body does not produce enough insulin, a hormone needed to regulate blood sugar. It causes abnormal sugar metabolism, fatigue, excessive thirst, and potential organ damage if unmanaged.

Hemophilia

A genetic blood disorder, often X-linked, where blood doesn't clot properly due to missing or defective clotting factors. It Causes prolonged internal and external bleeding, which can be life-threatening.

Huntington’s Disease

A dominant genetic disorder that causes progressive degeneration of the central nervous system. It causes muscle coordination problems, cognitive decline, and mental deterioration. Usually appears after age 35, with death occurring 10–20 years after symptom onset.

Spina Bifida

A neural tube defect that occurs during early fetal development, leading to incomplete closure of the spine and brain structures. It may cause paralysis, bladder issues, and learning disabilities, depending on severity.

Tay-Sachs Disease

A genetic disorder caused by the absence of an enzyme needed to break down fatty substances in the brain and spinal cord. Leads to a buildup of lipids, causing mental and physical deterioration, seizures, blindness, and death.

Ultrasound Sonography

It is conducted seven weeks into a pregnanncy and at various times later in pregnancy. It is a prenated medical procedure in which high frequency sound waves are directed into the pregnant woman’s abdomen.

It detects many abnormalities in the fetus, including micorcephaly, can determine number of fetuses and give clues to the baby’s sex.

Brain-Imaging Techniques

Use of fetal MRI to diagnose fetal malformations. It may be able to detect better than ultrasound sonography on certain abnormalities of the central nervous system, chest,gastrointestinal tract, genital/urinary organs, and placenta.

Chorionic Villus Sampling

A prenatal medical procedure in which a small sample of the placenta is removed. Used to detect genetic defects and chromosomal abnormalities such as those discussed in the previous section (between 10th and 12th weeks of pregnancy).

Amniocentesis

A prenatal medical procedure in which a sample of amnioticfluid is withdrawn by syringe and tested for chromosomal or metabolic disorders (During 15th to 19th weeks of pregnancy).

In Vitro Fertilization (IVF)

Eggs and sperm are combined in alaboratory dish. If any eggs are successfully fertilized, one or more of theresulting zygotes is transferred into the woman’s uterus.

Twin Study

A study in which the behavioral similarity of identical twins is compared with behavioral similarity of fraternal twins.

Adoption Study

A study in which investigatorsseek to discover whether, in behavior andpsychological characteristics, adoptedchildren are more like their adoptive parents,who provided a home environment, or morelike their biological parents, who contributedtheir heredity. Another form of the adoptionstudy compares adoptive and biologicalsiblings.

Passive genotype-environment correlations

Correlations that exist when the natural parents, who are genetically related to thechild, provide a rearing environment for thechild.

Evocative Genotype-Environment Correlations

Correlations that exist when the child’s genetically influenced characteristics elicit certain types of environments.

Ative Genotype-Environtment Correlations

Correlations that exist whenchildren seek out environments they findcompatible and stimulating.

Niche-Picking

Finding of a setting that is suited to one’s genetically influenced abilities.

Epigenetic View

It states that development reflects an ongoing, bidirectional interchange between heredity and the environment.

Behavior Genetics

The field that seeks to discover the influence of heredity andenvironment on individual differences inhuman traits and development