The Evolutionary Perspective

• Focuses primarily on psychological adaptations - mechanisms of the mind that have evolved to solve specific problems of survival or reproduction

• Natural selection and adaptive behavior

• Evolutionary psychology

Natural Selection & Adaptive Behavior

• Natural Selection: Evolutionary process by which those individuals of a species that are best adapted are the ones that survive and reproduce and leave the most fit offspring

• DISCLAIMER - this theory is just a possible explanation of development. It’s not a end all be all

  • Their characteristics are passed on to the next generations through reproduction

  • Over generations, those best suited for survival will make up an increased percentage of the population

• Adaptive behavior: behavior that promotes an organism’s survival in its natural habitat

  • Example: a close attachment between a caregiver and a baby increases the infants chances of survival.

Evolutionary Psychology

• The field of evolutionary psychology emphasizes the importance of adaptation, reproduction, and “survival of the fittest” in shaping behavior.

  • maybe survival of the fittest

• David Buss argues that just as evolution has contributed to our physical features, it also influences psychological features such as:

  • How we make decisions, how aggressive we are, our fears, and our mating patterns.

Evaluation of Evolutionary Psychology

• Evolution gave us biological potentials, but it does not dictate behavior

• Evolutionary selection benefits decrease as we age, and a need for culture-based resources increase.

  • E.g., cognitive skills, literacy, medical technology, and social support

Genetic Foundations of Development

• The collaborative gene

• Genes and chromosomes

• Genetic principles

• Chromosomal and gene-linked abnormalities

The Collaborative Gene

• The potential for human life begins as a single cell

• Nucleus of each cell contains chromosomes - threadlike structures made up of DNA

  • DNA is a complex double-helix molecule that contains genetic information

• Genes are units of hereditary information; short segments of DNA

  • Humans have about 30,000 genes

Genes and Chromosomes

• All cells in the body, except the sperm and egg, have 46 chromosomes arranged in 23 pairs

  • These cells reproduce through mitosis - cell division process that produces 2 identical “daughter” cells from a single “parent” cell, containing the same DNA as the original cell.

  • Meiosis - the process of cell division that forms sperm and eggs - produces cells that are genetically unique from the “parent” cell and contain only half as much DNA

• Fertilization is a stage in reproduction when an egg and a sperm fuse to create a single cell, called a zygote.

  • Combining the genes of two parents in offspring increases genetic variability in the population

  • This is valuable as it provides more characteristics for natural selection

• Genotype genetic heretige

• Phenotype - the way genotype is expressed in observable and measurable characteristics

Twins

• Monozygotic twins

  • Identical

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

• Dizygotic twins

  • Fraternal

  • Develop when two eggs are fertilized by different sperm, creating two zygotes that are genetically no more similar than ordinary siblings

Genetic Principles

• Genes are either dominant or recessive, or intermediate

  • Examples: eye color

• A dominant gene shows a strong effect in whether the homozygous or heterozygous condition

  • Brown eyes are more likely to occur in any type of gene

• A recessive gene shows its effect only in the homozygous condition

  • Blue eyes will only occur if the gene was heterozygous (both parents had blue eye gene)

• An intermediate gene occurs in a phenotype where there is incomplete dominance in the heterozygous condition

  • Green or hazel eyes are produced when the dominant color (brown) was incomplete

  • MY DAD WITH HIS GREEN EYES

Chromosomal Abnormalities

Reproductive challenges and choices

• Prenatal diagnostic tests

• Infertility and reproductive technology

Prenatal DIagnostic tests

Infertility and Reproductive technology

• Approximatley 10-15% of couples in the US and 8-12% globally experience infertility

  • The inability to conceive a child after 12 months of regular intercourse without contraception

  • Can be due to genetic or environmental factors

• In vitro fertilization (IVF) - eggs and sperm are combined in a laboratory dish; once fertilized, the egg is transferred into the uterus.

Heredity-Environment Interaction

• Behavior genetics is the field that seeks to discover the influence of heredity and environment on individual differences in human traits and development.

  • Nature vs nurture debate - what influences human behavior? Genetics or the environment and their life experiences?

• Researchers tend to study:

  • Twin studies have compared the behavioral similarity of identical and fraternal twins to infer contributions of hereity and environment

  • Adopted children and their resemblance to their biological parents, to infer hereditary influences

  • Identify if specific genes are linked to some behaviors