Biological Beginnings

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Biological Beginnings

• Lecture 3
• C6035 Human Development

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Evolutionary Perspective Natural Selection
Adaptive Behavior

• Natural selection is evolutionary process
  favoring individuals of a species best adapted to
  survive reproduce
• Adaptive behavior promotes organisms survival in
  natural habitat

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Race and Ethnicity

• Race is a biological concept referring to a
  system for classification of plants animals
  according to physical structural
  characteristics
• Ethnicity is a sociocultural concept reflecting
  religion, heritage language

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Heredity and Reproduction

• Genes are a blueprint for cells to reproduce
  themselves manufacture proteins that maintain
  life
• Chromosomes - Comprises content of living cells
  in 23 pairs of threadlike structures
• DNA - A molecule containing genetic information
  in shape of a double helix which make up genes

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Reproduction

• Process by which an organism transmits
  characteristics from one generation to next
• Gametes reproductive cells created in testes of
  male and ovaries of female
• Meiosis process of cell doubling separation of
  chromosomes
• Reproduction process that begins when female
  gamete is fertilized by male gamete
• Zygote formed through fertilization process.

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Abnormalities in Genes and Chromosomes

• Phenylketonuria (PKU) genetic disorder where
  individual cannot metabolize amino acid can
  result in mental retardation hyperactivity
• Down Syndrome genetically transmitted form of
  mental retardation caused by presence of an extra
  (47th) chromosome
• Sickle-cell Anemia occurs mostly in people of
  African descent affecting red blood cells.

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Abnormalities in Genes and Chromosomes

• Klinefelter Syndrome in which males have an extra
  X chromosome to form XXY instead of XY
• Turner Syndrome in which females are missing an X
  chromosome to form XO instead of XX.
• XYY Syndrome where males have an extra Y
  chromosome was once believed to be cause of
  violence in men who possessed XYY composition.
  Abnormalities in Genes and Chromosomes, modern
  research dispelled this belief

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Prenatal Procedure Tests To Determine
Abnormalities

• Amniocentesis amniotic fluid drawn by syringe
  tested for chromosomal or metabolic disorders
• Ultrasound Sonography using high-frequency sound
  waves to attain visual representation of fetus
  inner structures.
• Chorionic Villus Test small sample of placenta
  removed to determine whether or not abortion is
  safe near end of first trimester
• Maternal Blood Test diagnostic technique to
  assess blood alpha protein levels associated with
  neural-tube defects

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Genetic Principles, Methods Influences

• General Principles Dominant-recessive Genes
  Principle - is higher influence of the dominant
  gene over the recessive except where recessive is
  present in two genes of a pair

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• Polygenic Inheritance influence of many genes
  interacting to produce particular characteristic
• Genotype persons genetic heritage, actual
  genetic material
• Phenotype way an individuals genotype is
  expressed in observable measurable
  characteristics
• Reaction Range range of possible phenotypes for
  each genotype which demonstrates importance of
  environment
• Canalization developmental course taken by
  certain characteristics presumably as protection
  for reaction to environment

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Methods Used By Behavior Geneticists

• Behavior Genetics study of degree nature of
  behaviors hereditary basis
• Twin Study behavioral similarity of identical
  twins is compared with that of fraternal twins
• Fraternal Twins dizygotic, twins develop from a
  separate sperm and separate egg
• Identical Twins monozygotic, twins develop from
  single fertilized egg that splits into two
  genetically identical replicas
• Adoption Study compare development of adopted
  children with that of biologically reared
  children to note differences between nature
  nurture

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Hereditys Influence on Development

• Study of hereditys influence on development
  generally centers around intelligence
  temperament of an individual studying impact of
  genetics on intelligence has produced most
  controversy
• Arthur Jensen claims that culture environment
  have minimal effect on intelligence
• Murry and Hernsteins bell curve theory predicts
  growth of an underclass of intellectually
  deprived individuals

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Heredity-Environment Interaction
-Genotype-Environment Concepts

• Behavior geneticists believe that heredity
  environment interact
• Passive Genotype-Environment Interactions occur
  when parents who are genetically related to child
  provide a rearing environment for child
• Evocative Genotype-Environment Interactions occur
  because childs genotype elicits certain types of
  physical social environments
• Active (niche-picking) Genotype-Environment
  Interactions occur when children seek out
  environments compatible stimulating

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Shared and Nonshared-Environment Influences

• Some theorists believe that environments role in
  heredity-environment interaction can be carved up
  to consider experiences of children that are in
  common with those of other children living in the
  same home, as well as experiences that are not
  shared
• Shared Environmental Influences childrens common
  experiences such as their parents personalities
  intellectual orientation.
• Nonshared Environmental Influences childs unique
  experiences that are not shared with another
  sibling.

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Nature and nurture operate together

• They cooperate - to produce a persons
  intelligence, temperament, height, weight,
  ability to pitch a baseball, reading skills, etc
• Conclusions About Heredity-Environment Interaction