CHAPTER 3: BIOLOGICAL BEGINNINGS

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CHAPTER 3 BIOLOGICAL BEGINNINGS

• THE EVEOLUTIONARY PERSPECTIVE

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Natural Selection and Adaptive Behavior

• Natural Selection The evolutionary process that
  favors individuals of a species that are best
  adapted to survive and reproduce Darwins On
  the Origin of Species.
• Adaptive Behavior That which promotes an
  organisms survival in its habitat (e.g, eagles
  claws), attachment in humans.

Evolutionary psychology Emphasis on the
importance of adaptation, reproduction, and
survival of the fittest in explaining behavior.
Evolution favors behaviors that promote survival.
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GENETIC FOUNDATIONS What are Genes?

• Chromosomes Threadlike structures of 23 pairs,
  one member of each pair from each parent,
  containing DNA. Each gene is a short segment
  composed of DNA acting as a blueprint for cells
  to reproduce themselves.
• Mitosis is the process where each chromosome in
  the cells nucleus duplicates itself. Meiosis is
  where each pair of chromosomes separates one
  member going to each gamete.

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Genetic Principles

• Dominant-recessive genes principle The
  explanation of gene dominance relative to hair
  color, eyesight, and freckles.
• Sex-linked genes An explanation of the XY
  chromosomal makeup that determines gender.
• Genetic imprinting The dominance of imprinted
  genes and its effect on some genetic diseases.
• Polygenic inheritance The interaction of genes,
  forming the organisms genotype and phenotype.
• Reaction range Demonstrates the importance of
  an environments positive and negative effects.
• Canalization Natures pathway to development
  thought to be a protective measure from
  environmental extremes.

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Methods Used by Behavior Genetics genetic
influence on behavior.

• Identical twins monozygotic single fertilized
  egg
• Fraternal twins dizygotic separate eggs
• Twin studies help establish hereditys effect on
  behavior.
• Adoption studies reveal more strength for the
  inherited-behavior theory.
• Molecular genetics and the categorization of
  the human gene through the Genome Project. There
  is great potential here for the control of some
  diseases.

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Chromosome and Gene-Linked Abnormalities

• Down syndrome The presence of a 47th
  chromosome, leading to a child with specific
  physical characteristics and mental limitations.
• Klinefelter syndrome A sex-linked abnormality
  found in males who have an extra X chromosome
  affecting sexual traits.
• Fragile X syndrome An abnormality in the X
  chromosome, causing mental retardation and
  learning disabilities.
• Turner syndrome Females missing an X
  chromosome, leading to possible infertility and
  some learning disabilities.
• XYY syndrome An extra Y chromosome in males,
  causing above-average height.
• Phenylketonuria Organism cannot metabolize an
  amino acid could cause mental retardation and
  hyperactivity.
• Sickle-cell anemia Most often found in African
  Americans, affecting red blood cells, causing
  anemia and possibly early death.

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Reproductive Challenges and Choices

• Amniocentesis A test by which amniotic fluid is
  withdrawn and tested for chromosomal or metabolic
  disorders.
• Ultrasound sonography Soundwaves that are
  transformed into visual representations of the
  fetus.
• Chorionic villi sampling Where a sample of the
  placenta is removed and tested for birth defects
  considered to be more dangerous than
  amniocentesis.
• Maternal blood test Used to assess blood alpha
  protein level to identify possible defects to the
  brain and spinal cord formation.
• Infertility Occurring in approximately 10 to 15
  percent of couples in the United States who
  cannot conceive a child through regular
  intercourse. Causes and results are studied.
• Adoption The effects of adoption on children
  and the challenges to adoptive parents are
  discussed.

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HEREDITY-ENVIRONMENT INTERACTIONIntelligence
What is the heredity and environmental influence
on intelligence?

• Jensen contended that environment is minimal to
  heredity a view that sparked controversy.
• The Bell Curve A book by Herrrnstein and Murray
  (1994) statistically supporting Jensens
  contention also provided controversy. The
  argument centers on the belief that IQ can or
  cannot be quantified.

Environment Scientists believe that rich
environments can raise intelligence, as is
evidence by some studies that focused on children
born of low socioeconomic status parents and
raised in high socioeconomic status environments.
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HEREDITY-ENVIRONMENT CORRELATIOINS

• Passive genotype-environment correlations
  Biological parents provide rearing environment
  for child.
• Evocative genotype-environment correlations
  Genetic foundation s elicit social and physical
  influences from the environment. (Agreeable
  children get more positive attention.)
• Active (niche-picking) genotype-environment
  correlations seeking environments that are
  found compatible to the individual.
• Shared and nonshared environmental experiences
  Childrens common genetic inheritances versus
  their unique experiences in and outside the
  family.
• Conclusions about heredity-environment
  interaction Heredity and environment operate
  together. Both environment and heredity are
  complex in their own way and both are influenced
  by the other.