SAR HP 252 Chapter Notes - Chapter 2: Human Genome Project, Evolutionism, Mitosis
2 May 2018
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CHAPTER 2: BIOLOGICAL BEGINNINGS
Natural Selection and Adaptive Behavior
• Natural Selection – evolutionary process by which individuals of a species that are best
adapted are most likely to survive and reproduce
o Created by naturalist Charles Darwin
o Essentially states that the best-adapted individuals win the fight over natural
resources and eventually survive long enough to reproduce
Evolutionary Psychology
• Evolutionary Psychology – emphasizes the importance of adaption, reproduction and
“survival of the fittest” when shaping behavior
o In this, natural selection favors behaviors that increase reproductive success in
passing genes to the next generation
• Evolutionary Developmental Psychology – using the concepts of evolutionary
psychology to understand human development
o A majority of our evolved psychological mechanisms are domain-specific,
meaning that mechanisms learned apply to specific aspects of an individual’s
psychological makeup
o Essentially meaning that as tasks were repeated, specific modules were developed
to accomplish these tasks
• Connecting Evolution and Life-Span Development
o Question: why do humans live so long after reproduction?
o Some believe that the benefits from evolutionary selection decrease with age
▪ ex: harmful conditions, nonadoptive characteristics, disease
• Evaluating Evolutionary Psychology
o One-Sided Evolutionism – views social behavior as the strict product of evolved
biology
▪ This is not true
o Rather, evolution gives us biological potentialities but it does not dictate behavior
o Diverse cultures are all around us that stem from similar biological capacities
o Thus the best way to study evolutionary psychology is to study specific genes and
their links to traits/behaviors
The Collaborative Gene
• Genetic influences on behavior have evolved
• DNA – inherited from our parents as well as other species that were once our ancestors
• Chromosomes – structures made up of DNA
• DNA – a complex molecule shaped like a double helix containing genetic information
• Genes – units of hereditary information that are constructed as short segments of DNA
• Genes help cells reproduce and ultimately assemble proteins to help regulate the body
• Human Genome Project – locate genes in the body (as each has specific locations)
• Genome-Wide Association Method – used to identify genetic variations linked to
particular diseases
find more resources at oneclass.com
find more resources at oneclass.com
o Done by comparing health and unhealthy DNA and pinpointing the locations
where genetic variations occur and analyzing those sections of the human genome
• Gene activity is affected externally (environmental) and internally (cells)
Genes and Chromosomes
• Genes are enduring
• Mitosis, Meiosis and Fertilization
• All cells have 46 chromosomes arranged in 23 pairs
• Mitosis – a cell division process meant to reproduce cells
o Results in two new and identical cells
o Each contains the same DNA as the original cell
• Meiosis – a cell division process meant to reproduce specifically sex cells (eggs and
sperm)
o Results in four new and not necessarily identical cells
o Each contains half the DNA as the original cell
• Fertilization – when an egg and sperm fuse to create a single cell
• Zygote – a single cell formed during fertilization
o Combines the 23 chromosomes from each sex cell to create a cell with 46
chromosomes and half of each parent’s genetic material
▪ Female 23rd Chromosome: XX
▪ Male 23rd Chromosome: XY
• Sources of Variability – combining genes from two parents increases genetic variability
within the population and ultimately the selection of characteristics for natural selection
o Chromosomes in the zygote are not exact copies of their parents
▪ Question: how are identical twins formed?
▪ Answer: a single zygote splits into two genetically identical replicas
o DNA Mutations – errors in DNA replication that affect genes
• Genotype – an individual’s genetic material
• Phenotype – an individual’s physical characteristics (essentially how the genotype is
expressed and observed)
Genetic Principles
• Dominant Genes v. Recessive Genes
o Dominant (capital letters) – the gene that dominants over the other
o Recessive (lowercase letters) – the gene that is often unseen because it is
dominated over
o Options: DD, Dd, dd
• Sex-Linked Genes – most mutated genes are recessive
• X-Linked Inheritance – when a mutated gene is carried on the X chromosome
• X-Linked Disease – inheritance of a mutated gene on the X chromosome in males which
makes them susceptible to developing disease (as they only have one X chromosome)
o Carriers – females who have an X-Linked Disease but do not show any symptoms
because they have two X chromosomes
• Genetic Imprinting – when the expression of a gene has different effects depending on
whether the mother/father passed on the gene
find more resources at oneclass.com
find more resources at oneclass.com
