Module 5 Genetic Influences on Behavior

JONATHAN C. LEE

AP PSYCHOLOGY

Charles Darwin First evolutionary psychologist. Think of deep time. Spans in millions of years.

Creationism vs. Evolution

Challenges of Evolution

Why does change take place?

How do new species emerge?

What are the functions of parts?

Think about it: You came from a long line of ancestors, if your ancestors from a million years ago did not reproduce, you would not exist today!

1A. Explained change over time: descent with modification.

2A. Explained the apparent purpose quality of component parts: adaptive function.

3A. United all species into one grand tree of descent: including humans.

Does our genes determine our behavior?

Chromosomes: Threadlike structures made of DNA molecules contain the genes.

DNA: (deoxyribonucleic acid) a complex molecule containing the genetic information that makes up the chromosomes.

Genes: The biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing protein.

Genome: The complete instructions for making an organism, consisting of all the genetic material in its chromosomes.

Going into our Biological Blueprint

Each human has 23 chromosomes from the mother and 23 (egg) chromosomes from the father (sperm) for a total of 46 chromosomes.

There are about 30,000 genes in each of us.

Each gene has 4 alphabet of life (A,T,C, G), composed of nucleotides.

The smallest human chromosome Y has 50 million nucleotide letters and the largest has 250 million nucleotide letters.

Collectively there are about 3.1 billion paired nucleotides that define the genes that you carry.

*ATCG =   adenine-thymine, cytosine-guanine

Human traits are influenced by gene complexes – many genes acting in concert

Human genome researchers have discovered the common sequence of the 3.1 billion letters within the human DNA.

How do we use natural selection to explain behavioral tendencies?

Belayev worked with 30 male and 100 female foxes. 40 years they bred the fox to become extremely docile and well-behaved.

Belyaev demonstrated when certain traits are selected, those traits over time, can prevail.

Is it ethical to pick traits of your unborn fetus (i.e. blue eyes)?

Natural selection: the principle that, among the range of inherited trait variations, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations.

Mutations: a random error in gene replication that leads to a change in the sequence of nucelotides; the source of all genetic diversity.

Evolutionary Psychology

Questions to consider

Come up with answers in your group in the next five minutes.

P. 101

Sexuality

What do you think about this statement: Men pair widely but women pair wisely? (p. 103)

Gender: in psychology, the characteristics, whether biologically or socially influenced, by which people define male and female.

Twins

Identical twins: twins who develop from a single fertilized egg that splits into two, creating two genetically identical organisms.

Fraternal twins: twins who develop from separate eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment. Raise your hands if you are a fraternal twin!!

Temperament & Heritability

Temperament: A person’s characteristic emotional reactivity and intensity.

Heritability: the proportion of variation among individuals that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied.

Criticisms of Evolutionary Psychology

People are not “hard-wired”

Excluded cultural factors and environmental factors that also makes us human.

Challenges Judeo-Christian beliefs