Introduction to Psychology

Section 014, Fri 11:00am-12:15pm, Bobst LL139, Chloe Chan

Recitation 1-Ch 2a

Contact Information cc3930@nyu.edu Office hours by appointment

Arrange through email or in-person Location and time based on availability

Course Overview 7 hour research participation requirement

Extra credit if student completes 4 extra hours Questions? Contact Jessica Thomas (

psych.subjects@nyu.edu) Class participation (iClicker)

Attending 15 non-exam class sessions: improve final grade by an added z-score of 0.0425

Attending 19 non-exam class sessions: : improve final grade by an added z-score of 0.0850

Exams First exam: February 22nd

4 exams Best exam: weighted 1/3 of course grade Worst exam: weighted 1/6 of course grade 2 Intermediate exams: each weighted ¼ of course

grade Exams will have 2 sections: multiple choice and

essay Better section will be weighted 6/10 of exam grade Worse section will be weighted 4/10 of exam grade

How to Study Study resources

Textbook Study Guide (up to 1/3 of MC questions on exam) Handouts (essential information NOT included in

textbook) Lecture slides Recitation slides Possible essay questions (handout) MC points of focus (handout) Review sessions hosted before exam

Ch 2a- The Genetic and Evolutionary Roots of Behavior

Genetics and DNA Evolution by Natural Selection The Genetics and Evolution of Behavior Some Final Thoughts: The Strengths and the

Limits of Evolutionary Theorizing

Genetics and DNA Chromosomes: structures in the nucleus of each

cell that contain the genes, the units of hereditary transmission. A human cell has 46 chromosomes arranged in 23 pairs

DNA (deoxyribonucleic acid): The complex molecule that is the constituent of genes

Gene: A section of a DNA molecule that contains instructions for how and when to assemble a protein. Genes are located on chromosomes

Cell Nucleus Chromosome Gene DNA

Gene Expression Gene expression is controlled by the interaction

between genes and the environment (nature and nurture)

3 factors that control if or when a gene will be expressed:

(1) Environment just outside of the cell (2) State of development the organism is in (3) Organism’s overall environment and behavior

Genotype: The complete set of an organism’s genes Phenotype: The overt characteristics and behaviors of

an organism

Gene Transmission Mom: 23 pairs of

chromosomes (46 total chromosomes)

Dad: 23 pairs of chromosomes (46 total chromosomes)

Donate 1 from each pair to sex cells each egg and each sperm contains 23 chromosomes

Egg + sperm = Baby (46 chromosomes)

Interaction among Genes Genes come in pairs at

corresponding loci Homozygous: paired

genes are identical (Br-Br or Bl-Bl)

Heterozygous: paired genes are different (Br-Bl)

Interaction among Genes Allele: An alternative form of a specific gene Dominant: A term for a gene that directs the

development of a particular characteristic even when the corresponding gene on the other chromosome is different- i.e., some other allele

Recessive: A term for a gene that directs the development of a particular characteristic only if the corresponding gene on the other chromosome matches it—i.e., is the same allele

Interaction among Genes Codominant: Both genes in the pair affect the

phenotype Blood type AB

Incomplete Dominance: A person with two different alleles will have a phenotype that is intermediate between the types favored by each allele on its own Serotonin transporter gene

Polygenic inheritance: A pattern in which many genes all influence a single trait Bipolar disorder and schizophrenia

Phenylketonuria (PKU) Passed on by a single recessive gene on chromosome 12 Those with PKU produce far too little of a digestive enzyme

that breaks down phenylalanine, an amino acid Leads to build up of phenylalanine in the brain/body & mental

retardation But…PKU genotype may or may not lead to the PKU

phenotype (mental retardation) PKU can be tested at birth!

Child put on strict diet without phenylalanine develop normally Environmental factors (diet) can influence person’s phenotype

Evolution by Natural Selection Proximate cause: The influences within an

organism’s lifetime that led to its particular traits or behaviors

Ultimate cause: The reasons why, over many years of evolution, a particular trait or behavior helped members of a population to survive and reproduce

Darwin’s Two Great Ideas The descent of all life comes from a

common origin Came from his observations of different

finch species in the Galapagos islands Evolution occurs through Natural Selection

Individuals with the advantageous trait are more likely to survive, reproduce, and pass on these traits to offspring

Individuals with the disadvantageous are more likely will die, meaning they will reproduce less, and the trait will not be passed on to offspring

Evolution by Natural Selection Natural Selection: The mechanism that drives

biological evolution. It refers to the greater likelihood of successful reproduction for organisms whose attributes are advantageous in a given environment

Naturalistic Fallacy: The (mistaken) idea that anything “natural” must be “good”

Three Principles of Natural Selection

(1) There must be variation among the individuals within a population

(2) Certain of the variants must survive and reproduce at higher rates than the others

(3) The traits associated with this superior survival and reproduction must be passed from parents to offspring

Variation among individuals arises from: Random selection of chromosomes during sexual

reproduction Mutations: Errors in the replication of DNA

Genes and Evolution “Survival of the Fittest”?

Not personal survival, but species/ gene survival

Reproduce and pass genes to next generation

Examples of these principles: Piping plover Belding’s ground squirrel

Piping Plover Example When a predator approaches nest, mother bird flies away and

feigns injury She appears as an easy target in order to draw in the

predator and distract them from her offspring This behavior puts the mother bird at substantial risk!

Genes favoring a self-protective response would make the mother more likely to survive, but less likely to contribute copies of those genes to future generations Genes promoting self-protection would become less

common in the population. Natural selection favors the protective mother (and genes that

promote protective behavior) protective behavior becomes the dominant trait in the

population

Evidence for Evolution by Natural Selection

Selective breeding New breeds of farm animals and crops

Fossil Record Intermediate organisms

Anatomical leftovers Remnant hip and leg bones (whales), tailbone (humans)

Molecular structure of genome Pattern of relatedness

Process of evolution in present-day populations Threespine stickleback

Threespine Stickleback Example Water went from murky to clear in Lake

Washington Fish with more armor more likely to survive and

pass trait onto offspring Low-plated fish dropped from 91% in 1957 to

16% in 2005 Evidence of Natural Selection!

The Unity of Life Because of our shared ancestry, we have much in

common with other species we can learn a lot about ourselves from studying them

Translate animal research results to learn about humans!

Evidence in support of a common ancestor: Birds & crocodiles Whales & even-toed, hoofed animals (hippos) Crystal jellyfish’s green fluorescent protein in rhesus

monkeys Humans’ hLhx2 gene in fruit flies

The Genetics and Evolution of Behavior

Evolution favors flexibility and learning rather than rigidly defined behaviors

Niche construction: The process in which organisms, through their own behaviors, alter the environment and create their own circumstances

Niche: All of the factors in an organism’s environment that have the potential to affect its life

Study guide MC Questions 2) Which of the following statements is FALSE?

(a) A cell has a nucleus containing 46 chromosomes (b) Chromosomes carry instruction for how to build

and operate a body (c) Each chromosome is made of a single, long,

coiled strand of DNA (d) The DNA molecule has a double helix shape (e) The rungs of the helix are made up of

complementary chains of adenine (A) paired with guanine (G) and cytosine (C) paired with thymine (T)

Study guide MC Questions 14) Studies have indicated that people who

produce less of a serotonin transporter are at greater risk for both depression and anxiety and may react differently to antidepressant medication. The genetics that control the amount of transporter are examples of (a) dominance (b) incomplete dominance (c) polygenic inheritance (d) two of the above (e) none of the above

Study guide MC Questions 15) The reasons why, over many years of

evolution, a particular trait or behavior would have helped members of a population to survive and reproduce is termed its ____causes. (a) phenotypic (b) ultimate (c) proximate (d) genomic (e) two of the above

Study guide MC Questions 28) For behaviors just as for physical traits, what does

evolution NOT require for advantageous behavioral traits to come to characterize an entire species? (a) variation among individuals on some relevant behavioral

characteristic (b) a higher rate of reproductive success for individuals with

some of the variations (c) increased personal survival beyond the age for reproducing

and promoting the survival of offspring or their children (d) continued conditions in the environment favorable over

several generations to the passing of the successful variations from parents to offspring

(e) none of the above