PSYCH 1100 TEST 3 NOTES- GRAY AND BJORKLUND

What theory did Charles Darwin propose over 150 years ago?

Darwin's theory of evolution, explaining the similarities and differences between species.

How is DNA related to genes?

Genes are parts of DNA that give instructions to make proteins.

What are the main types of proteins made from genes?

• Structural proteins

• Enzymes

• DNA

What is DNA made of, and what does it do?

DNA is made of building blocks called amino acids and helps make RNA, which makes proteins.

What are the two main types of genes?

• Coding Genes: Templates for RNA to create proteins.

• Regulatory Genes: Control the activity of coding genes, previously called "junk DNA."

How do genes work with the environment?

Genes and the environment affect each other all the time. The environment influences how genes work.

How many genes are in the human genome?

There are 20,000 to 25,000 genes in the human genome.

How small genetic differences can make a big impact?

• A 0.001% difference: DNA doesn’t match at a crime scene or for paternity.

• A 0.5 to 4% difference: You may be closely related to a chimpanzee.

• A 50% difference: You may share DNA with a banana.

What is the genome?

The genome is an organism’s complete set of genes.

How do genes work?

Genes help build proteins for the body and can be turned on/off by the environment or other genes. Traits result from complex interactions between genes and other molecules.

What’s the difference between genotype and phenotype?

• Genotype: The genes you inherit.

• Phenotype: The traits you show (like eye color), which are influenced by both your genes and the environment.

Why can identical twins have different phenotypes?

Even though identical twins have the same genotype, differences can happen due to factors like different positions in the womb, affecting nutrition and gene activation.

How are genes passed along through reproduction?

DNA is in chromosomes. Humans have 23 chromosome pairs—22 are the same for everyone, and the last pair determines sex (XX for females, XY for males). One chromosome from each pair comes from each parent.

What is the difference between mitosis and meiosis?

• Mitosis: Cells divide to make identical copies.

• Meiosis: Reproductive cells divide to make non-identical cells.

Why is genetic diversity important?

Genetic diversity increases the chances of genes surviving through each generation.

What are identical and fraternal twins?

• Identical twins: Have the same genes.

• Fraternal twins: Are like regular siblings with different genes.

What is Mendelian heredity?

• Dominant genes: Show their effects in both homozygous and heterozygous conditions.

• Recessive genes: Only show their effects in homozygous condition.

Can a single gene affect behavior?

Yes, some behaviors are controlled by a single gene, like fearfulness in dogs or a language disorder in the KE family.

What is selective breeding?

Selective breeding is when animals are bred for specific traits, like maze learning in rats, to study how heredity affects behavior.

What is epigenetics?

Epigenetics studies how gene activity can change without altering the DNA code and how these changes can be passed down.

What is DNA methylation?

DNA methylation is the best-understood way epigenetics affects gene activity and can influence behavior across generations.

How do twin and adoption studies help understand genetics?

They compare traits in siblings and identical twins to see how genes affect behavior in the same environment.

What’s the difference between fraternal and identical twins?

• Identical twins: Are the same sex.

• Fraternal twins: Can be the same or opposite sex.

What are critiques of twin studies?

• Twins may influence each other if they know about each other.

• Coincidences can make strangers seem very similar.

• Adoptive families may have similar environments like biological ones.

What similarities were found in identical twins raised apart?

even raised apart, identical twins show similarities in personality, intelligence, attitudes, interests, and even brain activity.

Why are siblings so different?

Siblings share half their genes, but genetic differences grow as they react to these differences. They also grow up in slightly different families (older siblings, different parents).

What is temperament, and how does it differ between people?

Temperament is a person’s emotional reactivity. It stays mostly the same from infancy to adulthood, and people can be:

• Easy

• Difficult

• Slow to warm up

Do adopted children resemble their genetic relatives or their adoptive relatives more?

Adopted children tend to be more similar to their genetic relatives than their adoptive ones.

What does parenting influence?

Parenting affects:

• Religious beliefs

• Values

• Manners

• Attitudes

• Politics

• Habits

How do genes and the environment interact?

• Self-regulation: Genes turn on/off based on the environment.

• Epigenetics: The environment changes gene activity, like stress affecting cortisol levels.

How does the environment influence genes?

Examples:

• Shortened daylight changes animal fur color or triggers hibernation.

• Obesity in adults can turn off weight-regulating genes in their kids.

What is the difference between genetics and epigenetics?

Genetics determines our DNA, while epigenetics refers to how environmental factors change gene activity (like stress or diet).

What is evolution by natural selection?

Darwin's theory says that individuals with traits that help them survive and reproduce are more likely to pass those traits to the next generation.

What are the core concepts of natural selection?

• Overproduction of offspring.

• Variation in traits within a generation.

• Inherited differences.

• Traits that fit the environment increase survival and reproduction.

What are the sources of genetic variability for natural selection?

• Reshuffling of genes during reproduction.

• Mutations (random errors in DNA copying).

Does evolution have foresight?

No, evolution doesn’t work toward a set goal. It’s influenced by environmental changes that lead to mutations and natural selection.

Are humans the "most evolved" species?

No, humans are not the most evolved species, and natural selection is not a moral force.

What is functionalism in the context of behavior?

Functionalism tries to explain behavior by looking at how it helps the individual survive and reproduce.

What are distal and proximate explanations?

• Distal explanations: Look at behavior from an evolutionary (long-term) perspective.

• Proximate explanations: Focus on immediate, current conditions that cause behavior.

What are some limitations of functionalistic thinking?

• Some traits are vestigial (no longer serve a function), like the appendix.

• Some traits are side effects of other traits.

• Some traits result from chance.

• Evolved traits don’t always work perfectly in every situation.

Why is mating important in evolution?

Mating drives evolution by allowing species to reproduce and pass on traits.

What are the four classes of mating arrangements?

Human mating is mostly monogamous (one partner) and partly polygamous (multiple partners).

What is parental investment?

Parental investment is the time, energy, and risks involved in producing and caring for offspring.

What does Trivers' theory about parental investment suggest?

The sex that invests more in offspring (usually females) will be more selective and competed for when choosing mates.

What are different mating patterns based on parental investment?

• Polygyny: Males invest less, so they have many mates.

• Polyandry: Females invest less, so they have multiple mates.

• Monogamy: Both sexes invest equally.

• Promiscuity: Investment is in the group rather than individuals.

What is the difference between cooperation and altruism?

• Cooperation: Helping others while benefiting yourself (like wolves hunting together).

• Altruism: Helping others at a cost to yourself.

How do kin selection and reciprocity explain altruism?

• Kin Selection: You help relatives because they share your genes.

• Reciprocity: Helping others with the expectation of future help in return.