Genetics and Evolution of Behavior

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Questions and Answers

What did Gregor Mendel's work reveal about the units of heredity?

They are mixed together like paint

They are only active in one sex

They are only found on sex chromosomes

They maintain their structural identity from one generation to another (correct)

What is the main difference between sex-linked genes and autosomal genes?

Sex-linked genes are found on sex chromosomes, autosomal genes are not (correct)

Autosomal genes are only found on the Y chromosome

Autosomal genes are only active in one sex

Sex-linked genes are only found on the X chromosome

What type of genetic change results in a different amino acid in a protein?

Deletion

Epigenetic change

Mutation (correct)

Duplication

What is the term for the study of heritable changes in gene expression that do not involve a change in DNA sequence?

Epigenetics Signup and view all the answers

How is heritability typically determined?

By comparing monozygotic twins and dizygotic twins Signup and view all the answers

What is an example of an environmental modification that can affect a highly heritable trait?

Phenylketonuria (PKU) Signup and view all the answers

How do genes influence behavior, according to the text?

By influencing physical attractiveness, which in turn affects social interactions Signup and view all the answers

What is the term for the change in species over generations?

Evolution Signup and view all the answers

What is the main reason for genetic influences in evolution?

Individuals with desired traits producing more offspring Signup and view all the answers

What is the main flaw in Lamarck's theory of evolution?

It suggests that acquired traits can be passed on Signup and view all the answers

Why is the idea that modern medicine slows down or stops evolution incorrect?

Because evolution is based on survival, not reproduction Signup and view all the answers

What is the correct understanding of the term 'evolution'?

It means increasing an individual's fitness Signup and view all the answers

What is an example of an altruistic behavior in animals?

A crow calling out to attract other crows for protection Signup and view all the answers

What is the term for selecting genes that benefit an individual's relatives?

Kin selection Signup and view all the answers

What is the term for expecting help in return for altruistic behavior?

Reciprocal altruism Signup and view all the answers

What is the term for the process of evolution at the group level?

Group selection Signup and view all the answers

Study Notes

Mendelian Genetics

Prior to Mendel, the understanding of heredity was like mixing two colors of paint.
Mendel introduced the concept of genes as units of heredity that maintain their structural identity from one generation to another.
Key terms: chromosomes, DNA, RNA, homozygous, heterozygous, dominant gene, recessive gene.

Sex-Linked and Sex-Limited Genes

Sex-linked genes are located on the X and Y chromosomes (sex chromosomes in mammals).
Autosomal genes are located on all other chromosomes.
Sex-limited genes are active in both sexes but more prominent in one sex (e.g., chest hair in men, breast size in women).

Genetic Changes

Mutation: a heritable change in the DNA molecule.
Mutation can result in a gene coding for a protein with a different amino acid.
Mutations can be harmful or harmless (e.g., boosting the immune system against a virus).
Mutations can occur in embryos or during cell division.
Duplication or deletion of a chromosome can occur during reproduction.

Epigenetics

Changes in gene expression without altering the DNA sequence.
Example: genes active in developing fetuses become less active after birth.
Activation of genes involves loosening the grip of histones on DNA.
Adding an acetyl group (COCH3) activates a gene, while removing it tightens the grip again.

Heritability

When variation depends on genetic differences.
Determining heritability: comparing monozygotic twins and dizygotic twins, or adopted children and their biological parents.

Environmental Modification

High heritable traits can be modified by environmental interventions (e.g., phenylketonuria (PKU)).

How Genes Influence Behavior

Genes can influence behavior by altering the environment (e.g., attractive genes influence strangers' reactions, which in turn affect personality).

The Evolution of Behavior

Evolution: change over generations.
Species evolve through genetic influences, mutations, and increased reproduction.
Artificial selection: breeders choosing individuals with desired traits to produce the next generation.

Misunderstandings about Evolution

Lamarck's theory: not supported, as using or not using a body part does not affect its size or shape in the next generation.
Evolution is not slowing down or stopping due to modern medicine, as it is driven by reproduction, not survival.
Evolution is not always an improvement, but rather an adaptation to increase fitness and pass on genes.

Evolutionary Psychology

Studies how behavior evolves.
Some behaviors may seem unnecessary but have evolutionary explanations (e.g., goose bumps, infant grasp).
Altruistic behavior: can be selfish or selfless, with examples like family, kin selection, reciprocal altruism, and group selection.

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Description

This quiz covers the basics of genetics, including Mendelian genetics, sex-linked and sex-limited genes, and the structure of chromosomes, DNA, and RNA.