16 Questions
What did Gregor Mendel's work reveal about the units of heredity?
They maintain their structural identity from one generation to another
What is the main difference between sex-linked genes and autosomal genes?
Sex-linked genes are found on sex chromosomes, autosomal genes are not
What type of genetic change results in a different amino acid in a protein?
Mutation
What is the term for the study of heritable changes in gene expression that do not involve a change in DNA sequence?
Epigenetics
How is heritability typically determined?
By comparing monozygotic twins and dizygotic twins
What is an example of an environmental modification that can affect a highly heritable trait?
Phenylketonuria (PKU)
How do genes influence behavior, according to the text?
By influencing physical attractiveness, which in turn affects social interactions
What is the term for the change in species over generations?
Evolution
What is the main reason for genetic influences in evolution?
Individuals with desired traits producing more offspring
What is the main flaw in Lamarck's theory of evolution?
It suggests that acquired traits can be passed on
Why is the idea that modern medicine slows down or stops evolution incorrect?
Because evolution is based on survival, not reproduction
What is the correct understanding of the term 'evolution'?
It means increasing an individual's fitness
What is an example of an altruistic behavior in animals?
A crow calling out to attract other crows for protection
What is the term for selecting genes that benefit an individual's relatives?
Kin selection
What is the term for expecting help in return for altruistic behavior?
Reciprocal altruism
What is the term for the process of evolution at the group level?
Group selection
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.
This quiz covers the basics of genetics, including Mendelian genetics, sex-linked and sex-limited genes, and the structure of chromosomes, DNA, and RNA.
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