Genes 

Gene Inheritance

• Genes exist on long DNA strands in chromosomes, like beads on a string
• Chromosomes come in pairs

Locus: location of a gene on a pair of chromosomes

Allele: different genes that occupy the same locus on a chromosome pair

Mendelian Patterns of Heredity: controlled by single pairs

Dominant allele: produces effects in both homo and heterozygous conditions

Recessive allele: produces effects in the homozygous condition only

First generation (F1): cross-pollinated white flowers (ww) with purple flowers (WW)

• Since W is dominant all were purple
• All had Ww alleles

Mendelian vs. Polygenic Characteristics

Single gene characteristics: creates sharp distinctions between traits

Polygenic characteristics: varies in a continuous fashion

• forms normal distribution

Selective Breeding

Selective Breeding: mating of individuals that lie toward the same extreme on the measure in question

Mendelian trait: immediate effect

Polygenic: the gradual, cumulative effect

Maze Learning: Tryon’s Classic Research

• Frist long term study of selective breeding

Maladaptive outcome: In the process of domesticating dogs, humans have inadvertently bred maladaptive features in dogs, such as floppy eats and smaller jaws, because these features are associated with tameness

Purebred health issues: many dogs breed practice inbreeding in order to maintain or accentuate certain features, but this makes certain dog breeds more susceptible to developing heredity illness

• Common health issues include joining problems, respiratory problems, eye problems, and autoimmune disorders

Epigenetics

Epigenetics: examines the “gene-regulating activity” that doesn’t involve changes to the DNA code and that can persist through one or more generations

• In addition to genes, we also inherit a variety of chemical markers that regulate genes
• While every cell contains the same DNA structure, every gene is active every time in every situation

DNA methylation: a best-understood mechanism for epigenetics

Natural Selection

Functionalism: attempt to explain behavior in terms of what it accomplishes for the behaving individual

Distal Explanations: explanation at the evolutionary level: describes how the behavior has contributed to the survival and reproduction of the animal over evolutionary time

Proximate Explanations: mechanical, describe the immediate conditions, inside and outside the organism that bring the behavior

Species Typical Behavior: characteristic behaviors common the nearly all members of a species

Darwins’ finding: human emotional expressions are STBs

Ekman and Wallaces’ findings: people in every culture described some photographs of basic human emotions in similar ways

Homology: similarities are due to common ancestry

Mating Patterns

Robert Trivers Studies: parental investment correlated with the number of mates

• The competition also develops for the highly invested parent

Monogamy: one male mates with one female; equal investment and equal competition; emerges when difficult to raise offspring

Polygamy: relative to many mates

Polygyny: high female investment and high competition for female mates

Polyandry: high male investment and high competition for male mates

Promiscuity: multiple males and multiple females mate with each other

Hurting and Helping

Aggression: behavior intended to harm another member of the same species

• Functions to gain access to higher social rank, thus sexual partners

• Related to Robert-Tiverers mating patterns

Patterns of Helping: behavior that increases the survival chance or reproductive capacity of another individual

Cooperation: when an individual helps another while helping itself

Altruism: increasing the survival reproductive chances of another at the expense of one’s own

Kin selection theory: altruism came about because it helps close relatives

Fallacies to Avoid

Fallacy: a false notion, statement, or argument based on invalid reasoning

Naturistics Fallacy: the idea that “natural” equals “moral”

• Nature itself is not moral or immoral

• noting is more evolved than anything else

Deterministic Fallacy: assumption that genes control rather than influence behavior which we can do nothing about

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