Chapter 5: Modern Evolutionary Theory (Mendelian Genetics (Mendel's…
Chapter 5: Modern Evolutionary Theory
Modern Synthesis of Evolution
All organisms are the product of interactions between biology, environment, society, culture, & history
Various perspectives to study cultural transmission, e.g. sociobiology: "cultural" gene = meme
Natural Selection behavioural traits
Human behaviour=phenotype, behaviour = heritable, e.g. childrens behaviour
Origin of species(macroevolution) depends on natural selection on individual phenotypes(microevolution)
Evolution is gradual, though small genetic changes acted on by natural selection
Sources of Biological Variation
Epigenetics: interaction of genes during development that influences the phenotype
Hybridization: creation of viable offspring between two species
Gene Flow:Movement of genes between populations(through mating).
: Variation in gene frequency across a region
Genetic Drift: Fluctuations in allele frequency by chance, usually in small populations.
Creates genetic divergence between populations
Mutation: Change in DNA sequence, errors in translation/transcription.
Genetic Recombination:Chromosomes segregate independently and randomly during meiosis. Crossing over.
Discrete traits: phenotypical expression controlled by a single gene
Meiosis: halves chromosome number so offspring have correct number of chromosomes
Mitosis: making copies of the cells
DNA: genetic code of organisms. 4 bases A T G C
Chromosomes: contain most of cells DNA
Genotype: genetic composition of a trait
Phenotype: Observable physical trait
Mendel's Law of Segregation
4) One allele from each parent
3) Dominant vs. Recessive alleles
2) Two alleles per gene, homozygous = same two alleles, heterozygous = two different alleles
1) Genes= unit of heredity, Alleles = alternative versions of genes
Peas as test subjects
Identified mechanism of heritability(how traits are passed to offspring)