Introduction
Mendel's laws, sex determination (XX/XY), and evolution through natural selection and speciation.
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Inheritance and Evolution
Genes exist in pairs (alleles). Dominant expressed in heterozygous. Monohybrid Tt x Tt: 3:1 phenotypic ratio. Dihybrid: 9:3:3:1. Sex: XX=female, XY=male; father determines sex. Evolution: natural selection (survival of fittest), variation is raw material. Speciation through geographic isolation. Homologous organs: same origin, different function (common ancestry).
Key Points
- •Monohybrid F2: 3:1 ratio
- •XX=female; XY=male; father determines sex
- •Natural selection: advantageous traits survive
- •Speciation: geographic isolation->new species
- •Homologous organs: common ancestry
Quick Summary
- ✓Mendel: 3:1 monohybrid, 9:3:3:1 dihybrid
- ✓XX=female, XY=male
- ✓Evolution by natural selection
- ✓Homologous: same origin; Analogous: different origin
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