THE ESSENTIAL 30 FACTS FOR NEET

Chemical Evolution

1. Miller-Urey (1953): CH4 + NH3 + H2 + H2O → amino acids via electric discharge
2. No O2 in Miller-Urey (reducing atmosphere)
3. Oparin + Haldane = proposers of chemical evolution hypothesis

Homologous vs Analogous 4. Homologous = same origin, different function → divergent evolution 5. Analogous = different origin, same function → convergent evolution 6. Forelimbs of mammals = homologous (bat, whale, horse, human) 7. Wings of bat + butterfly = analogous (most tested pair) 8. Wings of bat + bird = HOMOLOGOUS (both vertebrate forelimbs) 9. Thorns (Bougainvillea) + tendrils (Cucurbita) = homologous (both stem) 10. Eyes of octopus + mammals = analogous

Hardy-Weinberg 11. p + q = 1 (allele frequencies) 12. $p^{2}$ + 2pq + $q^{2}$ = 1 (genotype frequencies) 13. $p^{2}$ = AA, 2pq = Aa (carrier), $q^{2}$ = aa (recessive phenotype) 14. ALGORITHM: $q^{2}$ → q → p → 2pq → multiply by N 15. Five conditions: no mutation, no migration, no selection, large population, random mating 16. ANY violation → evolution occurring

Natural Selection Types 17. Stabilizing: favours intermediate → reduces variation 18. Directional: favours one extreme → shifts mean 19. Disruptive: favours both extremes → may cause speciation

Speciation 20. Allopatric: geographic isolation → gene flow stops → divergence → new species 21. Sympatric: same area → polyploidy (plants) → new species instantly 22. Adaptive radiation: one ancestor → many species → different niches 23. Darwin's finches + Australian marsupials = adaptive radiation examples

Human Evolution (D-R-A-H-E-S) 24. Dryopithecus: 15 mya, 300-400 cc, ape-like 25. Ramapithecus: 14 mya, more erect 26. Australopithecus: 5 mya, 400-500 cc, FIRST BIPED 27. Homo habilis: 2 mya, 600-700 cc, FIRST TOOL-MAKER (Oldowan) 28. Homo erectus: 1.5 mya, 800-1100 cc, FIRST FIRE USER, first out of Africa (Acheulean) 29. Homo sapiens: 0.2 mya, 1300-1400 cc, art, language, agriculture 30. Neanderthals: ~1400 cc, cold-adapted, buried dead

NEET DANGER ZONES (Most Likely to Be Tested as Traps)

• Bat wing vs butterfly = ANALOGOUS (not homologous)
• Bat wing vs bird wing = HOMOLOGOUS (not analogous)
• Australopithecus = first BIPED (not first tool-maker)
• Homo habilis = first TOOL-MAKER (not first biped)
• Homo erectus = FIRE (not Homo habilis)
• H-W: "constant mutation rate" STILL violates equilibrium
• H-W: small population violates "large population" condition (genetic drift)