Key Points Evolution: Darwin's Theory & Evidences (Part 2)

	Evolution of Life: Charles Darwin: ship – HMS Beagle Location: Galapagos;  Animal: Finches
	Theory of Natural Selection: Mechanism of Evolution 1.       Population if unchecked increases exponentially 2.       Resources are limited leading to struggle 3.       Population has built in variations in characteristics 4.       Characters which help an individual to survive better in natural conditions are favoured 5.       This leads to survival of the fittest. ‘Fit’ / ‘Fitness’ by Drawin refers only to Reproductive fitness
	Similar conclusions given by Wallace, work at Malay Archipelago.
	Evidences of Evolution: 1.       Fossils/Paleontological Evidence 2.       Comparative Anatomy & Morphology 3.       Embryology 4.       Molecular Evidences
	Fossil: hard parts of life forms found in rocks. Age estimated by C dating
	Comparative Anatomy: Similar structures developed along different lines due to different needs of the organism (adaptations) – Divergent Evolution. Structures k/a Homologous Homology indicates common ancestry e.g. forelimbs of mammals (bats, whales, humans – all have humerus, radius, ulna, carpals, metacarpals & phalanges) Vertebrate Heart/Brains Thorn & Tendril of Bougainvillea & Cucurbita
	Different Structures evolving for similar functions, hence appear similar – convergent evolution Structures k/a analogous e.g. eye of octopus & mammals flippers of Penguins & Dolphins sweet potato root & Potato Stem
	Embryological Evidences: Biogenetic Law: Ontogeny recapitulates Phylogeny Given by Haeckel Ontogeny – development of embryo Phylogeny: development of race / evolution Thus during embryo stages of all vertebrates, embryos of fish are seen In plants: Protonema of ferns & Moss similar to Algae Primitive Gymnosperms have flagellated sperms like Pteridophytes Leaves in seedlings of Acacia are similar, while in adults – compound
	Molecular  Evidences: Biochemical Similarity Similarity in amino acids, nucleic acids, Common Genetic Code Only 1.8% difference in DNA of Humans & Chimpanzee Amino acids sequence of Cytochrome C – identical in them.