CH8BIO

• Panspermia argues that life originated in another planet in the universe and reached earth accidentally
• Organic substances obtained from meteors that fell on earth support the Panspermia theory
• Theory of chemical evolution suggests that life originated from changes in chemical substances in seawater under specific conditions on primitive earth
• A.I. Oparin and J.B.S. Haldane are proponents of the theory of chemical evolution
• Urey and Miller experiment recreated the atmosphere of primitive earth containing methane, ammonia, hydrogen, and water vapor
• High voltage electricity was passed through the gaseous mixture in the experiment instead of natural energy sources like thunder and lightning
• Organic molecules such as amino acids were found in the sediment substances in the Urey-Miller experiment
• Organic compounds were formed in the oceans of primitive earth due to chemical evolution over millions of years
• Jean Baptist Lamarck proposed Lamarckism, where acquired characters developed during an organism's lifetime are not inheritable
• Charles Darwin proposed Darwinism, where natural selection leads to the diversity of species
• Darwin's theory of evolution was based on observations made during his voyage to the Galapagos Islands on the HMS Beagle
• Darwin's theory of natural selection explains that variations in organisms lead to the survival of those with favorable variations
• Neo-Darwinism is a modified version of Darwinism that incorporates new information from genetics, cytology, geology, and paleontology
• Mutation theory explains that new species are formed by inheriting sudden changes in genes, known as mutations
• Evidences of evolution include paleontology, comparative morphology, physiology, and modern molecular biology
• Fossils are remnants of primitive organisms and provide evidence of the history of life on earth
• Oldest known fossils date back to about 3.5 billion years ago and are of prokaryotes
• Homologous organs are organs with similar structures but perform different functions, showing adaptations to different habitats
• Primitive cell - 3800

  Prokaryotes - 3500

  Eukaryotes - 1500

  Colony of eukaryotes - 1000
• Founder of Lamarckism: Lamarck
• Founder of Darwinism and evolution theory: Charles Darwin
• Galapagos finches:

  • Woodpecker finch
  • Insectivores Finch
  • Cactus Eating Finch
  • Small ground Finch
  • Large Ground Finch
  • Tree Finch
  • Medium Sized Tree Finch
  • Ancestor Finch
• Economist: Robert Malthus
• Theory of Natural Selection:

  • Organisms With Variations
  • Over Production
  • Struggle For Existence
  • Those with no favourable conditions
  • Destroyed
  • Those with favourable Conditions
  • Natural selections
  • Survive
  • Favourable variations are transferred to the next gen
  • Accumulation of variation inherited through gen
  • Origin of new species
• Mutation Theory: Hugo Devris
• Evidence provided by fossils:

  • Primitive fossils have simple structure
  • Recently formed fossils have complex structures
  • Certain fossils are connecting links between different species
• Biochemistry and physiology:

  • Bacteria
  • Enzymes control chemical reactions
  • Energy is stored in ATP molecule
  • Genes determine the heredity of cells
  • Carbohydrates, fats, and proteins are the basic structure
  • Human being
• Molecular biology:

  • Chimpanzee
  • No change
  • Gorilla
  • Rat
  • Difference of one amino acid
  • Difference of 31 amino acids
• Evolution:

  • Monkey
  • Gibbon
  • Orangutan
  • Gorilla
  • Chimpanzee
  • Man
  • Cercopithecoidea
  • Small brain
  • Long tailed
  • Hominoidae
  • Developed brain
  • Freely
  • Movable hands
  • Anthropoidea
• Atmosphere of primitive earth:

  • Gases like hydrogen, nitrogen, carbon dioxide, methane, ammonia, water vapor, hydrogen sulphide, etc.
  • No free oxygen
• Source of energy:

  • Thunder and lightning
  • Ultraviolet radiations
  • Volcanic eruptions
• Condensation of water vapor present in the atmosphere and the resulting incessant rain led to the formation of oceans
• Simple organic molecules:

  • Amino acids
  • Monosaccharide
  • Nitrogen bases
  • Fatty acids, etc
• Complex organic molecules:

  • Protein
  • Polysaccharide
  • Nucleotides
  • Lipids, etc
• Every species produces more offspring than can survive on earth
• Offspring compete for food, space, and mates
• Competition becomes intense when there are more organisms and fewer resources
• Organisms exhibit many variations, which can be favourable or unfavourable
• Organisms with favourable variations survive in the struggle for existence
• Variations that are inherited through generations help form species different from their ancestors