Origin of Life:
Hypothesized early conditions on Earth.
Miller-Urey experiment: Simulated early Earth conditions and observed formation of amino acids.
RNA world: Idea that RNA was the first genetic material.
Biological Evolution:
Changes in populations over generations due to genetic variations.
Variations arise due to mutations, gene migration (gene flow), and genetic drift.
Theories of Evolution:
Lamarck’s Theory: Principle of use and disuse; inheritance of acquired characters.
Darwin’s Theory: Natural selection; survival of the fittest.
Adaptive Radiation: Organisms from a common ancestral species evolve and radiate into different forms in different habitats. Example: Darwin’s finches.
Evolution by Stages: Complex structures develop in stages over time. E.g., eyes, wings.
Human Evolution:
Humans (Homo sapiens) are believed to have evolved from primates.
Various stages: Dryopithecus, Ramapithecus, Australopithecines, Homo habilis, Homo erectus, Neanderthal man, and finally Homo sapiens.
Hardy-Weinberg Principle: Describes a population that is not evolving. If a population does not meet the criteria of the principle, it’s evolving.
Sources of Genetic Variation:
Gene migration or gene flow
Genetic drift (random change in allele frequencies, especially in small populations)
Mutation
Recombination
Speciation: Process by which new species develop. Can occur due to:
Reproductive isolation
Geographical isolation
Molecular Phylogeny: DNA sequencing used to determine evolutionary relationships.
Evolution and Classification:
Evolutionary relationships can be traced through classification systems, especially in phylogenetics.
Evolution Impact: On other areas of biology, like comparative anatomy and molecular biology.