CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Brief Introduction to the Theory of Evolution Anders Gorm Pedersen Molecular Evolution Group Center for Biological Sequence Analysis

CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Classification: Linnaeus Carl Linnaeus

CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Classification: Linnaeus Hierarchical systemHierarchical system –Kingdom(Rige) –Phylum(Række) –Class(Klasse) –Order(Orden) –Family(Familie) –Genus(Slægt) –Species(Art)

CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Classification depicted as a tree

CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Classification depicted as a tree SpeciesGenusFamilyOrderClass

CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Theory of evolution Charles Darwin

CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Phylogenetic basis of systematics Linnaeus:Linnaeus: Ordering principle is God. Darwin:Darwin: Ordering principle is shared descent from common ancestors. Today, systematics is explicitly based on phylogeny.Today, systematics is explicitly based on phylogeny.

CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Darwin’s four postulates  More young are produced each generation than can survive to reproduce.  Individuals in a population vary in their characteristics.  Some differences among individuals are based on genetic differences.  Individuals with favorable characteristics have higher rates of survival and reproduction.  Evolution by means of natural selection  Presence of ”design-like” features in organisms: quite often features are there “for a reason”

CENTER FOR BIOLOGICAL SEQUENCE ANALYSIS Theory of evolution as the basis of biological understanding ”Nothing in biology makes sense, except in the light of evolution. Without that light it becomes a pile of sundry facts - some of them interesting or curious but making no meaningful picture as a whole” T. Dobzhansky