Evolutionary Biology - Midterm

• Evolution


  A change in the genetic composition of a population over time
• Evolvere


  Latin word meaning "to unfold or unroll"
• Evolution


  A change in the frequency of certain alleles
• Evolution


  The gradual appearance of all biological diversity
• Evolution


  Descent with modification
• Factors affecting evolution


  • Mutation
  • Migration
  • Genetic Drift
  • Natural Selection
• Mutation


  A change in genes that can make offspring have different traits than their parents
• Migration


  Individuals from one population joining another population
• Genetic Drift


  Chance changes in the frequency of traits from one generation to the next
• Natural Selection


  The process where organisms with advantageous traits are more likely to survive and reproduce
• Evolutionary Biology


  A discipline of biology concerned with the processes and patterns of biological evolution, especially in relation to the diversity of organisms and how they change over time
• Great Chain of Being


  The belief that there is a permanent and unchanging gradation from inanimate objects to higher forms of life, with humans as the link between animals and angels
• Carolus Linnaeus


  Established the framework of modern taxonomy, classifying related species into genera, orders, etc.
• Uniformitarianism


  The belief that Earth's landscapes formed through slow, steady and constant processes
• Lamarck's theory


  Alterations acquired during an individual's lifetime are inherited
• Charles Darwin


  Provided evidence that existing species have evolved from pre-existing ones, and proposed the theory of evolution by natural selection
• Descent with modification


  All species came from one or few original forms
• Natural Selection


  The chief cause of evolutionary change
• Components of Natural Selection

  • Overproduction
  • Variations
  • Competition
  • Differential Reproductive Success
• Evidence supporting Darwin's theory

  • Fossil records
  • Fossil dating
  • Radiometric dating
  • Comparative anatomy
  • Distribution of plants and animals
  • Related species development patterns
  • Molecular comparisons
• Principles of Darwin's theory

  • Perpetual Change
  • Common Descent
  • Multiple Species
  • Gradualism
  • Natural Selection
• Alfred Russel Wallace


  Co-discoverer of the theory of natural selection, emphasized that natural selection drives reproductive isolation
• Homology


  The central concept in comparative biology
• Evidence of evolution


  • Fossil records
  • Embryology
  • Comparative anatomy
  • Molecular biology
• Comparative anatomy


  • Study of the similarities and differences in the anatomy of different species
  • It supports evolution by providing evidence that supports or dismisses the relatedness of two organisms
• Types of relationship among structures

  • Homologous structures
  • Analogous structures
• Analogous structures


  Anatomical features that are superficially similar to one another, but have quite different evolutionary origins and developmental patterns
• Analogy/Homoplasy


  When similar characteristics occur because of environmental constraints and not due to a close evolutionary relationship
• Homologous structures


  Similar physical features in organisms that share a common ancestor, but the features may or may not completely different functions
• The Tree of Life

  Darwin's proposal that all species, extant and extinct, form a great "Tree of Life," or phylogenetic tree

  
• LUCA means Last Universal Common Ancestor
• Phylogeny


  The evolution of genetically related group of organisms
• Phylogeny was coined by the developmental biologist Ernst Haeckel in 1866 and then championed by Darwin in his famous work, On the Origin of Species (beginning with the 5th edition in 1869)
• Phylogeny


  • Likened to a family tree
  • Method clusters groups of organisms together based upon shared, unique characters called synapomorphies

  
• Higher taxon


  A named group of organisms above the species level
• Types of homologies


  • Molecular homology
  • Historical homology
  • Phylogenetic/cladistic character homology
  • Biological homology
  • Syngeny/generative homology
• Molecular homology


  Similarities can be found at the molecular level, like the genetic code being universal and different organisms sharing genes that have been inherited from a common ancestor
• Anagenesis


  The evolutionary change of features within a single lineage (species)
• Cladogenesis


  A branching lineage into two or more descendant lineages
• Homologies and the tree of life

  Darwin's evolutionary tree of life can explain homologies - the genetic code is shared by all species because it goes back deep into the ancestral past, and more recent homologies are shared by only smaller branches of the tree