BIOL 112 1st Edition Lec-ture 4 Outline of Last Lecture I. The Scientific MethodII. EvolutionA. Observations Significant to EvolutionIII. FossilsIV.Macroevolution of HorsesV. How Old are Fossils?A. Relative DatingB. Absolute DatingVI.Dating MathA. Calculating AgeVII. Carbon DatingVIII. Geological DatingIX.Dating ObservationsOutline of Current LectureX. What Do We See in Fossils?XI.Anatomical EvidenceXII. Interpretation of HomologyXIII. Vestigial OrgansXIV. EmbryologyA. What does it mean?XV. Molecular HomologiesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.XVI. InterpretationsA. Theories of EvolutionXVII. St. Augustine of HippoA. Problems with Augustine ModelXVIII. The EnlightenmentXIX. Jean Baptiste LamarckA. Examples of Lamarck’s ModelB. Tests of Lamarck’s ModelXX. Charles Darwin (1809-1882)Current LectureI. What Do We See in Fossils?•Few living organisms also seen in fossil record. If they are, most such fossils are quite recent, not ancient•The older the rocks/fossils, the less they resemble modern life forms•Many extinct species in the fossil record; most fossils represent species not seen today•Fossils provide a record of evolution: appearances, disappearances and changes of or-ganisms over long periods of time on the planet.II. Anatomical Evidence•Homology -- fundamental identity of structure/organization of structures in living crea-tures similar, in spite of possible differences in functionExample: vertebrate forelimb. Details highly modified, but same fundamental pattern of arrangement of bones, muscles, nerves, blood vessels, etc., among all vertebrate animals•Distinguish from analogy -- similar function of structures on two different creatures, but different organizationsExample: wing of bird and wing of insect. Both flight organs, but different struc-tures/organizationConcept of homology developed in 18th Century, before concept of evolutionIII. Interpretation of HomologyTheory is that all vertebrates descended from an original ancestor with fundamental forelimb bone arrangement•Differences in details (proportions, sizes, functions) developed over time, but all verte-brate forelimbs retain same common fundamental underlying pattern of organization•Concept supported by detailed fossil evidence from early vertebrate evolution•Concept further reinforced by molecular evidence: sets of homologous genes used to develop homologous structures in different organismsIV.Vestigial OrgansFeatures in an organism that exist, but to what purpose?Related to homology:•Snakes have what looks like rudimentary pelvis and legs near anus•Whales retain rudimentary pelvis and legs•Fold of skin in inner corner of human eye -- vestigial nictating membrane (haws of cats or dog)•Ear wiggling muscles in some humans -- homologous to muscles in animal ears (cat or horse)Appear to be remains of organs that were more developed in past history of species (or its ancestors), but no longer developed or used.V. EmbryologyPrimitive (ancestral) structures seen in embryos that are not present in later develop-mental stagesPhylotype Stage:•Fish embryos: pharyngeal pouches become components of the gills•Mammal; bird; reptile embryos: pouches develop into jaw bones, ear bones, etc.•Human embryos with tails; lost at later stagesEmbryos retain primitive developmental features, regardless of later fates/uses of fea-tures<<This is not the same phenomenon as vestigial organs; those apply to adult form only>>A. What does it mean?Developmental homologies: common animal embryonic developmentalsequences for a diverse collection of species and adult organsRetention of basic developmental events (developmental pathways) re-gardless of later modifications (von Baer's Law - 18th century)Suggests that embryos with common developmental patterns have a common ancestry -- similarities in timeVI.Molecular Homologies•Organisms have homologies among their gene sequences and organization as well as in their anatomy and development•All organisms use essentially the same genetic code•Similar (closely related) organisms use extremely similar (homologous) genes, expressed in similar patters of time and space, to produce homologous structures•More distantly related organisms have fewer molecular sequence similarities than closely related groups•Diverse organisms had a common ancestor with particular set of genes/sequencesVII. InterpretationsAll studies (fossils, anatomical homologies, embryology, molecular sequences) indicate that evolution has occurred•Evolution is a fact: living things have changed and do change over time•Critical question for interpretation: how does evolution occur? What is mechanism?Theories of Evolution•Attempts to explain observed facts. Evaluate these models by scientific standard techniquesA. Theories of Evolution•Must meet same evolution criteria as any other theory: explain and predict.•Many have been proposed and considered: some discarded, some still being evaluated.•Homeobox - Homology of arrangement of patterning genesVIII. St. Augustine of Hippo•Philosopher and theologian, Bishop of Hippo (Carthage, N. Africa) 4th Century, CE•Church father: write Confessions and City of God. Application of pagan philosophy/logic to Christian theology. Rationalization of Christian theology•Proposed that God created universe at some remote time in a form unlike today, but with the potential to develop eventually to present-day conditions•Required a very long time (unspecified)•"Programmed universe" -- evolution of humans and other present species inevitableA. Problems with Augustine Model•God is central component of theory -- supernatural entity•Science unable to analyze supernatural (metaphysical) phenomena•Theory thus becomes unfalsifiable•Basic trouble with all such creationist modelsIX.The Enlightenment•Formalization of scientific method in 16th and 17th Centuries•Expansion of scientific knowledge through 18th and 19th Centuries. Fossil record ana-lyzed and understood; embryology and anatomy, exciting new discoveries•Mass of data waiting for interpretationX. Jean Baptiste Lamarck•Naturalist (geologist/biologist/anthropologist) in late 18th Century•First rigorously stated, testable theory of evolution•Recognized that evolution had occurred and that new species of plants and animals arose from older, ancestral