Chapter 18A ENS RED PDF

Chapter 18 Descent with Modification EVOLUTION 1 2  EVOLUTION Metamorphosis Evolution Ontogeny EVOLUTION Theory of Organic Evolution: Organisms (e.g., Plants and animals) on earth have been changing, and the ones around us tod...

Chapter 18 Descent with Modification EVOLUTION 1 2  EVOLUTION Metamorphosis Evolution Ontogeny EVOLUTION Theory of Organic Evolution: Organisms (e.g., Plants and animals) on earth have been changing, and the ones around us today are descendants of those that were here earlier. “Human beings, as we know them today, developed from an earlier species of animal” 5 Setting the stage for Darwin’s theory of “descent with modification” note date of publication: 1859 Consider the study of life Before Darwin, Wallace, & Mendel... Aristotle (384-322 BC), Scala Naturae Ole Worm, Museum Wormianum (1655)  Carolus Linnaeus (1707-1778) 1st ed. “Systema Naturae” 1735 10th ed. “Systema Naturae” 1758 Swedish botanist and physician Introduced binomial classification system, still used today (e.g., Homo sapiens) “Father of Taxonomy” grouped organisms according to similarity in morphological characteristics No kindness for amphibians: “These foul and loathsome animals…” -- Carl Linaeus, Systema Naturae, 1758. Carolus Linnaeus (1707-1778) Muséum National d’Histoire Naturelle, Paris  Georges-Louis Leclerc, Comte de Buffon (1707 –1788) French Naturalist Histoire naturelle, générale et particulière First evolution discussion In the course of his examination of the animal world, Buffon noted that despite similar environments, different regions have distinct plants and animals, a concept later known as Buffon's Law.  Georges Cuvier (1769-1832) French anatomist found fossils in layers of rock (strata); older layers are deeper extinctions implied by disappearance of species in fossil record proponent of catastrophism (past geological change & corresponding extinctions occurred in sudden dramatic events)  James Hutton (1726–1797) Scottish geologist proposed gradualism past geological change as a result of the same slow, continuous processes that are observable today (for example, erosion)  Jean Baptiste Lamarck (1744 - 1829) French naturalist Discussion of extinctions proposed evolution to explain changes in the fossil record mechanism: inheritance of acquired characteristics (wrong), explained through the ”use and disuse principle” Thomas Malthus (1766-1834) British political economist I think I may fairly make two postulata. First, That food is necessary to the existence of man. Secondly, That the passion between the sexes is necessary and will remain nearly in its present state. (EPP, Chapter 1) Essay on the Principle of Population (1798) limited resources + unchecked population growth = decline in living conditions Thomas Malthus (1766-1834) British political economist How many Americans is too many?  Charles Lyell (1797-1875) British geologist Principles of Geology 1830 uniformitarianism – (further development of Hutton’s gradualism); past geological events operated at the same rate as current processes - reconsider age of earth  Charles Robert Darwin (1809-1882) British naturalist http://www.imdb.com/title/tt0974014 Check out Darwin’s original drawings, correspondence, journal entries, etc. http://www.amnh.org/exhibitions/darwin/ Studied medicine Edinburgh University Seminary school at Cambridge University "You care for nothing but 'What a fellow that Darwin is shooting, dogs, and rat- for asking questions!’ catching, and you will be a — John Henslow, Botanist (Darwin's mentor) disgrace to yourself and all your family.“ — Robert Darwin (father of Charles) Reverend John Henslow 20  1831 voyage of the H.M.S. Beagle "The misery I endured from sea-sickness is far beyond what I ever guessed at.” Five years at sea. Captain Robert Fitzroy Islands, mainlands Geological events 1500+ species fossils US Independence, 1776 Alfred Russel Wallace (1823-1913) British naturalist independently develops similar theory - evolution (of species over time) - natural selection (as the mechanism) sends essay to Darwin for review in 1858 Lyell presents Wallace essay together with excerpts of Darwin’s work theory encounters strong public resistance “Truth is born into this world only with pangs and tribulations, and every fresh truth is received unwillingly.”  Charles Darwin's observations and conclusions: 1859--On the Origin of Species by Means of Natural Selection, or the Preservation of favored races in the Struggle for Life. Observations: 1. All organisms exhibit variability. 2. All organisms produce many more offspring than survive to sexual maturity. Conclusions: 3. Environment selects (natural selection). 4. Characteristics favored by selection are passed on to the next generation. We know today: Fact: Variability is due to random gene changes. Conclusion: Genes which code for more useful structures that permit more effective function are passed on more frequently. 23 To consider in the study of Evolution: Adaptations: inherited characteristics of organisms that enhance their survival. Natural selection: Individuals that have certain inherited traits survive and reproduce at higher rates. Natural selection acts on individuals. Individuals do not evolve. Populations evolve.  Figure 22.2 1809 Lamarck publishes his hypothesis of evolution. 1798 Malthus publishes “Essay on the Principle of Population.” 1812 Cuvier publishes his extensive 1858 1795 studies of vertebrate fossils. While studying species in Hutton proposes the Malay Archipelago, his principle of 1830 Wallace (shown in 1848) gradualism. Lyell publishes sends Darwin his hypothesis Principles of Geology. of natural selection. 1790 1870 1809 1831-36 1859 Charles Darwin Darwin travels around On the Origin of is born. the world on HMS Species is published. Beagle. 1844 Darwin writes his essay on descent with modification. The Galápagos Islands Life after Darwin & Wallace Earth is very old, millions and not thousands of years Species change over time; some go extinct, new ones arise Unity of life, all organisms have a common ancestor h$p://statedclearly.com/videos/what-is-evolu7on What is Evolution?  Sir Francis Galton (16 February 1822 – 17 January 1911) Greeks Plato suggested selective mating to produce a Guardian class Nazi Germany: Arian supremacy and mass murder of other ethnic groups US: Academic discipline in many schools for many years. over 64,000 individuals forcibly sterilized under eugenic legislation  Evidence for the Theory of Evolution Artificial selection Direct observation of evolutionary change Phylogenies Homology and convergent evolution Embryology and ontogeny Vestigial Structures Fossil record Biogeography  Evidence for the Theory of Evolution Artificial selection 2000 years Second Opium War, in 1860 Gautama Buddha (c. 563 BCE/480 BCE – c. 483 BCE/400 BCE) 30  Evidence for the Theory of Evolution Direct observation of evolutionary change – E.g., Darwin’s Finches, Peppered Moths  Evidence for the Theory of Evolution Phylogeny Assumptions of phylogenetic systematics. 1. Evolution occurs. 2. There is a single phylogeny for all life and it is the result of genealogical descent. 3. Characters are passed from generation to generation, modified or unmodified, during genealogical descent.  Evidence for the Theory of Evolution Homology & convergent evolution Patterns of Evolution: 33 33 1. Specialization in stable environments. 2. Flexibility in new and/or changing environments.  Evidence for the Theory of Evolution Homology & convergent evolution Characters can be divided into two broad categories: 1. Those that infer genealogical relationships (homologies). 2. Those that do not infer genealogical relationships (convergences and parallelisms). 34  Homology, Analogy and Homoplasy = function = func7on ≠ ancestry ≠ function ≠ ancestry = appearance ≠ ancestry ≠ appearance = appearance Features are Features may analogous if they Analogy Homoplasy also be related share a common (function) (appearance) by similarity of function. Same appearance. Homology (ancestry) = function ≠ function = ancestry = ancestry ≠ appearance = appearance ≠ function Features are homologous = ancestry if they share a common ≠ appearance ancestry.  Evidence for the Theory of Evolution Embryology and ontogeny Ontogeny (embryological history) 1. Baer's Law. States that general features common to all members of a group of animals develop earlier in ontogeny than do the special features that distinguish the various subdivisions of the group. 2. Haekel's Biogenetic Law. States that ontogeny should provide some indications of the phylogeny (evolutionary history) of any group. 3. Principle of recapitulation-- Ontogeny recapitulates phylogeny. 37  Evidence for the Theory of Evolution Ves8gial structures  Atavism Reincarnation of Hindu God Hanuman 39  Evidence for the Theory of Evolution Vestigial structures  Vertebrates and protochordates have paired series of clefts or Pharyngeal pouches and slits. pouches, developed from the anterior gut—the pharynx. Embryo. Lungs In mammals, only one or two of these pouches actually rupture to the outside, but these close again before birth. Persistent pharyngeal slits are known as a cervical fistula. 41 Cervical Fistulae Figure 5 (A,B) Excision of the scar tissue surrounding the fistula.  Evidence for the Theory of Evolution Fossil record  Evidence for the Theory of Evolution Biogeography  Evidence for the Theory of Evolution Biogeography Lungfishes, of Gondwanan distribution