Darwin’s Theory Of Evolution

1/8/20181. The History of LifeDARWIN’S THEORYOF EVOLUTIONTurner College & Career High School 2015Define These Evolution Theory change over time; the process by which modernorganisms have descended from ancient organisms.They are Connected Evolution is atheory; a testableexplanation ofnaturally-occurringphenomena.EvolutionThe fossils thatDarwin found causedhim to ask questionsthat led to his theoryof evolution.a well-supported, testable explanation of phenomenathat have occurred in the natural world.Fossil Theorythe preserved remains of ancient organisms.FossilThe fossil record provides for some theevidence to support the theory of evolution.Flashback The total variety of all the organisms in thebiosphere biodiversity.What scientific explanation can account for thediversity of life? A collection of scientific facts, observations,and hypotheses known as evolutionarytheory.Proof of Evolution Fossil Record –Fossils are theremains of ancientorganisms found inlayers of rock in theEarth.1

1/8/2018Proof of Evolution The layers of rocktell the history ofthe Earth, whilethe fossils foundwithin the rock tella history of life.The fossils arethought to be thesame age as therock they arefound in.Movement of Earth’s CrustEarthquakes and volcanoes cause uplifting of thelayers of the Earth, taking the fossils along.Fish die inthe oceanand arecovered insediment.Over timeand underincreasingpressure,the remainsbecomesfossilizedSeaLevelSedimentaryrocks form inhorizontal layers.When part of Earth’scrust is compressed, abend in a rock forms,tilting the rock layers.As the surface erodesdue to water, wind,waves, or glaciers,the older rock surfaceis exposed.Movement of Earth’s CrustMovement of Earth’s CrustPlate TectonicsPlate TectonicsFossils ofmarinefish foundon themountainsides ofsouthwestWyoming,which atone timewascoveredby aninland sea2

1/8/2018Theory of PangaeaPangaea was a believed to be thesupercontinent that existed duringthe late Paleozoic and earlyMesozoic eras, forming about 300million years ago and beginning torift around 200 million years ago,before the component continentswere separated into their currentconfigurations.Charles Darwin The person who was mostinfluential to ourunderstanding of evolution.In 1831, at age 22, he joined thecrew of the HMS Beagle as anaturalist for a 5 year voyagearound the world.Darwin’s Observations Why do Argentina and Australia have differentanimals even though they have similargrassland ecosystems?Why are there no rabbits in Australia and nokangaroos in England?Why have so many species disappeared?How are these extinct speciesrelated to living species?2. Charles DarwinDarwin and the HMS Beagle During his travels, Darwin wrote thousands ofpages in his journals, drew pictures of the thingshe saw, and collected a vast amount of evidencethat led him to propose a revolutionaryhypothesis about the way life changes.Galápagos Islands While on his voyage around the world aboardthe HMS Beagle, Darwin spent about one monthobserving life on the Galápagos Islands. There, he encounteredsome unique animals,such as finches andtortoises.3

1/8/2018Galápagos IslandsGalápagos Islands Galápagos TortoisesThe Galápagos Islands are close together but have verydifferent climates.Some were hot and dry, with little vegetation.Others had more rainfall and were rich in vegetation.Each island had its own unique assortment of plant andanimal species.Galápagos Tortoisesand on Pinta Island, tortoise neckswere somewhere in between.On the desert-like Hood Island,tortoises had long necks while on the lush rainforest of IsabelaIsland, tortoises had short necks Galápagos FinchesGalápagos Finches4

1/8/2018Darwin’s Findings Concept MapAfter his voyage, Darwin spent a great deal oftime thinking about his findings.He began to wonder if animals living ondifferent islands had once been members ofthe same species that had developed differentcharacteristics after becoming isolated fromone another in different habitats.Evidence ofEvolutionIncludesThe Fossil RecordGeographicDistribution ofLiving SpeciesHomologous BodyStructuresSimilaritiesin EarlyDevelopmentwhich is composed ofwhich indicateswhich implieswhich impliesPhysical Remainsof OrganismsCommon AncestralSpeciesSimilar GenesSimilar GenesDarwin’s Findings3. Darwin Presents His Case After Darwin returned to England in 1836 hefilled notebooks with his ideas about speciesdiversity and the process that he would later callevolution.He did not rush to publish his ideas becausethey disagreed with the fundamental scientificbeliefs of his day.He asked his wife to publish his ideas when hedied.Wallace’s EssayOrigin of SpeciesIn 1858, another naturalist, Alfred Russell Wallacewrote an essay describing his work in Malaysiathat summarized the same ideas Darwin had beenthinking about for 25 years. Suddenly Darwin had incentive to publish theresults of his work.In 1859 On the Origin of Species presentedevidence and proposed a mechanism forevolution that he callednatural selection.5

1/8/2018Evolution is a THEORY A theory is a well-supported, testable explanation ofphenomena that have occurred in the natural world, likethe theory of gravitational attraction, cell theory, oratomic theory.Keys to Darwin’s Theory Struggle for existence means that members ofeach species must compete for food, space, andother resources.Keys to Darwin’s Theory Survival of the fittest means organisms whichare better adapted to the environment willsurvive and reproduce, passing on their genes.Keys to Darwin’s Theory Genetic variation is found naturally in allpopulations.Keys to Darwin’s Theory Some organisms in a populationare less likely to survive.Vocabulary Fitness is the ability of an individual to surviveand reproduce in its specific environment. Thisleads to Hmmm 6

1/8/2018VocabularyVocabularyAdaptation is any inherited characteristic thatincreases an organism’s chance of survival.A transitional fossil is anyfossilized remains of a life formthat exhibits traits common to bothan ancestral (original) group andits derived descendant (new)group. This is especially importantwhere the descendant group issharply distinguished by anatomyand mode of living from theancestral group.What is Darwin’s Theory? Over time, natural selection results in changes inthe inherited characteristics of a population.These changes increase a species’ fitness in theirenvironment.How does it work? Descent with modification suggests that eachspecies has descended with changes, fromother species over time. This idea suggests that all living species are relatedto each other; and that all species, living andextinct, share a common ancestor.7

Evolution is a THEORY A theory is a well-supported, testable explanation of phenomena that have occurred in the natural world, like the theory of gravitational attraction, cell theory, or atomic theory. Keys to Darwin’s Theory Genetic variation is found naturally in all populations. Keys to Darwin’s Theory