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Brittany Brown --Evolution

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This is an example of a student presentation from a Biology I class I taught.

This is an example of a student presentation from a Biology I class I taught.

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  • 1. Earth’s Change Over TimeEarth’s Change Over Time (Evolution)(Evolution) Brittany BrownBrittany Brown Biology 1-5Biology 1-5thth periodperiod May 1,2007May 1,2007
  • 2. IntroductionIntroduction In life there have been different theories asIn life there have been different theories as to how life came about. Many scientists haveto how life came about. Many scientists have wonder how Earth continued to change over awonder how Earth continued to change over a period of time. In Mr. Parr class he has ask hisperiod of time. In Mr. Parr class he has ask his students to present a power point presentationstudents to present a power point presentation and the Earth Change Over Time or somethingand the Earth Change Over Time or something related to that topic. These are the followingrelated to that topic. These are the following students in his 5students in his 5thth period class:period class:
  • 3. Key ConceptsKey Concepts  Earth has been home to living things forEarth has been home to living things for about 3.8 billion years.about 3.8 billion years.  Species change over time.Species change over time.  Many types of evidence support evolution.Many types of evidence support evolution.
  • 4. Vocabulary Chapter 1Vocabulary Chapter 1  AdaptationAdaptation  AncestorAncestor  EvolutionEvolution  FossilFossil  GeneGene  Mass ExtinctionMass Extinction
  • 5. Vocabulary Chapter 1Vocabulary Chapter 1  Multicellular OrganismMulticellular Organism  Natural SelectionNatural Selection  SpeciationSpeciation  Unicellular OrganismUnicellular Organism  Vestigial OrganVestigial Organ
  • 6. Earth’s Change Over TimeEarth’s Change Over Time (Evolution)(Evolution) Earth has been home to living thingsEarth has been home to living things for about 3.8 billion years.for about 3.8 billion years.
  • 7. Earth has been home to livingEarth has been home to living things for about 3.8 billion years.things for about 3.8 billion years.  Fossils provide evidence about the history of lifeFossils provide evidence about the history of life on Earth. Most fossils are hard body parts oron Earth. Most fossils are hard body parts or bone. Others form when minerals replace thebone. Others form when minerals replace the remains of organisms. Fossils also include printsremains of organisms. Fossils also include prints left by organisms, such as footprints. Very rarely,left by organisms, such as footprints. Very rarely, a fossil is the preserved remains of an organism,a fossil is the preserved remains of an organism, such as a wooly mammoth in ice or an insectsuch as a wooly mammoth in ice or an insect preserved in sap.preserved in sap.
  • 8. Earth has been home to living thingsEarth has been home to living things for about 3.8 billion years. (cont.)for about 3.8 billion years. (cont.) Relative ageRelative age is how old a rock oris how old a rock or fossil is compared to other rocksfossil is compared to other rocks or fossils. Ancient organismsor fossils. Ancient organisms settled to the bottom of a body ofsettled to the bottom of a body of water in layers of mud and sandwater in layers of mud and sand that later formed rock.that later formed rock.
  • 9. Absolute ageAbsolute age is the actual age ofis the actual age of the rock or fossil. To measure thethe rock or fossil. To measure the absolute age of a fossil, scientistsabsolute age of a fossil, scientists measure its radioactivity. Overmeasure its radioactivity. Over time, radioactive materialtime, radioactive material disappears. The older the fossil,disappears. The older the fossil, the less radioactive material itthe less radioactive material it has.has. Earth has been home to living thingsEarth has been home to living things for about 3.8 billion years. (cont.)for about 3.8 billion years. (cont.)
  • 10. Earth has been home to living thingsEarth has been home to living things for about 3.8 billion years. (cont.)for about 3.8 billion years. (cont.) TheThe fossil recordfossil record is all of theis all of the information that can be gatheredinformation that can be gathered from the fossils in a particularfrom the fossils in a particular location. Scientists can then uselocation. Scientists can then use the record to identify whichthe record to identify which species lived and died duringspecies lived and died during different periods of time.different periods of time.
  • 11. Earth has been home to living things forEarth has been home to living things for about 3.8 billion years. (cont.)about 3.8 billion years. (cont.) Unicellular organisms, made ofUnicellular organisms, made of only one cell, were the first livingonly one cell, were the first living things on Earth. They appearedthings on Earth. They appeared about 3.8 billion years ago. Theabout 3.8 billion years ago. The atmosphere then did not have asatmosphere then did not have as much oxygen as it does now.much oxygen as it does now. Some of the early organismsSome of the early organisms added oxygen to the atmosphere.added oxygen to the atmosphere.
  • 12. Earth has been home to living things forEarth has been home to living things for about 3.8 billion years. (cont.)about 3.8 billion years. (cont.) Multicellular organismsMulticellular organisms began to livebegan to live in Earth's oceans about 1.2 billionin Earth's oceans about 1.2 billion years ago. The fossil record showsyears ago. The fossil record shows that the earliest multicellularthat the earliest multicellular organisms were tiny seaweeds. Theorganisms were tiny seaweeds. The earliest animals were similar toearliest animals were similar to jellyfish.jellyfish.
  • 13. Earth has been home to living things forEarth has been home to living things for about 3.8 billion years. (cont.)about 3.8 billion years. (cont.)  Life appeared on land about 500 million yearsLife appeared on land about 500 million years ago. Before that, all living things met their needsago. Before that, all living things met their needs while living in water. Simple plants were the firstwhile living in water. Simple plants were the first land-dwelling organisms, getting water from theland-dwelling organisms, getting water from the soil through roots. The plants in turn providedsoil through roots. The plants in turn provided food and shelter to the first fungi and insects onfood and shelter to the first fungi and insects on land. After insects, amphibians and reptilesland. After insects, amphibians and reptiles began to live on land, followed by birds andbegan to live on land, followed by birds and mammals.mammals.
  • 14. Earth has been home to living things forEarth has been home to living things for about 3.8 billion years. (cont.)about 3.8 billion years. (cont.) A species becomes extinct whenA species becomes extinct when all members of the species haveall members of the species have died. Many species have onlydied. Many species have only been seen as fossils becausebeen seen as fossils because they became extinct long ago. Athey became extinct long ago. A mass extinction is a period whenmass extinction is a period when a large number of speciesa large number of species become extinct in a very shortbecome extinct in a very short time.time.
  • 15. Earth has been home to living things forEarth has been home to living things for about 3.8 billion years. (cont.)about 3.8 billion years. (cont.)  TheThe Permian ExtinctionPermian Extinction occurred aboutoccurred about 250 million years ago. Approximately 90250 million years ago. Approximately 90 percent of the species in the ocean, aspercent of the species in the ocean, as well as many land-dwelling animals,well as many land-dwelling animals, became extinct. This mass extinction maybecame extinct. This mass extinction may have been caused by climate change duehave been caused by climate change due to all of Earth's landmasses joiningto all of Earth's landmasses joining together to form a single, enormoustogether to form a single, enormous continent.continent.
  • 16. Example of Cretaceous ExtinctionExample of Cretaceous Extinction
  • 17. Earth has been home to living things forEarth has been home to living things for about 3.8 billion years. (cont.)about 3.8 billion years. (cont.) TheThe Cretaceous ExtinctionCretaceous Extinction occurred about 65 million yearsoccurred about 65 million years ago. More than half of all theago. More than half of all the species on Earth, includingspecies on Earth, including dinosaurs, became extinct. Thisdinosaurs, became extinct. This mass extinction may have beenmass extinction may have been caused by a meteorite, a giantcaused by a meteorite, a giant space object, colliding with Earth.space object, colliding with Earth.
  • 18. Earth has been home to living things forEarth has been home to living things for about 3.8 billion years. (cont.)about 3.8 billion years. (cont.) Mass extinctionsMass extinctions are oftenare often followed by the appearance of afollowed by the appearance of a large number of new species. Forlarge number of new species. For example, the extinction ofexample, the extinction of dinosaurs may have allowed newdinosaurs may have allowed new species of mammals to developspecies of mammals to develop and thrive.and thrive.
  • 19. Earth’s Change Over TimeEarth’s Change Over Time (Evolution)(Evolution) Species change over time.Species change over time.
  • 20. Species change over time.Species change over time. Evolution is the process by which species changeEvolution is the process by which species change over time.over time.  In the early 1800s, Jean-In the early 1800s, Jean- Baptiste de LamarckBaptiste de Lamarck proposed a theory ofproposed a theory of evolution. He suggestedevolution. He suggested that organisms developthat organisms develop traits during their livestraits during their lives and then pass them on toand then pass them on to offspring. For example, aoffspring. For example, a giraffe stretches its neckgiraffe stretches its neck to get high leaves, andto get high leaves, and then passes that longerthen passes that longer neck to the nextneck to the next generation. But Lamarckgeneration. But Lamarck could not find evidence tocould not find evidence to support his theory.support his theory.
  • 21. Species change over time.Species change over time. Evolution is the process by which species changeEvolution is the process by which species change over time.over time.  Charles Darwin was aCharles Darwin was a naturalist who traveled to thenaturalist who traveled to the Galapagos Islands in the lateGalapagos Islands in the late 1830s. Darwin's theory of1830s. Darwin's theory of evolution developed fromevolution developed from observing different species ofobserving different species of tortoises and finches on thetortoises and finches on the Galapagos Islands. ForGalapagos Islands. For example, he found someexample, he found some finches with beaks useful forfinches with beaks useful for cracking seeds and others withcracking seeds and others with beaks useful for capturingbeaks useful for capturing insects. Darwin wonderedinsects. Darwin wondered whether the birds had evolvedwhether the birds had evolved differently because they weredifferently because they were in different environments.in different environments.
  • 22. Species change over timeSpecies change over time..  A group of organisms may evolve due toA group of organisms may evolve due to artificial selectionartificial selection  artificial selectionartificial selection is the process thatis the process that breeders use to produce animals withbreeders use to produce animals with desirable traits. A breeder will selectdesirable traits. A breeder will select individuals with desired traits from aindividuals with desired traits from a group, then allow only those individuals togroup, then allow only those individuals to mate. In the next generation, the breedermate. In the next generation, the breeder will again select the individuals withwill again select the individuals with desired traits and mate them to producedesired traits and mate them to produce the next generation.the next generation.
  • 23. Species change over timeSpecies change over time.. Natural SelectionNatural Selection  Natural selectionNatural selection is the hypothesis Darwinis the hypothesis Darwin developed based on his observations fromdeveloped based on his observations from his voyage and from his hobby of breedinghis voyage and from his hobby of breeding pigeons. Darwin proposed that memberspigeons. Darwin proposed that members of a species that are best suited to theirof a species that are best suited to their environment survive and reproduce at aenvironment survive and reproduce at a higher rate than other members of thehigher rate than other members of the species. This process is called naturalspecies. This process is called natural selection.selection.
  • 24. Species change over time.Species change over time. The process of natural selection depends on a fewThe process of natural selection depends on a few key principles.key principles.  OverproductionOverproduction is theis the idea that mostidea that most organisms produceorganisms produce more offspring thanmore offspring than can possibly survive.can possibly survive. For example, aFor example, a female salmon laysfemale salmon lays thousands of eggs,thousands of eggs, but only severalbut only several dozen will survive todozen will survive to adulthood, and evenadulthood, and even fewer will reproduce.fewer will reproduce.
  • 25. The process of natural selection depends on a fewThe process of natural selection depends on a few key principles.key principles.  VariationVariation is the naturalis the natural differences in traitsdifferences in traits among the members of aamong the members of a species. Some mightspecies. Some might have slightly larger fins,have slightly larger fins, others different patternsothers different patterns of spots. Mutations areof spots. Mutations are changes in geneticchanges in genetic material that cause amaterial that cause a variation. Variations, duevariation. Variations, due either to mutation or theeither to mutation or the random combination ofrandom combination of genes from parents, aregenes from parents, are passed from onepassed from one generation to the next.generation to the next.
  • 26. Species change over time.Species change over time. The process of natural selection depends on a fewThe process of natural selection depends on a few key principles.key principles.  AnAn adaptationadaptation is anyis any inherited trait that givesinherited trait that gives an organism anan organism an advantage in its particularadvantage in its particular environment. Anenvironment. An adaptation is a variationadaptation is a variation that makes an individualthat makes an individual better able to survive thanbetter able to survive than others. For example, aothers. For example, a slight change in theslight change in the shape of a fin might makeshape of a fin might make a fish swim faster anda fish swim faster and avoid predators.avoid predators.
  • 27. Species change over time.Species change over time. The process of natural selection depends on a fewThe process of natural selection depends on a few key principles.key principles.  SelectionSelection is the processis the process that passes the mostthat passes the most successful variations, orsuccessful variations, or adaptations, into the nextadaptations, into the next generation. Of thegeneration. Of the organisms that thenorganisms that then survive to reproduce,survive to reproduce, more and more of themmore and more of them will have the adaptation.will have the adaptation. The favorable traits areThe favorable traits are "selected" for the next"selected" for the next generations. In this way,generations. In this way, the species as a wholethe species as a whole becomes more suited tobecomes more suited to its environment.its environment.
  • 28. Species change over time.Species change over time. The process of natural selection depends on a fewThe process of natural selection depends on a few key principles.key principles.  SpeciationSpeciation is the evolution of a new species fromis the evolution of a new species from an existing species. Speciation can occur whenan existing species. Speciation can occur when the environment changes. When geneticthe environment changes. When genetic changes within two groups of the same specieschanges within two groups of the same species build up, the two groups may not be able tobuild up, the two groups may not be able to interbreed anymore. When this happens, twointerbreed anymore. When this happens, two different species have formed and speciationdifferent species have formed and speciation has occurred. The diagrams show how threehas occurred. The diagrams show how three species of cichlid fish evolved from one originalspecies of cichlid fish evolved from one original species in Lake Tanganyika.species in Lake Tanganyika.
  • 29. Species change over time.Species change over time. The process of natural selection depends on a fewThe process of natural selection depends on a few key principles.key principles.  IsolationIsolation is essential to speciation. For a speciesis essential to speciation. For a species to separate, two groups must be prevented fromto separate, two groups must be prevented from reproducing with one another. A geographicreproducing with one another. A geographic boundary, such as a mountain range or ocean,boundary, such as a mountain range or ocean, can result in isolation. The cichlids in Lakecan result in isolation. The cichlids in Lake Tanganyika and the finches Darwin observed inTanganyika and the finches Darwin observed in the Galapagos Islands are examples of isolationthe Galapagos Islands are examples of isolation leading to new species.leading to new species.
  • 30. Earth’s Change Over TimeEarth’s Change Over Time (Evolution)(Evolution)  Many types of evidenceMany types of evidence support evolution.support evolution.
  • 31. Many types of evidence supportMany types of evidence support evolution.evolution. AA theorytheory is a widely acceptedis a widely accepted statement, based on scientificstatement, based on scientific evidence, that helps explain aevidence, that helps explain a group of facts. Darwin's theory ofgroup of facts. Darwin's theory of evolution is widely acceptedevolution is widely accepted because it is supported by fossilbecause it is supported by fossil evidence, biological evidence,evidence, biological evidence, and genetic evidence.and genetic evidence.
  • 32. Many types of evidenceMany types of evidence support evolution.support evolution.  Evidence from fossils supports evolution.Evidence from fossils supports evolution. An ancestor is an early form of anAn ancestor is an early form of an organism from which later forms descend.organism from which later forms descend. According to the theory of evolution,According to the theory of evolution, different species should have commondifferent species should have common ancestors. Fossil evidence supports thisancestors. Fossil evidence supports this idea. For example, modern plants andidea. For example, modern plants and modern algae share characteristics withmodern algae share characteristics with fossil algae that point to a commonfossil algae that point to a common
  • 33. Many types of evidenceMany types of evidence support evolution.support evolution. Biological evidence supportsBiological evidence supports evolution. Biological evidenceevolution. Biological evidence includes the structure of livingincludes the structure of living things and how living thingsthings and how living things develop into adults.develop into adults.
  • 34. Many types of evidenceMany types of evidence support evolution.support evolution.  Vestigial organsVestigial organs areare physical structures thatphysical structures that were fully developed andwere fully developed and functional in an earlierfunctional in an earlier group of organisms butgroup of organisms but are reduced and unusedare reduced and unused in later species. Thesein later species. These vestigial organs indicatevestigial organs indicate that the organism had anthat the organism had an ancestor that needed theancestor that needed the trait, and can show howtrait, and can show how the modern organism andthe modern organism and the ancestor are related.the ancestor are related.
  • 35. Many types of evidenceMany types of evidence support evolution.support evolution.  Similar structuresSimilar structures with different functions indicate thatwith different functions indicate that organisms shared a common ancestor. For example, theorganisms shared a common ancestor. For example, the illustrations show that geckos, bats, and manatees haveillustrations show that geckos, bats, and manatees have similar bones in their forelimb. A shorter bone leads fromsimilar bones in their forelimb. A shorter bone leads from the shoulder to a joint. From the joint, the longer bonethe shoulder to a joint. From the joint, the longer bone leads to a wrist. Because the three organisms live in veryleads to a wrist. Because the three organisms live in very different environments, the similar structures havedifferent environments, the similar structures have evolved in very different ways.evolved in very different ways.
  • 36. Many types of evidenceMany types of evidence support evolution.support evolution.  Similarities in development of different species that areSimilarities in development of different species that are unlike as adults indicate a common ancestor. Forunlike as adults indicate a common ancestor. For example, a chicken, a rabbit, and a salamander areexample, a chicken, a rabbit, and a salamander are three very different animals. However, their embryosthree very different animals. However, their embryos look very similar. As the embryos develop, they becomelook very similar. As the embryos develop, they become more different. This evidence indicates that manymore different. This evidence indicates that many animals must share a common ancestor whose embryoanimals must share a common ancestor whose embryo started developing in a similar way.started developing in a similar way.
  • 37. Many types of evidenceMany types of evidence support evolutionsupport evolution Genetic evidenceGenetic evidence supports the theory ofsupports the theory of evolution.evolution.
  • 38. Many types of evidenceMany types of evidence support evolutionsupport evolution DNA contains the genetic materialDNA contains the genetic material found in all cells. It contains a codefound in all cells. It contains a code that a cell uses to function properly.that a cell uses to function properly. The code is a pattern of four chemicalThe code is a pattern of four chemical units called bases, represented by theunits called bases, represented by the letters A, T, C, and G.letters A, T, C, and G.
  • 39. Many types of evidenceMany types of evidence support evolution.support evolution.  GenesGenes are segments of DNA that relate to aare segments of DNA that relate to a specific trait or function of an organism. Forspecific trait or function of an organism. For example, the clock gene is found in manyexample, the clock gene is found in many mammals and relates to how the mammalmammals and relates to how the mammal sleeps and wakes. The clock gene can be usedsleeps and wakes. The clock gene can be used to compare different organisms. The moreto compare different organisms. The more similar the code is for the clock gene betweensimilar the code is for the clock gene between two organisms, the more closely related the twotwo organisms, the more closely related the two organisms are.organisms are.
  • 40. The EndThe End

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