Life’s

Record

Early EarthEarly Earth

• Early earth was most Early earth was most likely very hot with lots likely very hot with lots of lava flow. Only of lava flow. Only Archea bacteria would Archea bacteria would have been able to have been able to survive in the early survive in the early earth conditions.earth conditions.

• Gases coming from Gases coming from violent eruptions violent eruptions helped create earth’s helped create earth’s atmosphere, such as atmosphere, such as water vapor, carbon water vapor, carbon dioxide, and nitrogen.dioxide, and nitrogen.

FossilsFossils

• Evidence of an Evidence of an organism that lived in organism that lived in the past.the past.

• Types Types Trace fossilsTrace fossils

CastsCasts ImprintsImprints PetrifiedPetrified MoldsMolds

Amber preserved and Amber preserved and frozen fossils.frozen fossils.

http://biology.st-and.ac.uk/sites/bellpet/fossils.jpg

Fossilization ProcessFossilization Process

• Animal diesAnimal dies

• Gets covered by dirt/ Gets covered by dirt/ sediments.sediments.

• Over time, layers and Over time, layers and layers build up on layers build up on remains.remains.

• Earth movements Earth movements reveal remains, and reveal remains, and they are found.they are found.

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Who are Paleontologists?Who are Paleontologists?

• Scientists who study fossils.Scientists who study fossils.

• By studying fossils, these scientists By studying fossils, these scientists gain insight into what the past was gain insight into what the past was like, what creatures lived at different like, what creatures lived at different times, and by doing this they times, and by doing this they construct the construct the

Geologic Time Scale.

Dating FossilsDating Fossils

• Relative DatingRelative Dating– Fossils at the top of layers of earth are younger than Fossils at the top of layers of earth are younger than

those at the bottom.those at the bottom.– This is a geological lawThis is a geological law– Can’t be used to tell specific age of fossilCan’t be used to tell specific age of fossil

• Radiometric DatingRadiometric Dating– Done by using the decay rate of radioactive isotopes, Done by using the decay rate of radioactive isotopes,

the the Half Life Half Life [the time it takes for half of the material to [the time it takes for half of the material to decay]decay]

– Most common used are:Most common used are:• Potassium 40, half life=1.3 billion yrs [older fossils}Potassium 40, half life=1.3 billion yrs [older fossils}• Carbon 14, Half Life=5730 yrs [fossils less than 50,000 yrs Carbon 14, Half Life=5730 yrs [fossils less than 50,000 yrs

old]old]

Early IdeasEarly Ideas

• Spontaneous Spontaneous GenerationGeneration– Idea that nonliving Idea that nonliving

material could form life.material could form life.– Redi’s and Pastuer’s Redi’s and Pastuer’s

experiments disproved experiments disproved this idea.this idea.• Redi experimented with Redi experimented with

flies, maggots, and flies, maggots, and meat.meat.

• Pastuer experimented Pastuer experimented with broth.with broth.

• BiogenesisBiogenesis– Living organisms can Living organisms can

come only from other come only from other living organismsliving organisms

http://www.slic2.wsu.edu:82/hurlbert/micro101/images/hist9.gif

http://biology.clc.uc.edu/graphics/bio104/redi.jpg

Evolution of LifeEvolution of Life

• Two developments that preceded Two developments that preceded appearance of life on Earth:appearance of life on Earth:– Simple organic molecules formSimple organic molecules form– These molecules organized into complex These molecules organized into complex

organic molecules (proteins, carbs, nucleic organic molecules (proteins, carbs, nucleic acids)acids)

• Protocells then formedProtocells then formed– Large, ordered structures enclosed in a Large, ordered structures enclosed in a

membrane. It carried out some basic life membrane. It carried out some basic life functions such as growth and division.functions such as growth and division.

Evolution of cellEvolution of cell

• First true cellsFirst true cells– Possibly prokaryotes that evolved from Possibly prokaryotes that evolved from

protocells.protocells.– Were probably heterotrophs (feeding off of Were probably heterotrophs (feeding off of

other things, such as organic molecules)other things, such as organic molecules)

• Autotrophs evolved (photosynthesis Autotrophs evolved (photosynthesis begins), thus increasing concentration begins), thus increasing concentration of Oof O2 2 in atmosphere.in atmosphere.

http://images.google.com/imgres?imgurl=www.siu.edu/~protocell/photos/siu1.gif&imgrefurl=http://www.siu.edu/~protocell/photos2.htm&h=605&w=482&prev=/images%3Fq%3Dprotocell%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8

Endosymbiont TheoryEndosymbiont Theory

• Proposed by Lynn Margulis in 1960’sProposed by Lynn Margulis in 1960’s• Proposes that:Proposes that:

– Eukaryotes evolved through a symbiotic Eukaryotes evolved through a symbiotic relationship with prokaryotes (sharing)relationship with prokaryotes (sharing)

– Anerobic bacteria was engulfed (Anerobic bacteria was engulfed (phagocytosisphagocytosis) ) and became chloroplasts.and became chloroplasts.

– Evidence for this is:Evidence for this is:• Both chloroplasts and mitochondria contain their own Both chloroplasts and mitochondria contain their own

DNA that is similar to that of prokaryotesDNA that is similar to that of prokaryotes• Size of these organelles is equivalent or similar to Size of these organelles is equivalent or similar to

that of prokaryotesthat of prokaryotes• That these organelles are membrane boundThat these organelles are membrane bound

http://www.mrs.umn.edu/~goochv/CellBio/lectures/endo/Image157.gif

The Theory of The Theory of EvolutionEvolution

What is EVOLUTION anyway?What is EVOLUTION anyway?

• Evolution is Evolution is changechange in a in a population over population over time.time.

• The word itself The word itself refers to refers to CHANGECHANGE..

Charles DarwinCharles Darwin• Proposed the theory of Proposed the theory of

evolution by evolution by natural natural selectionselection..

• He came up with this theory He came up with this theory through studying nature through studying nature during his voyage on the during his voyage on the HMS HMS BeagleBeagle..

• During this voyage he During this voyage he explored life on the explored life on the Galapagos IslandsGalapagos Islands..

• He studied the large He studied the large tortoises that are found tortoises that are found there.there.

• Natural selectionNatural selection was was proposed to explain how proposed to explain how species changed over time.species changed over time.

http://academy.d20.co.edu/kadets/lundberg/darwin/darwin.JPG

http://www.victory-cruises.com/graphics/BEAGLE.gif

DarwinDarwin’’s Experimentss Experiments

• He bred pigeons and studied traits the He bred pigeons and studied traits the population inherited.population inherited.

• By doing this he was using By doing this he was using artificial artificial selectionselection (breeding for specific (breeding for specific traits).traits).

• He studied the traits that were He studied the traits that were passed down from the parent passed down from the parent generation and looked at how they generation and looked at how they adapted to specific adapted to specific selective forcesselective forces (things that cause adaptation).(things that cause adaptation).

How does Natural Selection How does Natural Selection work?work?

• Different things happen to the Different things happen to the environment that cause species environment that cause species to be forced to adapt. The ones to be forced to adapt. The ones that survive reproduce and pass that survive reproduce and pass on the on the selected forselected for traits. traits.

• These traits enable the offspring These traits enable the offspring to survive until the environment to survive until the environment changes and forces new traits to changes and forces new traits to be be selected forselected for..

Adaptations: Take Time!!Adaptations: Take Time!!

• Adaptations are evidence for Adaptations are evidence for evolution. But these adaptations take evolution. But these adaptations take time, and normally take a few time, and normally take a few generations. generations.

• There are two different adaptations There are two different adaptations – Structural Structural – PhysiologicalPhysiological

Structural AdaptationsStructural Adaptations• Common examples are teeth size, Common examples are teeth size,

claw size, ect…claw size, ect…• More specificallyMore specifically

– MimicryMimicry, this structural adaptation , this structural adaptation enables one animal to look like enables one animal to look like another. This may be used to another. This may be used to resemble a dangerous animal for resemble a dangerous animal for protection, or used by predators to protection, or used by predators to capture prey.capture prey.

– CamouflageCamouflage, enables animals to , enables animals to blend in with their surroundings, blend in with their surroundings, helps in avoiding predatorshelps in avoiding predators..

http://www.msmedia.com.au/Science/images/mimicry.jpg

http://students.washington.edu/cochranb/hawaii/camouflage.jpg

Physiological AdaptationsPhysiological Adaptations

• These changes occur in the These changes occur in the organism’s organism’s metabolismmetabolism..

• One example is the quick One example is the quick adaptations of bacteria to the adaptations of bacteria to the lethal affect of penicillin, in lethal affect of penicillin, in other words they are becoming other words they are becoming immuneimmune, requiring higher and , requiring higher and higher doses to kill bacteria.higher doses to kill bacteria.

• Another example is increased Another example is increased pesticide resistance in plants pesticide resistance in plants and insects.and insects.

• http://forum1.sewanee.edu/palisano/http://forum1.sewanee.edu/palisano/wastewater/images/ecoli.jpgwastewater/images/ecoli.jpg

Other Other Evolution Evolution EvidenceEvidence

• Fossil record show signs of evolutionFossil record show signs of evolution• Anatomy of organismsAnatomy of organisms

– Homologous structuresHomologous structures, structures similar in , structures similar in arrangement, function, or both. This is evidence of arrangement, function, or both. This is evidence of evolution from a common ancestor.evolution from a common ancestor.

– Analogous structuresAnalogous structures, body structures that do not , body structures that do not have a common origin, but that are similar in function.have a common origin, but that are similar in function.

– Vestigial structureVestigial structure, a body structure that has no , a body structure that has no function, it is thought to be retained from evolutionary function, it is thought to be retained from evolutionary ancestor through heredity. ancestor through heredity.

Evidence continuedEvidence continued

• EmbryologyEmbryology– This deals with the similarities This deals with the similarities

in embryos (the first stage of in embryos (the first stage of life) of different species. life) of different species.

• BiochemistryBiochemistry– This uses the comparisons of This uses the comparisons of

DNA or RNA of different DNA or RNA of different species to show evolutionary species to show evolutionary relationship.relationship.

http://www.cord.edu/faculty/landa/courses/b315f99/sessions/phylogeny/embryology.jpg

Primate EvolutionPrimate Evolution

What are Primates?What are Primates?

• They are a group of They are a group of mammals.mammals.

• This group includes This group includes lemurs, monkeys, lemurs, monkeys, apes, and humans.apes, and humans.

• They come in all They come in all different shapes and different shapes and sizes.sizes.

Common Characteristics of Common Characteristics of PrimatesPrimates• They all have opposable thumbs.They all have opposable thumbs.

• Their brain volume is large compared Their brain volume is large compared to their body size.to their body size.

• Vision is the dominant sense, Vision is the dominant sense, binocular vision.binocular vision.

• Arms adapted for a great range of motion.Arms adapted for a great range of motion.

• Flexible jointsFlexible joints

• Feet are able to grasp thingsFeet are able to grasp things..

How did they evolve?How did they evolve?

• Scientist use fossils, Scientist use fossils, comparative anatomical comparative anatomical features (body similarities), features (body similarities), and DNA to propose and DNA to propose evolution ideas.evolution ideas.

• Prosimians Prosimians evolved first. evolved first. – These were small present These were small present

day primates such as lemurs.day primates such as lemurs.

Anthropoids Evolve...Anthropoids Evolve...

• Anthropoids Anthropoids are are humanlike humanlike primates.primates.

• They evolved after They evolved after the prosimians.the prosimians.

• They includes apes They includes apes and humans.and humans.

http://www.mosartdesigns.on.ca/largeart/paintings-ape.jpg

Differences of AnthropoidsDifferences of Anthropoids

• They have more complex brains than They have more complex brains than prosimians.prosimians.

• Larger and different skeletal features Larger and different skeletal features (more upright posture)(more upright posture)

• Examples are Gibbons, orangutans, Examples are Gibbons, orangutans, chimpanzees, and gorillas.chimpanzees, and gorillas.

Old World and New World Old World and New World MonkeysMonkeys

• These are two classes monkeys are These are two classes monkeys are broken up into.broken up into.

• Old world are generally larger, and may Old world are generally larger, and may be terrestrial.be terrestrial.

• New World live in South and Central New World live in South and Central America.America.

• They are all Arboreal (living in the trees) They are all Arboreal (living in the trees) and have long, muscular and have long, muscular prehensile tail.prehensile tail.

Humans tied inHumans tied in

• Scientist theorize Scientist theorize that we were the that we were the last to evolve.last to evolve.

• We have an even We have an even larger brain larger brain capacity and walk capacity and walk upright.upright.

http://www.bio.psu.edu/faculty/hedges/primate.gif

Hominoid EvolutionHominoid Evolution

• HominoidsHominoids or humans began to evolve in or humans began to evolve in Asia and Africa as the fossil records Asia and Africa as the fossil records shows us.shows us.

• Hominoids include apes and humans.Hominoids include apes and humans.

• Scientists think that gibbons were the Scientists think that gibbons were the first to evolve, then orangutans, followed first to evolve, then orangutans, followed by the African apes, chimpanzees, and by the African apes, chimpanzees, and gorillas. One of these being or possible gorillas. One of these being or possible ancestor.ancestor.

Human AncestryHuman Ancestry

• Scientist believe that there were two lines Scientist believe that there were two lines evolving. One being humans, and the other were evolving. One being humans, and the other were the African apes- gorillas and chimpanzees.the African apes- gorillas and chimpanzees.

• Bipedal Bipedal adaptation of humans sets us apart. adaptation of humans sets us apart. (walking upright)(walking upright)

http://www.centerfortheperson.org/HUMAN%20EVOLUTION.jpg

Time line of evolutionTime line of evolution

Australopithecus afarensis

Homo sapiens

Homo erectus

Homo habilis

A. boiseri A. robustus

Australopithecus africanus

Development of cultureDevelopment of culture

• The first known humanoid The first known humanoid fossils was fossils was australopithecineaustralopithecine..

• Next came the Next came the Neanderthals Neanderthals who lived in Europe, Asia, who lived in Europe, Asia, and the middle East 35000-and the middle East 35000-100000 yrs ago.100000 yrs ago.

• Cro-Magnons Cro-Magnons then became then became the most recent modern the most recent modern human ancestor.human ancestor.

http://cator.hsc.edu/~kmd/caveman/shanidar.jpg

Neanderthals & Cro-Neanderthals & Cro-MagnonsMagnons• NeanderthalsNeanderthals were the first humanoids were the first humanoids

to use tools for hunting and to use fire.to use tools for hunting and to use fire.

• Through them a semblance of culture Through them a semblance of culture developed.developed.

• Cro-Magnons Cro-Magnons further developed the further developed the use of language and art, primarily use of language and art, primarily cave drawings. They also advanced cave drawings. They also advanced tool making.tool making.