Fossil EvidenceFossil Evidence

Fossils-Fossils- a any traces of dead organismsny traces of dead organisms dinosaur bonesdinosaur bones insects trapped in tree sapinsects trapped in tree sap leaf impressionsleaf impressions footprintsfootprints

Fossil EvidenceFossil Evidence Transitional speciesTransitional species- - species that have been species that have been

found in the fossil record that are found in the fossil record that are intermediates between two other species in intermediates between two other species in the evolutionary process.the evolutionary process.

Radiometric datingRadiometric dating-- a dating technique that measures amount a dating technique that measures amount of radioactive material in a rock or fossil.of radioactive material in a rock or fossil.

Relative dating-Relative dating- a dating technique that estimates the date of a dating technique that estimates the date of a fossil by relating it to the age of the layers of rock around it.a fossil by relating it to the age of the layers of rock around it.

Fossil EvidenceFossil Evidence

To fossilize an organism To fossilize an organism must be buried by must be buried by sedimentsediment. .

In swamps, mud, tar pits, In swamps, mud, tar pits, or the ocean bottom.or the ocean bottom.

Hard stuff fossilizes Hard stuff fossilizes (bones, nails). (bones, nails).

Radiometric and relative Radiometric and relative dating are used to find out dating are used to find out how old the fossil is.how old the fossil is.

Relative Dating

RadiometricDating

Fossil EvidenceFossil Evidence Fossils show:Fossils show:

Life has been around for millions of yearsLife has been around for millions of years Transitional species link older to newer speciesTransitional species link older to newer species

Darwin proposed the idea of transitional species, Darwin proposed the idea of transitional species, though he had no evidencethough he had no evidence

Today we have evidence:Today we have evidence:• ArchaeopteryxArchaeopteryx• WhalesWhales

Fossil Evidence-ArchaeopteryxFossil Evidence-Archaeopteryx

BEAK

WINGS

Fossil EvidenceFossil Evidence

Whales--60 million years of evolutionWhales--60 million years of evolution Descended from 4-legged wolf-like Descended from 4-legged wolf-like

animals that were also ancestors to animals that were also ancestors to cows and horsescows and horses

Fossil evidence shows slow loss of legsFossil evidence shows slow loss of legs Pelvis still remains with no rear legsPelvis still remains with no rear legs

Fossil Evidence-WhalesFossil Evidence-Whales

Whale Video

Earth is estimated to be about 4.6 billion Earth is estimated to be about 4.6 billion years old.years old.

Atmosphere was harsh.Atmosphere was harsh. Very Hot.Very Hot. Lots of water vapor Lots of water vapor VolcanoesVolcanoes NO BREATHABLE OXYGEN GAS!NO BREATHABLE OXYGEN GAS! COCO22, ammonia, methane present, ammonia, methane present

Origin of LifeOrigin of Life Scientists had hard time Scientists had hard time

finding evidence of early finding evidence of early life.life.

45 years ago we found out 45 years ago we found out why….why….

Most ancient life was Most ancient life was microscopic=microfossils in microscopic=microfossils in stromatolites.stromatolites.

11stst organisms to evolve organisms to evolve were prokaryotes were prokaryotes

Oldest microfossilOldest microfossil3.5 3.5 billion years old billion years old

Cyanobacteria fossil about 1,000,000,000 (1 billion) years old found in stromatolites

Stromatolites

Origin of LifeOrigin of Life’’s Chemicalss Chemicals Miller-UreyMiller-Urey Hypothesis: Can organic Hypothesis: Can organic

compounds form in early compounds form in early Earth conditions?Earth conditions?

Experiment recreated Experiment recreated atmosphere of early Earthatmosphere of early Earth

Results: building blocks of Results: building blocks of life were formed. life were formed. Amino acids (proteins)Amino acids (proteins) Nucleotides (DNA, RNA)Nucleotides (DNA, RNA) LipidsLipids CarbohydratesCarbohydrates

Self AssemblySelf Assembly Some molecules can Some molecules can

spontaneously form into spontaneously form into droplets droplets

Solution with lipids and Solution with lipids and proteins will self assemble proteins will self assemble into a lipid bilayer like a cell into a lipid bilayer like a cell membranemembrane

First cell membrane and First cell membrane and beginning of prokaryotic life beginning of prokaryotic life took 1 billion years.took 1 billion years.

What else is needed for life?What else is needed for life?

11stst genetic material- RNA genetic material- RNA

EarthEarth’’s early surface was inhospitable s early surface was inhospitable due to immense UV radiationdue to immense UV radiation

Deep sea vents may have provided Deep sea vents may have provided sheltered location for life. sheltered location for life.

Oldest living prokaryotes found there Oldest living prokaryotes found there today…today…

RNA can form under conditions similar RNA can form under conditions similar to deep sea ventsto deep sea vents

Road to Modern OrganismsRoad to Modern Organisms11stst life was bacteria life was bacteria unicellular prokaryotes unicellular prokaryotes

CyanobacteriaCyanobacteria- photosynthetic blue-green prokaryotes - photosynthetic blue-green prokaryotes later changed Earthlater changed Earth’’s atmospheres atmospherereleased Oreleased O22! !

22ndnd was unicellular eukaryotes was unicellular eukaryotes Endosymbiotic Endosymbiotic TheoryTheory

33rdrd was multicellular organisms was multicellular organisms

Classification/EvolutionClassification/Evolution6 Kingdoms6 Kingdoms

Classifying Living ThingsClassifying Living Things Carl Linnaeus was a Carl Linnaeus was a

scientist who developed a scientist who developed a classification system for classification system for living things.living things.

Wrote book Wrote book Systema Systema NaturaeNaturae in 1735 to in 1735 to reveal his classification reveal his classification system.system.

How biologists classifyHow biologists classify

1. 1. Comparing morphology Comparing morphology (physical traits)(physical traits)

2. Looking at genetic 2. Looking at genetic similarities & differencessimilarities & differences

3. Biochemical make-ups3. Biochemical make-ups 4. Behavioral similarities4. Behavioral similarities Origin of Life Video

CladogramsCladograms CladogramCladogram- a branching diagram that shows - a branching diagram that shows

evolutionary relationships. evolutionary relationships. We use We use taxonomytaxonomy – the science of classifying – the science of classifying

living things, to help us determine the living things, to help us determine the cladogram.cladogram.

Scientific NamingScientific Naming

Binomial nomenclature-Binomial nomenclature- unique 2-word unique 2-word naming system used by scientists.naming system used by scientists.

11stst word is the genus, 2 word is the genus, 2ndnd is the species. is the species. GenusGenus- group of organisms that share similar - group of organisms that share similar

characteristics.characteristics. Panthera leo-Panthera leo-lionlion Panthera pardus-leopardPanthera pardus-leopard

SpeciesSpecies- group of organisms that can - group of organisms that can successfully breed within their group, but not successfully breed within their group, but not others.others.

How to write a scientific How to write a scientific namename

Genus is always capitalizedGenus is always capitalized Species is always lower Species is always lower

casecase The whole name is The whole name is

underlined if written or underlined if written or italicized if typed.italicized if typed.

Example: Example: Homo sapiensHomo sapiens

ExamplesExamples Homo sapiensHomo sapiens::

HomoHomo = genus = genus sapienssapiens = species = species Common name = humansCommon name = humans

Quercus rubraQuercus rubra–– Quercus = Quercus = genusgenus rubra = rubra = speciesspecies Common name = red oakCommon name = red oak

Scientific names are in Latin b/c scholars in the Scientific names are in Latin b/c scholars in the Middle Ages communicated using it!Middle Ages communicated using it!

6 Kingdoms6 Kingdoms There are six kingdoms all living There are six kingdoms all living

things are classified into:things are classified into: AnimalsAnimals PlantsPlants FungiFungi ProtistsProtists EubacteriaEubacteria Archeabacteria Archeabacteria

ClassificationClassification Scientists have determined Scientists have determined

seven levels of classification: seven levels of classification: KingKingdom = dom = KKingingss PPhylum = hylum = PPassass ClassClass = = ClassClasseses OrderOrder = to = to OrderOrder FamilFamilyy = = FamilFamiliesies GGenus = and their enus = and their GGood ood SSpecies = pecies = SSons aroundons around

Classification of Modern Classification of Modern HumansHumans

Kingdom = AnimaliaKingdom = Animalia Phylum = ChordataPhylum = Chordata Class = MammaliaClass = Mammalia Order = Primates Order = Primates Family = HominidaeFamily = Hominidae Genus = Genus = HomoHomo Species = Species = sapienssapiens

Evolution of PrimatesEvolution of PrimatesPrimate-Primate- mammal with 5 flexible mammal with 5 flexible fingersfingers

Earliest dwelled in trees-Earliest dwelled in trees-arborealarboreal

Needed special adaptations for Needed special adaptations for this:this:– Opposable thumb….Why?Opposable thumb….Why?– Binocular vision-Binocular vision- eyes in front eyes in front

of head in which field of vision of head in which field of vision of eyes overlap—depth of eyes overlap—depth perception….Why?perception….Why?

– Rotating ShouldersRotating Shoulders

Evolution of HumansEvolution of HumansVocab:Vocab:– BipedalBipedal- walk upright on two legs- walk upright on two legs– HominidHominid- bipedal primates such as - bipedal primates such as

humans and their closest fossil relativeshumans and their closest fossil relatives

HominidsHominidsHominids are the ONLY bipedal primates:Hominids are the ONLY bipedal primates:– Locking knee jointsLocking knee joints– Spine enters skull atSpine enters skull at

bottom of headbottom of head– Femurs (thigh bone)Femurs (thigh bone)

tapers intapers in– Big toe in line with Big toe in line with

othersothersLaetoli Footprints

Hominid vs. chimpanzeeHominid vs. chimpanzee

Chimps most closely related primate to Chimps most closely related primate to humans—95% similarity in the sequence of humans—95% similarity in the sequence of our genes!our genes!

HumanHuman’’s jaw arc shaped with smaller s jaw arc shaped with smaller canines; chimpscanines; chimps’’ are U shaped with larger are U shaped with larger canines and larger gaps.canines and larger gaps.

Hominid vs. chimpanzeeHominid vs. chimpanzee

Hominid spine S– Hominid spine S– chimpschimps’’ is C shaped is C shaped

Hominid pelvis is Hominid pelvis is bowl-shaped, chimpsbowl-shaped, chimps’’ longlong

Hominid thigh bones Hominid thigh bones taper in—chimpstaper in—chimps’’ out out

Human Evolution Human Evolution Video ClipVideo Clip

Early HominidsEarly HominidsGenus Genus AustralopithecusAustralopithecus– LucyLucyAustralopithecus afarensisAustralopithecus afarensis– Fossil found in AfricaFossil found in Africa– They were hominidsThey were hominids

Shape of pelvis and femurs showed Shape of pelvis and femurs showed they were bipedal. they were bipedal.

Locking knee jointsLocking knee joints

– Short—3Short—3’’66’’’’– Brain size of chimpsBrain size of chimps– Jaws more rounded than apesJaws more rounded than apes– Teeth like humansTeeth like humans

LUCYLUCY3.5 million years old3.5 million years old

40% complete40% complete

FemaleFemale

Showed us:Showed us:– Walked upright firstWalked upright first– Brain size grew Brain size grew

LATER.LATER.

SKULLSSKULLS

A. afarensis (Lucy) Homo sapienA. afarensis (Lucy) Homo sapien

SKULLSSKULLS Lucy had a small skull like an ape, but she wasnLucy had a small skull like an ape, but she wasn’’t one.t one.

LUCY APELUCY APE

LUCY VS. APELUCY VS. APE

Homo habilisHomo habilisMeans: Handy manMeans: Handy man

Small structure like Small structure like LucyLucy

Skull 2XSkull 2X’’s the size s the size of Lucyof Lucy

2- 1.8 mya in Africa2- 1.8 mya in Africa

Tools made of bone Tools made of bone and stone. and stone.

Homo erectusHomo erectus

Peking manPeking manAfrica / Asia / EuropeAfrica / Asia / EuropeLarger than H. habilisLarger than H. habilisLarger brainLarger brainExcellent tools, used fireExcellent tools, used fire1.5 mya – 1.5 mya – ““immediateimmediate”” ancestorancestor

Where Did Where Did H. sapiensH. sapiens evolve? evolve?

Out of Africa Out of Africa hypthothesis-hypthothesis- idea idea like Darwinlike Darwin’’s which s which states states H. sapiensH. sapiens evolved IN Africa and evolved IN Africa and spread to rest of spread to rest of worldworld

Out of Africa Out of Africa hypothesis supported hypothesis supported by fossils of modern-by fossils of modern-like humans found in like humans found in AfricaAfrica

H..sapiens

H. erectus

Early Early H. sapiensH. sapiens

Homo neanderthalensis -Homo neanderthalensis -discovered in Neander Valley discovered in Neander Valley in Belgiumin Belgium

Massive skulls and Massive skulls and

protruding brows protruding brows

400,000-100,000 years ago400,000-100,000 years ago

Early Early H. sapiensH. sapiensGreat controversy: did Great controversy: did

they die off (genes no they die off (genes no longer) or did they longer) or did they interbreed with us so their interbreed with us so their genes are still in our gene genes are still in our gene pool?pool?

Modern Modern H. sapiensH. sapiens probably evolved in Africa probably evolved in Africa and replaced Neanderthals.and replaced Neanderthals.

APES Homo neanderthalensis Homo sapiens

Homo erectusHomo erectus

transitional speciestransitional species Homo habilis Homo habilis

Australopithecus Australopithecus afarensis afarensis

common ancestor tocommon ancestor to

ape andape and H. sapiens H. sapiens

Mated????Mated????