DESCENT WITH MODIFICATION A Darwinian View of Life AP BIOLOGY Chapter 22 Image from: Biology by Miller and Levine; Prentice Hall Publishing©2006.

DESCENT WITH MODIFICATIONA Darwinian View of LifeAP BIOLOGY Chapter 22

Image from: Biology by Miller and Levine; Prentice Hall Publishing©2006

WHO INFLUENCED DARWIN’S THINKING

Image from: AP BIOLOGY by Campbell and Reece

Figure 22.2

Linnaeus (classification)

Hutton (gradual geologic change)

Lamarck (species can change)

Malthus (population limits)

Cuvier (fossils, extinction)

Lyell (modern geology)

Darwin (evolution, nutural selection)

Mendel (inheritance)

Wallace (evolution, natural selection)

1750

American Revolution French Revolution U.S. Civil War

1800 1850 19001795 Hutton proposes his theory of gradualism.

1798 Malthus publishes “Essay on the Principle of Population.”

1809 Lamarck publishes his theory of evolution.

1830 Lyell publishes Principles of Geology.

1831–1836 Darwin travels around the world on HMS Beagle.

Darwin begins his notebooks on the origin of species.1837Darwin writes his essay on the origin of species.1844

Wallace sends his theory to Darwin.1858

The Origin of Species is published.1859Mendel publishes inheritance papers.1865

Aristotle- (384-322 B.C.)

Species are fixed (unchanging)

BUT recognized similarities

Image from: http://www.ucmp.berkeley.edu/history/aristotle.html

Arranged life forms on a scale of increasing complexity scala natura- “scale of nature”

http://www.kheper.net/topics/greatchainofbeing/index.html

• Founder of TAXONOMY-1735 Science of grouping & naming

• Sought to discover order in the diversity of life “for the greater glory of God”

• Each creature was special- NO evolutionary link

• Devised classification system based

on morphology (form and structure)

(1707-1778)

Image from: http://www.medusozoa.com/images/linnaeus.jpg

Binomial Nomenclature:Naming system that gives organisms a two part scientific name- Genus species Still used today

LINNAEUS’S SYSTEM

Nested hierarchy

Taxon = classification unit to which organisms are assigned

http://content.answers.com/main/content/wp/en-commons/thumb/d/d6/150px-Biological_classification_L_Pengo.svg.png

Ex: Panthera is a taxon at the genus level

Mammalia is a taxon at the class level

Kidspiration by RiedellImage Sources: see end of show

KingdomPhylum

Class Order

Family Genus

Species

Animalia

Chordata

Mammalia

Carnivora

FelidaePanthera

leohttp://www.vetmed.wisc.edu/dms/fapm/personnel/tom_b/2004-lion.jpg

Kids Prefer Cheese Over Fried Green SpinachKings Play Chess On Fat Green StoolsKing Phillip Cried Oh For Goodness Sake!

GENUS = group of closely related species

GENUS = Ursus (Includes many kinds of bears)

SPECIES = unique to each kind of bearhttp://www.macecanada.com/images/bears/kodiak_bear.gifhttp://students.cs.byu.edu/~tole/Virtual%20Zoo/polar-bear.jpghttp://en.wikipedia.org/wiki/Image:Black_bear_large.jpg

Ursusarctos

Ursusmaritimus

Ursusamericanis

Genus and species assignmentsprovide 2 part scientific name

Homo sapiens

Homo sapiens

Image from: http://www.earlylearning.ubc.ca/images/photo_baby.jpg

Modern Taxonomyhas added more Kingdoms

AND more levels (DOMAINS)

Linneaus only used 2 kingdoms (Plants & Animals)

Domains are larger than Kingdoms and are based on the differences in ribosomal RNA

Ideas that shaped Darwin’s thinking:

George Cuvier –Father of Paleontology

http://upload.wikimedia.org/wikipedia/commons/2/28/Georges_Cuvier.jpg

Fossils are remains ofextinct life forms

“CATASTROPHISM” -boundaries represent floods, droughts, etc. that destroyed many species living at that time

ANTI-EVOLUTONIST

Ideas that shaped Darwin’s thinking:

1795 –James Hutton

“GRADUALISM”Profound changes can resultfrom cumulative effect of slow but continuous processes

Proposed that the Earth was shaped by

geological forces occurring over very long

periods of time, and is MILLIONS notTHOUSANDS of years old.

http://www.creationism.org/books/TaylorInMindsMen/TaylorIMMc03.htm

Ideas that shaped Darwin’s thinking:

1833-Charles Lyell Incorporated Hutton’s ideas into “UNIFORMITARIANISM”

Geological processes that shaped Earth are still operating at same rate.

Darwin read his book onthe Beagle voyage

http://www.biologydaily.com/biology/Sir_Charles_Lyell

MODERN GEOLOGY

http://wrgis.wr.usgs.gov/docs/usgsnps/animate/A08.gif

Ideas that shaped Darwin’s thinking:

Thomas Malthus (1798)wrote essay on

population growth

Human suffering (disease, famine, homelessness, and war) are consequences to human population increasing faster than food and other resources

http://www.nndb.com/people/250/000024178/malthus.jpg

Ideas that shaped Darwin’s thinking:

Jean Baptiste Lamarck (1744-1829)

One of first scientists to recognizethat living things changed over time and that all species were descended from other species.

1809- Published his ideas about “Inheritance of Acquired Characteristics”

the year Darwin was born

http://www.educa.rcanaria.es/fundoro/00.corsi.htm

The male fiddler crab uses itsfront claw to attract mates andward off predators.

“USE or DISUSE” = Use it or lose it

Through repeated use, the frontclaw becomes larger.

The fiddler passes on this acquired characteristic to its offspring

INHERITANCE OF ACQUIRED CHARACTERISTICS

What’s wrong with Lamarck’s hypothesis?Lamarck didn’t know

aboutgenes and how traits are

inherited.

Acquired traits are not passed on to offspring

Or are they? . . . New field of EPIGENETICS is exploring this

http://www.geocities.com/arnold_schwarzenegger_pictures/

What’s right with Lamarck’s hypothesis?

Lamarck was first to

develop a scientifichypothesis about evolution and

recognize that organisms areadapted to their environment

http://pegasus.cc.ucf.edu/~he599900/giraffeeating.jpg

Slide by Kim Foglia@ http://www.explorebiology.com/

In 1831, 22-year old Charles Darwin left England as naturalist aboard the HMS Beagle for 5 year voyage around the world.

Mission: Chart the South American coastline

Darwin noticed plants and animals were different from those he knew in Europe

Wrote thousands of pagesof observations and collected vast number ofspecimens

Who Was Charles Darwin?

http://www.solarnavigator.net/history/explorers_history/HMS_Beagle.jpg

Who Was Charles Darwin?

Darwin spent a month observing life on the Galapagos Islands

Each island has different rainfall

and vegetation and its own unique

assortment of plant and animal

species.

Biology by Miller and Levine; Prentice Hall Publishing©2006http://mikebaird.com/ecuador/images/galapagos_off_ecuador_ng_map.jpg

Who Was Charles Darwin?

Although animals on Galapagos resemble species on the South American mainland, many species were found nowhere else in the world = ENDEMIC

http://www.darwinadventure.com/pictures/galapagos_giantortoise.jpghttp://www.destination360.com/south-america/ecuador/galapagos-animals.phphttp://www.photoseek.com/galapago.html

DARWIN’SFINCHES

Darwin collected 14 species of finches and hypothesized that the Galapagos had be colonized by organisms from the mainland that had then diversified on the various

After Darwin returned to England in 1836, he spent years examining specimens he brought back from voyage and filling notebooks with his ideas.

He did not rush to publish his ideas because theydisagreed with the fundamental scientific views of

hisday.

In 1844 he wrote an essay describing his ideas and

asked his wife to publish it if he died.

http://www.elsie.brandeis.edu/images/journals.gif

Who Was Charles Darwin?

In 1858 Alfred Russel Wallace, another

Naturalist working in the West Indies,wrote an essay describing his work

thatsummarized the same ideas Darwin

hadbeen thinking about for 25 years!

http://www.thesecondevolution.com/wallace&darwin.jpg

Suddenly Darwin had incentive to publish

the results of his work!

In 1859On the Origin of Species

by Means of Natural Selectionpresented evidenceand proposed amechanism for evolution that he calledNATURAL SELECTION http://www.loc.gov/exhibits/world/images/s125.jpg

Darwin’s Theory of EvolutionDarwin Presents his Case

Image from: Biology by Miller and Levine; Prentice Hall Publishing©2006

Isn’t evolution “just a theory”?In every day usage “theory” often refers to a hunch or a speculation. When people say, “I have a theory about what happened,” they are often drawing a conclusion based on fragmentary or inconclusive evidence.

The formal scientific definition of “theory” is quite different from the every day meaning.

It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence.http://evolution.berkeley.edu/evosite/evohome.htm

In Science a theory is a well supported, testable explanation of phenomena that have occurred in the natural world.

Example:Cell theoryAtomic theoryGravitational theory

Isn’t evolution just a theory?

http://www.avgoe.de/StarChild/DOCS/STARCH00/questions/apple_falling.gif

http://sixthsense.osfc.ac.uk/chemistry/atomic_structure2/atom.gif

VOCAB ADAPTATION- Any inherited

characteristic that increases an organism’s chance of survival

http://www.3kitty.org/travelrama/Photos/123-21-4x6.jpg

http://www.wildlife-traps.com/skunks.htmlhttp://www.atomtigerzoo.com/photos/images/20060421233733_duckfeet.jpg

OVERPRODUCTION of OFFSPRING

Capacity to over-reproduce seems characteristic of all species.

http://atthecreation.com/DEER/too.many.deer.jpg

http://www.biospheres.com/photogallery2ag/images/ladybugs_jpg.jpg

WHAT IS DARWIN’S THEORY?

WHAT IS DARWIN’S THEORY?

STRUGGLE FOR EXISTANCE means

that members of each species must

compete for food, space, and other resources.

http://www.wasatchcomputers.net/gallery/elk_fight.jpg

WHAT IS DARWIN’S THEORY?

GENETIC VARIATION is found naturally in all populations

http://www3.nationalgeographic.com/animals/images/primary/zebra-herd.jpgImage from www.biologyzone.com

WHAT IS DARWIN’S THEORY?Some organisms in a population are less likely to survive.http://www.cartoonstock.com/newscartoons/cartoonists/rrs/lowres/rrsn69l.jpg

VOCAB Ability of an individual to survive

and reproduce in its specific environment = FITNESS

http://www.cartoonstock.com/newscartoons/cartoonists/cga/lowres/cgan170l.jpg

WHAT IS DARWIN’S THEORY?SURVIVAL OF THE FITTEST =Organisms which are better

adaptedto their environment tend to

producemore offspring than organisms

withoutthose traits.

http://www.poster.net/bedard/bed202.jpg

Over time, NATURAL SELECTIONresults in changes in theinherited characteristics of apopulation.

These changes increase aspecies’ fitness in its environment.

WHAT IS DARWIN’S THEORY?

How Does Evolution Really Work?

•POPULATIONS evolve NOT INDIVIDUALS.

•NATURAL SELECTION only works on heritable traits.

•A trait that is favorable in oneenvironment may be useless or detrimental in another.

IMPORTANT TO REMEMBER !

DESCENT WITH MODIFICATIONsuggests that each species has descended with changesfrom other species over time.

This idea suggests that all living species are related to each other and that all species, living and extinct,share a common ancestor.

WHAT IS DARWIN’S THEORY?

What do oranges, broccoli and

Butterball turkeys have to dowith EVOLUTION?(Answers to come in this slide show!)

http://groups.wfu.edu/ModelUN/images/Cover/Oranges.jpghttp://www.fx.clemson.edu/~ablank/126436919.Broccoli.jpghttp://www.butterball.com/en/images/plan_n_prep/preparing/carving1.jpg

THINK ABOUT IT

EVIDENCE OF EVOLUTION:1. ________________2. ________________3. _______________4. _______________5. _______________6. _________________7. _______________

Fossil recordGeographic DistributionAnatomical homologiesEmbryology

Molecular homologiesCan see Natural selection happen

Artificial selection

ARTIFICIAL SELECTION WORKS

Nature provides the variation through

mutation and sexual reproduction and

humans select those traits that they find

useful

EX: We have selected for and bred cows to produce more milk,turkeys with more breast meat, etc.

http://lazerbrody.typepad.com/photos/uncategorized/turkey.gifhttp://www.pp3moo.com/hm2cow.jpg

BIOLOGY by Campbell and Reece Prentice Hall Publishing©2005

WE’VE DONE IT WITH PLANTS

WE’VE DONE IT WITH ANIMALS

http://www.windows.ucar.edu/earth/geology/images/dogs_sm.jpg

If humans can select for beneficial traits, why can’t nature?

If artificial selection can achieve so much change in relativelyshort time, why can’tmajor changes happenover thousands of generations?

Now you know what broccoli and Butterball turkeys have to do with evolution!

(Answers about oranges to come in this slide show!)

http://groups.wfu.edu/ModelUN/images/Cover/Oranges.jpghttp://www.fx.clemson.edu/~ablank/126436919.Broccoli.jpghttp://www.butterball.com/en/images/plan_n_prep/preparing/carving1.jpg

THINK ABOUT IT

How Do We Know Evolution Happens?

The Fossil Record provides evidence thatorganisms have changedover time.

http://www.bbc.co.uk/schools/gcsebitesize/img/bifossils.gif

If evolution has happened, we should be able to find evidence of evolution in the fossil record AND WE HAVE !

http://en.wikipedia.org/wiki/Image:Tiktaalik_BW.jpg

BBC Tiktaalik video

http://evolution.berkeley.edu/evosite/lines/IAtransitional.shtml

Lots of TRANSITIONAL FOSSILS have been found

Scientific American; Dec 2005; Vol 293; p100-107

TIK-TAALIKIntermediate between fish and early tetrapods

• Fins have basic wrist bones and simple fingers• Earliest fish with a neck

• Discovered by Neil Shubin and Ted Daeschler in 2004

http://evolution.berkeley.edu/evolibrary/images/news/tiktaalik_reconstruction.jpg

GEOGRAPHIC DISTRIBUTION =BIOGEOGRAPHY

If Darwin’s theory is correct you would expect to find closely related yet different species living in a geographic region as they spread into nearby habitats and evolve.

That’s EXACTLY what we do see!

GALAPAGOS FINCHES

The beaks of Galapagos finches have adapted to eating a variety of foods

http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T014608A.gif

GALAPAGOS TORTOISEShttp://www.newtonswindow.com/problem-solving.htm

Image from: BIOLOGY by Miller and Levine; Prentice Hall Publisher©2006

Little vegetationLong necks

Lots of vegetationShort necks

Intermediate vegetationIntermediate necks

Tortoises adapted to different habitats as they spread from the mainland to the different islands.

= DIVERGENT EVOLUTION = ADAPTIVE RADIATION

If Darwin’s theory is correct you would also expect to find different species living in far apart geographic regionsbut similar habitats becoming more alike as they adapt to similar environments.

That’s EXACTLY what we do see!

BOTH LIVE IN FOREST ECOSYSTEMS

Adapted to similar environments, but evolved independently from different ancestors.

SUGAR GLIDER in Australia is a marsupial more closely related to Kangaroos than North American FLYING SQUIRRELS becauseits ancestors were marsupials.

Whales and sharks have a similar body designeven though they are very different organisms (one is a fish; the other, a mammal)because they have independently adapted to living in a similar environment.

http://news.bbc.co.uk/2/shared/spl/hi/guides/456900/456973/html/nn1page1.stm

http://www.flmnh.ufl.edu/fish/gallery/descript/TigerShark/scars.JPG

= CONVERGENT EVOLUTION

HOMOLOGOUS STRUCTURES-Forelimbs of all mammals share same arrangement of bones that can be traced to same embryological origin

BIOLOGY by Campbell and Reece Prentice Hall Publishing©2005

Turtle Alligator Bird Mammal

Ancient lobe-finned fish

Section 15-3

EVOLUTION explains why certain characteristics in related species have an underlying similarity.

amnion /am·ni·on/ (am´ne-on) bag of waters; the extraembryonic membrane of birds, reptiles, and mammals, which lines the chorion and contains the fetus and the amniotic fluid

http://medical-dictionary.thefreedictionary.com/amnionshttp://media-2.web.britannica.com/eb-media/27/117227-050-E1C9ABEE.jpg

VESTIGIAL ORGANSSome homologous structures are vestigial and have no useful function even though they are still present.

Examples: Hipbones and pelvis in whales and boa constrictorsCecum (appendix) in humansSkink legs

http://www.txtwriter.com/backgrounders/Evolution/EVpage12.html

http://www.medicalgeo.com/images/appendix.gif

Most mammals have a pouch between their small and large intestine that contains bacteria to digest plants called a cecum.

In humans the cecum is shrunken and unused.

It is our appendix

EMBRYOLOGY Development of vertebrate embryos follows same path

Image from: http://calspace.ucsd.edu/virtualmuseum/litu/03_3.shtml

Same groups of undifferentiated cells develop in the same order to produce the same tissues and organs of all vertebrates, suggesting that they all evolved from a common ancestor.

Image from: http://io.uwinnipeg.ca/~simmons/16cm05/1116/16anim3.htm

Why grow a tail and then lose it?

http://www.suite101.com/files/topics/6234/files/tail_HumanTail.gif

HUMAN EMBRYO has a tail at 4 weeks which disappears at 8 weeks

Pharyngeal pouchesbecome gills in fish,parts of throat/ears

in humans

http://www.medicalgeo.com/images/appendix.gif

Nonfunctional legs in skinks

Why would an organism possess organs without function?

Why would an organism grow a part and then discard it?If organisms evolved from ancestors in which that

part functioned, the gene code to make the part would still be there even though it doesn’t work.If the organ is not vital to survival, then natural selection would not cause its elimination.

MOLECULAR HOMOLOGIES

• All life forms share same genetic machinery (DNA & RNA)

• Universal genetic code

• Important genes sharehighly conservedsequences

Similarities in protein sequencessuggests similarities in DNA

Image from: Modern Biology by Holt, Rinehart, and Winston

Image from: BIOLOGY AP EDITION by Campbell and Reece; Prentice Hall Publishing©2005

Similarities inDNA and protein sequencessuggestrelatedness

MOLECULAR HOMOLOGIES

Similarities in karyotypes suggest an evolutionary relationship

Human: http://www.nationmaster.com/wikimir/images/upload.wikimedia.org/wikipedia/en/thumb/1/18/300px-Human_karyogram.pngChimpanzee: Middle School Life Science , published by Kendall/Hunt.

Human- 46 chromosomes Chimpanzee- 48 chromosomes

Even differences show relatedness

Human: http://www.nationmaster.com/wikimir/images/upload.wikimedia.org/wikipedia/en/thumb/1/18/300px-Human_karyogram.pngChimpanzee: Middle School Life Science , published by Kendall/Hunt.

Human- 46 chromosomes Chimpanzee- 48 chromosomes

Chimpanzees have 2 smaller chromosome pairs we don’t haveHumans have 1 larger chromosome pair (#2) they don’t have.

PSEUDOGENES are vestigial genes.

EX: Humans have more than 99 different odor receptor genes, but more than 70% of them are nonfunctional.

http://www.animationplayhouse.com/new/dogs2.html

http://unraveling.typepad.com/photos/uncategorized/nose_1.jpg

Slide by Kim Foglia@ http://www.explorebiology.com/

EX: Changes in disease-causing microbes that produce new organisms and new diseases.

_______

___

__________________________

http://www.hipusa.com/eTools/webmd/A-Z_Encyclopedia/tuberculosis.jpg

http://www.hhmi.org/askascientist/images/hiv.gif

Can see Natural selection happen

Bird flu

Antibiotic-resistant tuberculosis

HIV

Why does evolution matter now?

Researchers have developed numerous drugs to combat HIV– But using these medications selects for

viruses resistant to the drugs

Graph from BIOLOGY by Campbell and Reece

PatientNo. 1

Patient No. 2

Patient No. 3

Per

cen

t of

HIV

res

ista

nt

to 3

TC

Weeks

Slide by Kim [email protected]