Darwin’s Theory of EvolutionDarwin Presents his Case

Chapter 15-3

In 1858 another naturalist,_________________, wrote anessay describing his work in _______

thatsummarized the same ideas _____ hadbeen thinking about for 25 years!

Alfred Russel WallaceMalaysia

Darwin

Suddenly Darwin had incentive to publish

the results of his work!

In 1859____________________presented _______ and proposed a________ for evolution that he called__________________

On the Origin of Speciesevidence

mechanism

NATURAL SELECTION

A theory is a ____________, _______, explanation of phenomena that have occurred in the natural world, like the theory of __________________, ________, and _____________.

well-supported testable

gravitational attractioncell theory atomic theory

Isn’t evolution just a theory?

WHAT IS DARWIN’S THEORY?

_________________ is found naturally in all populationsGENETIC VARIATION

WHAT IS DARWIN’S THEORY?______________________means that members of each

species must ________ for food, space, and other __________.

STRUGGLE FOR EXISTANCE

COMPETERESOURCES

WHAT IS DARWIN’S THEORY?Some organisms in a ________are ________ to survive.

populationless likely

WHAT IS DARWIN’S THEORY?_____________________organisms which are better adapted to the environment will ______ and________, passing on their _____.

SURVIVAL OF THE FITTEST

survivereproduce genes

VOCAB Ability of an individual to __________________ in its specific environment = ______fitness

surviveand reproduce

VOCAB Any ___________________ thatincreases an organism’s ______________ = _____________ADAPTATION

inherited characteristicchance of survival

Over time, natural selectionresults in ________ in theinherited characteristics of a __________.

These changes ______ aspecies’ _____ in its environment.

WHAT IS DARWIN’S THEORY?

CHANGES

POPULATION

increasefitness

How Does Evolution Really Work?

____________________________suggests that each species has ___________, with ________,from other species over time.

This idea suggests that all living species are ____________________, and that all species, living and extinct,share a _________________.

WHAT IS DARWIN’S THEORY?DESCENT WITH MODIFICATION

DESCENDED CHANGES

RELATED TO EACH OTHER

COMMON ANCESTOR

EVIDENCE OF EVOLUTION:1.________________2.________________3. _______________4. _______________5. _______________6. _______________7. _______________

Fossil recordGeographic DistributionHomologous structuresEmbryology

DNASee Natural selection happen

Artificial selection

ARTIFICIAL SELECTION WORKSIn artificial selection, ____________provides the _________ through_________ and _________________and ______________ those traits that they find ______.

NATUREvariation

mutation sexual reproductionhumans select

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

Breeds of Dogs

Chihuahua – bred from Techichi of Mexicoby Mayans, had religious significance

Saint Bernard – bred by monks around 1050 A.D. to rescue travelers of mountain passes in the

Swiss Alps between Italy and Switzerland

Irish Wolfhound – bred in Ireland to hunt wolves and elk

Dachshund – bred in Germany as earlyas the 15th century to hunt badgers

____________________________ARTIFICIAL SELECTION WORKS

How Do We Know Evolution Happens?

2. The Fossil Record – ______ are the ________________________found in layers of rock in the Earth.

Fossilsof ancient organisms

remains

How Do We Know Evolution Happens?The layers of rock tell the history of the_____, while the _____ found withinthe rock tell a history of ___.

The fossils are thought to be the ________ as the rock theyare found in.

Earth fossilslife

same age

Go to Section:

Sea level

Sedimentary rocks form in horizontal layers.

When part of Earth’s crust is compressed, a bend in a rock forms, tilting the rock layers.

As the surface erodes due to water, wind, waves, or glaciers, the older rock surface is exposed.

Movement of Earth’s CrustSection 15-2

Fish die inthe oceanand arecovered insediment.Over timeand underincreasingpressure,the remainsbecomesfossilized

Earthquakes and volcanoescause uplifting of the layers of the

Earth, taking the fossils along

Fossils ofmarinefish foundon themountain-sides ofsouthwestWyoming,which atone timewas covered by aninland sea

TRANSITIONAL FOSSILS HAVE BEEN FOUND

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

TIK-TAALIKTIK-TAALIKIntermediate between fish and early tetrapods

Fins have basic wrist bones and simple fingersEarliest fish with a neck

Discovered by Neil Shubin and Ted Daeschler in 2004

Fossil record shows change

over time

SD dinosaur fossils

If Darwin’s theory is correct you would expect to find ____________ yet _______________ living in a _________ region as they spread into nearby habitats and evolve.

different speciesclosely related

geographic

That’s EXACTLY what we do see!

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

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

GALAPAGOS FINCHES

The _____ of Galapagos finches have ______ to eating a _____ of _____.

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

beaksadapted variety foods

If Darwin’s theory is correct you would also expect to find _______________ living in ________ geographic regionsbut similar habitats becoming ________ as they adapt to ______________.

far apartdifferent species

more alike

That’s EXACTLY what we do see!

similar ecosystems

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

= CONVERGENT EVOLUTION

similardifferent

independently adaptedsimilar

Whales are closely related to wolves, but don’t look or act much like them = divergent evolution

Whales are distantly related to sharks, but look and act morelike them =convergent evolution

Conclusion:The pressure ofthe environmentdrives evolution

Go to Section:

Figure 15–14 Geographic Distribution of Living Species

Section 15-3

Beaver

NORTH AMERICA

Muskrat

CapybaraSOUTH AMERICA

Coypu

Beaver

Muskrat

Beaver andMuskrat

Coypu

Capybara

Coypu andCapybara

Beaver and capybaraare _____________________ living in very ________ environments,while beaver and musk-rat are ______________________ living in a______ environment.Differences betweenbeaver and capybarashow _________ evolution, while similaritiesbetween beaver andmuskrat show __________ evolution.

Differences between _____________ muskratand coypushow _________evolution, whilesimilarities between ______________ capybaraand coypu show___________evolution.

closely-relatedspeciesdifferent

distantly-relatedspeciessimilar

divergent

convergent

closely-related

divergent

distantly-related

convergent

4. _____________________HOMOLOGOUS Structures

4. Homologous Body Structures – Structures, like the limbs of vertebrates, look very _______, but are made from the __________, because they are made fromthe same clump of _____________ cells in the _______.

same bones

embryoundifferentiated

different

Go to Section:

Turtle Alligator Bird Mammal

Ancient lobe-finned fish

Figure 15–15 Homologous Body Structures

Section 15-3

4. Homologous Body Structures – Some _______________________are _______ and have no usefulfunction even though they are still present, like ________in whales and boa constrictors, or a ____ and ________________in humans.

homologous body structuresvestigial

hipbonestail

cecum (appendix)

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

In humans the cecum is shrunken and unused.

It is our _________appendix

cecum

Why grow a tail and then lose it?

HUMAN EMBRYO_________________

__________________________________Tail disappears at

has a tail at 4 weeks

about 8 weekstail

Skinks are a type of lizard. In some species, legs have become so small they _______

______ in walking. Why would an organism possess organs ___________________?One explanation:The ________ is present to make the organ, but_________________ through ______________.If the organ is not vital to survival, then natural selection would not cause its elimination.

no longerfunction

gene codechange over timefunction has been lost

little or no functionwith

5. _____________________________ of many animals with back-bones are very similar.

Similarities in EmbryologyEmbryos

It is clear that the same groups of _____________ cells develop in the same order to produce the same tissues and organs of all vertebrates, suggesting that they all _______ from a _______________.

undifferentiated

evolvedcommon ancestor

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

6. _______________

Similarities in ____ and ________ sequencessuggestrelatedness

Similarities in DNA

PROTEINDNA

Similar _________ suggest an ___________________.

Human- 46 chromosomes Chimpanzee- 48 chromosomes

karyotypesevolutionary relationship

1. ________________________If you take the two smaller chromosomes apes have that we don’t, and place them end to end, the ______ _______________ to the #2 human chromosome __________________.

BANDING PATTERN MATCHES

bandingpattern is identical

wehave that they don’t

2. ____________________Chromosomes have special sequences called _______ at their ends to protect the strands during replication.

TELOMERES IN MIDDLE

telomeres

2. TELOMERES IN MIDDLE Telomere sequences are found __________ and _____________________ of human chromosome #2 suggesting it was made by _____ two other chromosomes together.

→

→

→ALSO IN THE MIDDLE

at the ends

fusing

WHY DOES EVOLUTION MATTER NOW?

There is a natural variation in populations of peppered moths.

________________

___________________

7.____________________________EX: Peppered Moths

Can see Natural selection happen

Typica form - lighter

Carbonaria form - darker

Typica

Carbonaria

The ___________ form was the predominant form in England _____________________________.

Around the middle of the 19th century the ______ form began to appear. It was first reported in 1848. By 1895 98% of the moths in Manchester were the ____ variety.

In recent years, the burning of cleaner fuels and Clean Air regulations has reduced the pollution there and the ______ colored moths have increased in numbers.

light coloredprior to the Industrial Revolution

darker

dark

lighter

7.____________________________EX: Changes in disease-causing microbes that produce new organisms and __________.

_______

___

__________________________

Can see Natural selection happen

Bird flu

Antibiotic-resistant tuberculosis

HIV

new diseases

PBS EVOLUTION VIDEO CLIPSIsn’t Evolution Just a Theory? QuickTime

Who was Charles Darwin? QuickTime

How Do we Know Evolution Happens? QuickTime

How Does Evolution Really Work? QuickTime |

Why Does Evolution Matter Now? QuickTime

Why is Evolution Controversial Anyway? QuickTime