Darwin’s Theory of EvolutionThe Puzzle of Life’s Diversity

Chapter 15-1

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Section Outline

15–1 The Puzzle of Life’s DiversityA. Voyage of the BeagleB. Darwin’s Observations

1.Patterns of Diversity2.Living Organisms and Fossils3.The Galápagos Islands

C. The Journey Home

Section 15-1

DefinitionsEVOLUTION:

THEORY:

FOSSIL:

change over time; the process by which modern organisms have descended from ancient organisms

a well-supported testable explanation of phenomena that have occurred in the natural world

the preserved remains of ancient organisms

evolution

fossiltheory

The _______ that Darwin found caused him to ask questions that led to his proposal of the theory of

_________. _______ provide

evidence to support the theory of

_________.

________ is a______; a testable explanation of naturally-occurring phenomena

The _____ record provides for some of the evidence that supports the ______ of evolution

Evolutiontheory

fossils

evolutionFossils

evolution

fossil

theory

The person who contributed themost to our understanding of evolution was ______________________

In 1831, at age 22, he joined the crew of

the _______________ as a naturalist fora ________ voyage around the world.

Charles Darwin

H.M.S. Beagle

http://harrier.users.netlink.co.uk/Darwin_sm.jpg

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

5 year

Charles Darwin

• English naturalist• (1831) Set sail on the

Beagle for a voyage around the world

• During his travels, Darwin made many observations & collected a great deal of evidence, leading him to propose the theory of evolution

Cont. Charles Darwin

• Collected fossils preserved remains of ancient organisms

• Noticed that many plants & animals were very suited to their environments.

• Spent much time in Galapagos Islands in Pacific Ocean near South America

DARWIN WONDERED?

Why do Argentina and Australia have ______________ even though they have ______________________?

Why are there no ______ in Australia andno ________ in England?

Why have so many species disappeared?

How are these ______ species _______ to living species?

http://www.rc.umd.edu/praxis/mitchell/images/dinosaur1.gif

different

animals similar grassland

ecosystems

rabbitskangaroos

extinct

related

The Galάpagos Islands are close together but have very different _______.

Some were hot and dry, with

little vegetation.Others had more rainfall and were

rich in vegetation

Each island hadits own _____ _________ of plant and animal species.

Biology by Miller and Levine; Prentice Hall Publishing©2006

climates

assortmentunique

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Pinta IslandIntermediate shell

Pinta

Isabela IslandDome-shaped shell

Hood IslandSaddle-backed shellHoodFloreana

Santa Fe

Santa Cruz

James

Marchena

Fernandina

Isabela

Tower

Giant Tortoises of the Galápagos Islands

Section 15-1

On the desert-like Hood Island,tortoises had long necks…

…while on the lush rainforest of Isabela Island,tortoises had short necks…

and on Pinta Island, tortoise neckswere somewhere in between

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Tortoises from the Galapagos Islands

After his voyage, Darwin spent a great deal of time thinking about his findings.

He began to wonder if animals living ondifferent islands had once been membersof the ____________ that haddeveloped _________ characteristicsafter becoming _______ from oneanother in different habitats.

same speciesdifferent

isolated

Biology by Miller and Levine; Prentice Hall Publishing©2006

Darwin’s Theory of EvolutionIdeas that Shaped Darwin’s

ThinkingChapter 15-2

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Section Outline

15–2 Ideas That Shaped Darwin’s ThinkingA. An Ancient, Changing Earth

1.Hutton and Geological Change2.Lyell’s Principles of Geology

B. Lamarck’s Evolution Hypotheses

1.Tendency Toward Perfection2.Use and Disuse3. Inheritance of Acquired Traits4.Evaluating Lamarck’s Hypotheses

C. Population Growth

Section 15-2

Ideas that shaped Darwin’s thinking:

In 1785 ______________proposes that the ______________ by_________________occurring over__________ periods of time, and is_______________ old. Rocks can be

pushed from the ocean floor to form __________.

very long

James Hutton

Earth was shapedgeological forces

millions of years

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

mountains

Ideas that shaped Darwin’s thinking:

In 1833 ___________ explains that the geological processes still ___________ have shaped Earth’s features over ________________

Charles Lyell

occurring now

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

long periods of time

Ideas that shaped Darwin’s thinking:

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

Theory of Pangaea

…and continentaldrift

Ideas that shaped Darwin’s thinking:

_____________________

He observed that babies were being bornfaster than people were dying. Hereasoned that if the human populationcontinued to grow, sooner or later therewould be _______________________

Thomas Malthus (1798)

insufficient space & food

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

Ideas that shaped Darwin’s thinking:

___________________________was one of first scientists to recognize living things_______________ and thatall species were ________ fromother species.

Lamarck published his hypothesis of________________________ the year Darwin was born.

changed over time

Jean-Baptiste Lamarck (1809)

descended

Inheritance of Acquired traits

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

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

Through repeated use, the frontclaw becomes larger.

The fiddler passes on this acquired characteristic to its offspring

Lamarck’s Hypothesis:

True or false?

What’s wrong with Lamarck’s hypothesis?Lamarck didn’t know aboutgenes and how traits are

_______.

If you lifted weights yourwhole young adult life, andthen you had children, wouldyour kids be more muscular?

inherited

NO! Acquired traits may help an organism, but they won’t be passed on to offspring.

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

What’s right with Lamarck’s hypothesis?

Lamarck was first to develop a scientifichypothesis about _______and recognize that organisms are________________________

evolution

adapted to their environments

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

a. The earth is really old, and slowly changesb. Living things pass changes on to their offspring, leading to species changesc. Sooner or later growing populations run out of resourcesd. Living things change slowly over time because of competition for resources,

and pass those changes on to their offspring

Hutton

Lyell

Malthus

Lamarck

Match the letter of the idea withthe man or men who proposed it:

a. The earth is really old, and slowly changesb. Living things pass changes on to their offspring, leading to species changesc. Sooner or later growing populations run out of resourcesd. Living things change slowly over time because of competition for resources,

and pass those changes on to their offspring

Hutton

Lyell

Malthus

Lamarck

a.

c.

b.

d.

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Concept Map

Section 15-3

includes

Evidence of Evolution

Physical remains of organisms

Common ancestral species

Similar genes Similar genes

which is composed of which indicates which implies which implies

The fossil recordGeographic

distribution of living species

Homologous body structures

Similaritiesin early

development

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Section 15.3Darwin Presents His Case

The beaks of four species of Galapagos finches, from Darwin's Journal of Researches, 1839.

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Darwin’s Theory

Darwin didn’t publish his ideas for 20 years!

Darwin published On the Origins of Species in 1859.

It provides evidence that evolution has occurred by NATURAL SELECTION.

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Basis of Darwin’s Theory

His theory was based on artificial selection:

Animal breeders breed animals only with desired traits. Those desired traits are passed down to the next generation.

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Darwin’s Theory: Natural Selection

In nature, this is called NATURAL SELECTION. Individuals best suited to their environment survive & reproduce most successfully.

AKA “Survival Of The Fittest” (sometimes called “Reproduction of the Fittest”)

Struggle For Existence: is there an unlimited food supply?

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Darwin’s Theory continued

Fitness ability to survive & reproduce in a specific environment

Results from adaptations, or inherited characteristics that increase the organism’s chances of survival.

Only the fittest organisms pass on their traits to offspring

Thus, the species changes over time.

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How can you get an adaptation?

Can you “get” one at all?

Adaptations are inherited characteristics… you are born with them!

Adaptations are mutations that are beneficial in a particular environment!

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Evidence of Evolution

A) Homologous structures structures that have different mature forms but develop from the same embryonic tissues

B) Similarities in early development, or embryology

C) Fossil record

D) Geographical distribution of living organisms (where the organisms are)

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Homologous Structures

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Similarities in Embryology

•In their early stages of development

•Embryos of different species develop almost identically

•This provides evidence that they share a common ancestry