get out your notebook write down: –what is one career that collects evidence for evolution?...

Get out your notebookGet out your notebook

Write down: Write down: – What is one career that collects evidence for What is one career that collects evidence for

evolution?evolution?– What is evolution?What is evolution?

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History of History of Evolutionary Evolutionary

ThoughtThought

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Early Ideas On EarthEarly Ideas On Earth’’s s OrganismsOrganisms

AristotleAristotle believed species believed species were were fixed fixed creationscreations arranged by their arranged by their complexitycomplexity

Idea Idea lasted 2000lasted 2000 yearsyears

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Early Ideas On EarthEarly Ideas On Earth’’s s OrganismsOrganisms

LinnaeusLinnaeus – 1 – 1stst to to group similar group similar organisms and organisms and assign them assign them LatinLatin names names

Two word name Two word name (Genus species)(Genus species)

Known as Known as Binomial Binomial nomenclaturenomenclature

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LamarckLamarck’’s Theory of s Theory of EvolutionEvolution

Jean-Baptiste LamarckJean-Baptiste Lamarck, , 18091809One Of First Scientists One Of First Scientists To Understand That To Understand That Change Occurs Over Change Occurs Over TimeTimeStated that Changes Are Stated that Changes Are Adaptations To Adaptations To Environment Environment acquired in acquired in an organisman organism’’s lifetimes lifetimeSaid acquired changes Said acquired changes were passed to offspringwere passed to offspring

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Idea called Idea called Law of Use Law of Use and Disuseand Disuse

If a body part If a body part were used, it were used, it got strongergot stronger

If body part If body part NOT used, it NOT used, it deteriorateddeteriorated

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Inheritance of Acquired Inheritance of Acquired CharacteristicsCharacteristics

Proposed That By Selective Use Or Proposed That By Selective Use Or Disuse Of Organs, Organisms Acquired Disuse Of Organs, Organisms Acquired Or Lost Certain Traits During Their Or Lost Certain Traits During Their LifetimeLifetime

These These Traits Could Then Be Passed On Traits Could Then Be Passed On To Their OffspringTo Their Offspring

Over Time This Led To Over Time This Led To New SpeciesNew Species

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Use & Disuse - Use & Disuse - Organisms Could Organisms Could Change The Size Or Change The Size Or Shape Of Organs By Shape Of Organs By Using Them Or Not Using Them Or Not Using ThemUsing ThemBlacksmiths & Their Blacksmiths & Their SonsSons (muscular arms) (muscular arms)GiraffeGiraffe’’s Necks Longers Necks Longer from stretching)from stretching)

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Inheritance Of Acquired TraitsInheritance Of Acquired Traits– Traits Acquired During Ones Traits Acquired During Ones

Lifetime Would Be Passed To Lifetime Would Be Passed To OffspringOffspring

Clipped ears of dogs could be passed to offspring!

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Tendency Toward PerfectionTendency Toward Perfection

Organisms Are Continually Organisms Are Continually Changing and Acquiring Features Changing and Acquiring Features That Help Them Live More That Help Them Live More Successfully In Their Successfully In Their EnvironmentEnvironment

Example:Example: Bird Ancestors Desired Bird Ancestors Desired To Fly So They Tried Until Wings To Fly So They Tried Until Wings DevelopedDeveloped

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LamarckLamarck’’s Mistakess Mistakes

Lamarck Did NOT Know how Lamarck Did NOT Know how traits were traits were inherited (Traits inherited (Traits are passed through genes)are passed through genes)Genes Are NOT Changed By Genes Are NOT Changed By Activities In LifeActivities In LifeChange Through Change Through Mutation Mutation Occurs Before An Organism Is Occurs Before An Organism Is BornBorn

What we know now:What we know now:

Phenotype: Phenotype: The physical characteristics that The physical characteristics that are expressed based on a species’ genes (what are expressed based on a species’ genes (what we see)we see)

Genotype: Genotype: The DNA/genetic code that The DNA/genetic code that determines how an organism looks (we cannot determines how an organism looks (we cannot see it). Passed from generation to generation.see it). Passed from generation to generation.

Phenotype can change Phenotype can change during life, but during life, but this will never change genotype, so this will never change genotype, so these these traits are not inheritable. traits are not inheritable.

Evolution and Natural Evolution and Natural SelectionSelection

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Charles Darwin Charles Darwin the Naturalistthe Naturalist

copyright cmassengalecopyright cmassengale

I. Charles DarwinI. Charles Darwin

- Charles Darwin is the father Charles Darwin is the father of evolutionary theory.of evolutionary theory.

- What question is he trying What question is he trying to solve?to solve?- Why do populations change Why do populations change

over time?over time?

It took Darwin years to develop his theory of It took Darwin years to develop his theory of evolution; eventually published ideas in book evolution; eventually published ideas in book entitled entitled On the Origin of SpeciesOn the Origin of Species

He began in 1831 at age 22 when he took a He began in 1831 at age 22 when he took a job as a naturalist on the English ship HMS job as a naturalist on the English ship HMS BeagleBeagle, which sailed around the world on a , which sailed around the world on a five-year scientific journey.five-year scientific journey.

Darwin on HMS BeagleDarwin on HMS Beagle

A map of DarwinA map of Darwin’’s voyages voyage

1919

The Galapagos IslandsThe Galapagos Islands

Finches on the islands Finches on the islands resembled a resembled a mainland finchmainland finchMore types of finches appeared on More types of finches appeared on the islandsthe islands where the available food where the available food was different (seeds, nuts, berries, was different (seeds, nuts, berries, insects…)insects…)Finches had Finches had different types of beaksdifferent types of beaks adapted to their adapted to their type of food type of food gatheringgathering

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DarwinDarwin’’s Observationss Observations

Left unchecked, with unlimited resources, the number of organisms of each species will increase exponentially, generation to generationIn nature, populations tend to remain stable in sizeEnvironmental resources are limited

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DarwinDarwin’’s Conclusions Conclusion• Production of more

individuals than can be supported by the environment leads to a struggle for existence among individuals

• Only a fraction of offspring survive each generation

• Survival of the Fittest

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DarwinDarwin’’s Observationss Observations

• Individuals of a population vary extensively in their characteristics with no two individuals being exactly alike.

• Much of this variation between individuals is inheritable.

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DarwinDarwin’’s Conclusions Conclusion

• Individuals who inherit characteristics most fit for their environment are likely to leave more offspring than less fit individuals

• Called Natural Selection

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•The The unequal ability of individuals unequal ability of individuals to survive and reproduceto survive and reproduce leads to leads to a gradual change in a population, a gradual change in a population, with favorable characteristics with favorable characteristics accumulating over generations accumulating over generations (natural selection)(natural selection)•New species evolveNew species evolve

DarwinDarwin’’s s

Theory Theory of of

EvolutioEvolutionn

EvolutionEvolution

- Evolution is when a POPULATION of Evolution is when a POPULATION of organisms changes over timeorganisms changes over time

- Darwin proposed the idea that evolution Darwin proposed the idea that evolution happens through natural selection.happens through natural selection.

- Developed from his idea of Developed from his idea of artificial artificial selectionselection = nature provides variation and = nature provides variation and HUMANSHUMANS select variations they find useful select variations they find useful

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Natural Variation and Natural Variation and Artificial SelectionArtificial Selection

Key Concept:Key Concept:

In In Artificial SelectionArtificial Selection,, Nature Nature Provided The Variation Provided The Variation Among Different Among Different Organisms, And Humans Organisms, And Humans Selected Those Variations Selected Those Variations That They Found UsefulThat They Found Useful

II. Natural SelectionII. Natural Selection

- Natural selection is the way evolution Natural selection is the way evolution happens. That is, natural selection is happens. That is, natural selection is how organisms change over time.how organisms change over time.

- Natural selection is when nature selectsNatural selection is when nature selectsa.a. organisms with organisms with goodgood genesgenes to live and pass to live and pass

on their genes and…on their genes and…

b.b. organisms with bad genes to die outorganisms with bad genes to die out


- In any population, there In any population, there are differences between are differences between species.species.

- For example: These fish For example: These fish

are different sizes, are different sizes, shapes and speeds.shapes and speeds.

- What causes these What causes these differences?differences?- Mutations (alterations in Mutations (alterations in

DNA sequences)DNA sequences)


- Organisms with Organisms with helpfulhelpful traits, such as traits, such as being fast, survive being fast, survive better in their better in their environment, environment, compared to being compared to being slower.slower.


- Over timeOver time, only the , only the organisms with the organisms with the good genesgood genes (in this (in this example, fast fish) will example, fast fish) will survive and the new survive and the new population of fish will population of fish will look very different look very different from their ancestors:from their ancestors:

Ancestors (Great-Grandparents)

New population of fish

- Fitness: the physical traits and behaviors that enable organisms to survive and reproduce in their environment

- Common Descent: the idea that all species have common ancestors

II.II. Natural SelectionNatural SelectionSometimes called Sometimes called ““Survival of the Survival of the

FittestFittest””

Darwin’s Theory of Natural Selection

1.Individual Organisms In Nature Differ From One Another. Some Of This Variation Is Inherited2.Organisms In Nature Produce More Offspring Than Can Survive, And Many Of These Offspring Do No Reproduce3.Because More Organisms Are Produced Than Can Survive, Members Of Each Species Must Compete For Limited Resources4.Because Each Organism Is Unique, Each Has Different Advantages & Disadvantages In The Struggle For Existence5.Individuals Best Suited To Their Environment Survive & Reproduce Successfully – Passing Their Traits To Their Offspring.6.Species Change Over Time. Over Long Periods, Natural Selection Causes Changes That May Eventually Lead To New Species7.Species Alive Today Have Descended With Modifications From Species That Lived In The Past8.All Organisms On Earth Are United Into A Single Tree Of Life By Common Descent

You are Darwin. You are Darwin. ExplainExplain why and why and how this change could happen.how this change could happen.

Finch Beak SizeFinch Beak Size

These two finches These two finches came from the same came from the same ancestor.ancestor.

According to Darwin, According to Darwin, how did they come to how did they come to look different?look different?

What would Lamarck What would Lamarck had said?had said?

Exit TicketExit TicketWhat is the process that natural selection drives called? (Points….1…0…)What is the process that natural selection drives called? (Points….1…0…)

a. Speciationa. Speciation

b. Natural Selectionb. Natural Selection

c. Evolutionc. Evolution

d. Degradationd. Degradation

Which one of these is an example of natural selection? (Points…1…0…)Which one of these is an example of natural selection? (Points…1…0…)

a. A snake loses its skin once a month to remove parasites.a. A snake loses its skin once a month to remove parasites.

b. A population of fish with an avian predator gradually changes over time from grey-blue to a b. A population of fish with an avian predator gradually changes over time from grey-blue to a green color as the color of the water in their pond becomes greener due to green algae green color as the color of the water in their pond becomes greener due to green algae growth.growth.

c. A single giraffe stretches his neck every day until it grows longer so that he can eat taller c. A single giraffe stretches his neck every day until it grows longer so that he can eat taller vegetation.vegetation.

d. A dog barks to warn its owner when someone comes to the door. d. A dog barks to warn its owner when someone comes to the door.

Predict what would happen in the following scenario: (Points…5…4…3…2…1…)Predict what would happen in the following scenario: (Points…5…4…3…2…1…)

There is a large population of wolves. They all have different length fur in their coats. Some have very There is a large population of wolves. They all have different length fur in their coats. Some have very long, thick fur. Others have very long, thin fur. And still others have short, thin fur. There are no long, thick fur. Others have very long, thin fur. And still others have short, thin fur. There are no wolves with short, thick fur. Predict what would happen to the wolf population if there was a wolves with short, thick fur. Predict what would happen to the wolf population if there was a climate change that caused the temperatures to drop 20 degrees throughout the year. (If you climate change that caused the temperatures to drop 20 degrees throughout the year. (If you need more room please use the back of this page).need more room please use the back of this page).

get out your notebook write down: –what is one career that collects evidence for evolution?...

Documents

traits traits

deteriorated slide

binomial nomenclature

organisms lifetime

species genes

inherited traits

similar organisms

perfection organisms