Do you think these birds are related? Why or Why Not?

A

B

C

D

E

What do you think each bird eats? Why do you think that?

Change Over TimeChange Over Time

Organisms adapt to suit their Organisms adapt to suit their environment – they evolveenvironment – they evolve

Who is Darwin?Who is Darwin?

Charles Charles DarwinDarwin is is considered the father of considered the father of modern evolutionary modern evolutionary theorytheory

Darwin’s 5 year voyage as Darwin’s 5 year voyage as the naturalist on the the naturalist on the HMS HMS BeagleBeagle helped him helped him develop the theory of how develop the theory of how change over time occurschange over time occurs

Section 15-1

Figure 15–1 Darwin’s Voyage

They They exploredexplored South America and the South America and the South Pacific, including the now famous South Pacific, including the now famous GalapagosGalapagos Islands off the coast of South Islands off the coast of South AmericaAmerica

They collected samples of They collected samples of fossilsfossils and and livelive specimens for studyspecimens for study

The islands had animals that were The islands had animals that were uniqueunique, but they also had species that , but they also had species that were were similarsimilar to those on the to those on the mainlandmainland– Ex: marine iguanas and tortisesEx: marine iguanas and tortises

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

DarwinDarwin PresentsPresents HisHis CaseCase

Through his observations abroad, he Through his observations abroad, he concluded that concluded that naturalnatural variationsvariations or or differencesdifferences occur among individuals occur among individuals of a populationof a population– EX: Galapagos FinchesEX: Galapagos Finches

Natural SelectionNatural Selection

What is Natural Selection: What is Natural Selection: – Organisms with more Organisms with more favorablefavorable traits or traits or

variations tend to variations tend to survivesurvive and and reproducereproduce; organisms with less ; organisms with less favorable traits are favorable traits are lessless likely to survive likely to survive

2 Main Points of Natural 2 Main Points of Natural SelectionSelection

1.1. Struggle for existenceStruggle for existence: competition : competition for for territoryterritory, , foodfood, , waterwater, and , and matesmates

2.2. Survival of the fittestSurvival of the fittest: some : some organisms are better suited to organisms are better suited to survive in an survive in an environmentenvironment as a as a result of result of adaptationsadaptations

- Examples of Adaptations- Examples of Adaptations

MimicryMimicry: : copyingcopying the appearance of the appearance of other speciesother species

CamouflageCamouflage: : blendingblending into the into the environmentenvironment

Adaptations can take Adaptations can take millionsmillions to to hundreds of yearshundreds of years

Bacteria show adaptations in Bacteria show adaptations in 5050 or or less yearsless years

MimicryMimicry

CamouflageCamouflage

Before the Industrial Revolution, the white peppered moths were camouflaged better than the black peppered moth in England.

However, the pollution However, the pollution caused by the caused by the

industrial revolution industrial revolution caused a lot of the caused a lot of the

trees around England trees around England to become a black to become a black

color. The number of color. The number of white moths white moths

decreased, where the decreased, where the number of black number of black

moths increased, this moths increased, this is population change is population change

over timeover time

Evidence for Change Over Evidence for Change Over TimeTime

1.1. FossilsFossils: by using fossils, scientists can : by using fossils, scientists can show the show the sequencesequence of evolution in an of evolution in an organismorganism

2.2. GeographyGeography: organisms that are : organisms that are similarsimilar but live in different parts of the but live in different parts of the worldworld

– Earth has changed over the last 4.6 billion Earth has changed over the last 4.6 billion years: Pangaea (the super continent)years: Pangaea (the super continent)

Beaver

NORTH AMERICA

Muskrat

Capybara SOUTH AMERICA

Coypu

Figure 15–14 Geographic Distributionof Living Species

Section 15-3

Beaver

Muskrat

Beaver andMuskrat

Coypu

Capybara

Coypu andCapybara

Evidence for EvolutionEvidence for Evolution

3.3. Homologous Homologous StructuresStructures: : structures that structures that are are similarsimilar and and seen in different seen in different speciesspecies

• Ex: forelimbs of Ex: forelimbs of humans/batshumans/bats

Evidence for EvolutionEvidence for Evolution

4.4. Vestigial StructuresVestigial Structures: a body : a body structure that appears to structure that appears to nono longerlonger have a functionhave a function

• Ex: appendix in humans, hipbones in Ex: appendix in humans, hipbones in snakessnakes

Vestigial StructuresVestigial Structures

Evidence for EvolutionEvidence for Evolution

5.5. EmbryologyEmbryology: by studying unborn : by studying unborn organisms, we can see structures in organisms, we can see structures in common during common during developmentdevelopment in in different organismsdifferent organisms

EmbryologyEmbryology

EmbryologyEmbryology

EmbryologyEmbryology

6.6. Genetic RelationshipsGenetic Relationships: : DNADNA comparisons help establish comparisons help establish evolutionary relationships between evolutionary relationships between differentdifferent species species

Extra Tidbit of InfoExtra Tidbit of Info

Sometimes organisms with close Sometimes organisms with close relationships (like symbiosis) evolve relationships (like symbiosis) evolve together in response to each together in response to each other’s changesother’s changes

• Madagascar orchid and hawk mothMadagascar orchid and hawk moth

To reach the nectar of this orchid requires a 30 centimeter (eleven inch) proboscis (tongue) to penetrate the long nectar spur (white arrow).