Evolution HistoryEvolution History

Evolution Part I:Evolution Part I: Who was Who was Darwin?Darwin?

The story begins hereThe story begins here

EuropEuropee

United United KingdoKingdo

mm

In the country of EnglandIn the country of EnglandIn Shropshire countyIn Shropshire countyIn the town of In the town of ShrewsburyShrewsbury

lived this famous naturalistlived this famous naturalistwhose name was Charles Darwinwhose name was Charles Darwin

Age Age 6565

Charles DarwinCharles Darwin

1809 - 18821809 - 1882

This was his home and his gardenThis was his home and his garden

Darwin would spend much time walking in his Darwin would spend much time walking in his garden thinking about his discoveries and ideas.garden thinking about his discoveries and ideas.

This was his glasshouse and his This was his glasshouse and his studystudy

Darwin spent a lot of time in his glasshouse and Darwin spent a lot of time in his glasshouse and study examining various plants and animals and study examining various plants and animals and developing his theory of natural selection.developing his theory of natural selection.

Evolution HistoryEvolution History

Evolution Part Evolution Part II:II:

Darwin finds Darwin finds his niche.his niche.

Darwin started Darwin started medical studies at medical studies at

Edinburgh’s Edinburgh’s famous medical famous medical

school,school,

but switched over but switched over to a course in to a course in

scientific inquiry, scientific inquiry, becoming a becoming a

naturalist instead.naturalist instead.

As a young As a young man, man,

A naturalist is a A naturalist is a person who studies person who studies past and present plant past and present plant and animal life.and animal life.

Darwin’s Darwin’s OccupationOccupation

Naturalists spend a lot Naturalists spend a lot of time collecting and of time collecting and classifying plants and classifying plants and animals.animals.

Carolus Carolus LinnaeusLinnaeus

1707 - 17781707 - 1778

Like most naturalists, Darwin Like most naturalists, Darwin used Linnaeus’ Hierarchy of used Linnaeus’ Hierarchy of

Taxononmic Levels to classify Taxononmic Levels to classify organisms.organisms.

KingdomKingdom

PhylumPhylum

ClassClass

OrdeOrderrFamilFamilyyGenuGenussSpecieSpeciess

Canis Canis lupuslupus

AnimaAnimall

CarnivoraCarnivora

ChordataChordata

MammaliaMammalia

CanidaCanidaeeCaniCani

ss

DomaiDomainn

EukaryEukaryaa

Darwin on ClassifyingDarwin on Classifying

Darwin spent eight years in his study looking through Darwin spent eight years in his study looking through a microscope at barnacles he collected from around a microscope at barnacles he collected from around the worldthe world

What’s a barnacle you What’s a barnacle you ask?ask?

Barnacle StructureBarnacle StructureBarnacles live in water Barnacles live in water and colonize rocks, and colonize rocks, docks, and ships’ hulls, docks, and ships’ hulls, which cause the ships which cause the ships to slow down. to slow down.

The classic barnacle is The classic barnacle is an animal with the an animal with the body plan of a volcano body plan of a volcano — a cone with a crater — a cone with a crater at the top.at the top.

Barnacle LifeBarnacle LifeEvery day when the tide Every day when the tide rolls in, each barnacle pokes rolls in, each barnacle pokes out of its crater a long foot out of its crater a long foot like a feather duster and like a feather duster and gathers food.gathers food.When the tide goes out, When the tide goes out, each barnacle pulls in the each barnacle pulls in the feather duster and clamps feather duster and clamps its crater closed with an its crater closed with an operculum—a shelly lid.operculum—a shelly lid.

““Barnacle Barnacle Bill”Bill”

Darwin found so much Darwin found so much variation in barnacle variation in barnacle structure and function that structure and function that he had great difficulty he had great difficulty classifying them. classifying them.

Before Darwin’s time, most Before Darwin’s time, most people believed thatpeople believed that

all life suddenly all life suddenly appeared in its appeared in its present form, (Special present form, (Special Creation);Creation);life was immutable life was immutable (unchanging);(unchanging);

the Earth was less than the Earth was less than 10,000 years old.10,000 years old.

Georges Georges BuffonBuffon

1707 - 17881707 - 1788 The earth appears to The earth appears to be formed by slow be formed by slow action on natural action on natural causes.causes.

Some individuals however thought the Some individuals however thought the earth was much olderearth was much older

James HuttonJames Hutton1726 - 17971726 - 1797

Some proposed that evolution occurred, but Some proposed that evolution occurred, but lacked convincing evidence for the driving lacked convincing evidence for the driving

mechanism.mechanism.

Jean Babtiste LamarckJean Babtiste Lamarck1744 - 18291744 - 1829

Inheritance of Acquired Inheritance of Acquired CharactersCharactersThe behavior of the individual The behavior of the individual

determines the character that determines the character that its offspring inherit.its offspring inherit.

For example, passing on For example, passing on longer necks by longer necks by stretching for food stretching for food seems reasonable. seems reasonable.

But that would But that would involve modifying involve modifying the DNA of specific the DNA of specific genes in order for it genes in order for it to be inherited.to be inherited.

Came up with

We know Lamarck’s We know Lamarck’s Inheritance of Acquired Inheritance of Acquired CharactersCharacters doesn’t work doesn’t work becausebecause

When the tails of dogs When the tails of dogs are cut off, the “docked” are cut off, the “docked” look is never inherited look is never inherited by their puppies. by their puppies.

Seeds from trained Seeds from trained bonzai trees always bonzai trees always produce offspring produce offspring that grow to normal that grow to normal size. size.

and children of and children of body builders are body builders are not born looking not born looking like Arnold like Arnold SchwartzneggerSchwartznegger

Evolution HistoryEvolution History

Evolution Part Evolution Part III:III:

Darwin sets Darwin sets sail on the HMS sail on the HMS

Beagle.Beagle.

Darwin goes sailingDarwin goes sailing

In 1831 Charles Darwin, a In 1831 Charles Darwin, a 22 year-old college 22 year-old college graduate set sail as graduate set sail as Captain’s companion on the Captain’s companion on the HMS Beagle for a voyage HMS Beagle for a voyage around the world. around the world. The main mission of the The main mission of the voyage was to chart poorly voyage was to chart poorly known stretches of the known stretches of the South American coastline South American coastline for the British Navy. for the British Navy.

Darwin goes sailingDarwin goes sailingDarwin’s main interest Darwin’s main interest was to study the was to study the geology, plants, and geology, plants, and animals encountered animals encountered on the voyage. on the voyage.

It was a tour that It was a tour that would greatly affect would greatly affect Darwin’s thinking and Darwin’s thinking and eventually the eventually the thinking of others. thinking of others.

Darwin sees the worldDarwin sees the worldThe map below shows the route the ship The map below shows the route the ship followed. followed.

Darwin’s ObservationsDarwin’s ObservationsDarwin spent most of his Darwin spent most of his time on shore while the time on shore while the ship’s crew was busy ship’s crew was busy surveying. surveying. There, he observed and There, he observed and collected thousands of collected thousands of specimens of South specimens of South American plants and animals American plants and animals from diverse environments. from diverse environments.

Darwin’s ObservationsDarwin’s Observations

He studied organisms and He studied organisms and their adaptations from places their adaptations from places as different asas different as

-the Brazilian jungle-the Brazilian jungle

-the grasslands of -the grasslands of the pampasthe pampas

-and the frigid lands -and the frigid lands near Antarctica.near Antarctica.

Darwin’s ObservationsDarwin’s ObservationsThroughout the voyage Throughout the voyage and the rest of his life, and the rest of his life, Darwin maintained Darwin maintained extensive journals of his extensive journals of his observations, studies, and observations, studies, and thoughts. thoughts. These journals provide a These journals provide a window into Darwin’s window into Darwin’s thinking. thinking.

Darwin’s mindsetDarwin’s mindset

Before the voyage Darwin felt Before the voyage Darwin felt that the concept of fixed or that the concept of fixed or unchanging species best unchanging species best described nature. described nature.

During the voyage, he began During the voyage, he began questioning this concept. questioning this concept. Sometime after he returned Sometime after he returned to England, Darwin became to England, Darwin became convinced that species convinced that species change as they adapt to change as they adapt to their changing their changing environments. environments.

Fixed species

Of a South American flavorOf a South American flavor

Darwin noticed on his Darwin noticed on his voyage that the South voyage that the South American plants and animals American plants and animals were quite different from were quite different from the species of Europe.the species of Europe.Even the fossils Even the fossils Darwin found were Darwin found were uniquely South uniquely South American. American. Some of the fossils Some of the fossils were gigantic versions were gigantic versions of the modern of the modern animals. animals.

Extinct Giant Sloth 3000 Extinct Giant Sloth 3000 kgkg

Common Sloth 6 Common Sloth 6 kgkg

The Galapagos The Galapagos ArchipelagoArchipelago

His observations His observations supported the idea that supported the idea that species living in South species living in South America today were America today were descended from descended from ancestral species on ancestral species on that continent. that continent. For example, The For example, The camelids of South camelids of South America were believed to America were believed to have descended from the have descended from the long extinct camelid long extinct camelid Poebrotherium wilsoni. Poebrotherium wilsoni.

The Galapagos The Galapagos ArchipelagoArchipelago

Darwin was also Darwin was also intrigued by life on intrigued by life on islands such as the islands such as the Galapagos. Galapagos.

The Galapagos are a chain The Galapagos are a chain of relatively young volcanic of relatively young volcanic islands about 900 km off the islands about 900 km off the western coast of South western coast of South America. America.

Life on the Galapagos Life on the Galapagos

Darwin observed that the Darwin observed that the islands had many unique islands had many unique organisms.organisms.For example, Galapagos For example, Galapagos iguanas are unique because iguanas are unique because they swim in the ocean to they swim in the ocean to feed on algae. feed on algae.

Life on the Galapagos Life on the Galapagos He observed that even He observed that even the individual islands in the individual islands in the chain had some the chain had some different species of different species of plants and animals plants and animals from one another.from one another.

For example, Galapagos is For example, Galapagos is famous for these unique, famous for these unique, long-necked giant land long-necked giant land tortoises whose shell tortoises whose shell patterns differ from island patterns differ from island to island.to island.

Life on the Galapagos Life on the Galapagos Darwin inferred from Darwin inferred from these observations that these observations that mainland species had mainland species had changed after they changed after they colonized the islands colonized the islands and adapted to their and adapted to their various new various new environments.environments.Case in point: All Case in point: All South American South American cormorant species cormorant species can fly, but the can fly, but the Galapagos Galapagos cormorant is cormorant is flightless.flightless.

GalapagoGalapagoss

S. S. AmericaAmerica

Evolution HistoryEvolution History

Evolution Part Evolution Part IV:IV:

Darwin begins Darwin begins to change his to change his world view.world view.

Catching up on some readingCatching up on some reading

During the Beagle’s long sails During the Beagle’s long sails between ports, Darwin between ports, Darwin managed to do a lot of managed to do a lot of reading.reading.The writings of the geologist The writings of the geologist Charles Lyell had a particular Charles Lyell had a particular influence on Darwin.influence on Darwin.

Lyle proposed that gradual Lyle proposed that gradual and observable geologic and observable geologic processes such as erosion processes such as erosion could explain the physical could explain the physical features of today’s Earth.features of today’s Earth.

Charles LyellCharles Lyell1797 - 18751797 - 1875

Erosion and EarthquakesErosion and EarthquakesFor instance, the gradual For instance, the gradual erosion of a riverbed over erosion of a riverbed over thousands or millions of years thousands or millions of years can result in a deep, river-can result in a deep, river-carved canyon.carved canyon.A mighty mountain range can A mighty mountain range can be thrust up centimeter by be thrust up centimeter by centimeter by earthquakes centimeter by earthquakes occurring over millions of occurring over millions of years.years.All that was required for an All that was required for an understanding of these understanding of these changes was an Earth far changes was an Earth far older than previously thought.older than previously thought.

Rising landRising land

Darwin personally Darwin personally experienced an earthquake experienced an earthquake while doing field studies in while doing field studies in the Andes Mountains of Chile.the Andes Mountains of Chile.

In a harbor, he observed a In a harbor, he observed a block of land that had been block of land that had been underwater move upward underwater move upward above the water level as a above the water level as a result of the quake.result of the quake.

Seashells on highSeashells on high

He also collected fossils of He also collected fossils of ocean organisms high in the ocean organisms high in the Andes. Applying Lyell’s Andes. Applying Lyell’s ideas, Darwin reasoned that ideas, Darwin reasoned that earthquakes gradually lifted earthquakes gradually lifted the rock bearing those the rock bearing those marine fossils from the sea marine fossils from the sea floor.floor.

Drawing conclusionsDrawing conclusions

The geologic evidence The geologic evidence presented by Lyell and others presented by Lyell and others pointed to two conclusions.pointed to two conclusions.

1.1. The slow processes of The slow processes of mountain building and mountain building and erosion suggested an Earth erosion suggested an Earth that must be very old.that must be very old.

2.2. The slow and gradual The slow and gradual processes occurring over vast processes occurring over vast spans of time could cause spans of time could cause enormous change on Earth.enormous change on Earth.

Darwin would Darwin would eventually apply eventually apply this idea of this idea of gradual change gradual change to the evolution to the evolution of Earth’s life of Earth’s life forms.forms.

Darwin’s Darwin’s CollectionCollection

When Darwin and the When Darwin and the Beagle returned to Beagle returned to England after five years, England after five years, he analyzed his he analyzed his collection and became collection and became convinced that Earth was convinced that Earth was ancient and species can ancient and species can change through time.change through time.

EohippusEohippus

Front foot = 4 Front foot = 4 toes Hind foot = toes Hind foot = 3 toes3 toes

The evolution of the The evolution of the horse is an example of horse is an example of how species can change how species can change over time.over time.

Darwin learned Darwin learned there were larger there were larger and smaller and smaller versions of animals versions of animals living today that living today that lived in the past.lived in the past.

Selective BreedingSelective BreedingDarwin then visited Darwin then visited many farms and many farms and learned how farmers learned how farmers used selective used selective breeding to bring breeding to bring about new varieties about new varieties or species of plants, or species of plants, like those that come like those that come from a common wild from a common wild mustard.mustard.

Selective BreedingSelective BreedingDarwin also learned Darwin also learned how farmers used how farmers used selective breeding to selective breeding to produce new varieties produce new varieties of dog, sheep, pig, of dog, sheep, pig, horse and cattle.horse and cattle.

Darwin wondered if Darwin wondered if nature, like a farmer, nature, like a farmer, could cause a could cause a selective breeding-selective breeding-like effect too.like effect too.

Selective BreedingSelective BreedingOf course, there are some things that Of course, there are some things that selective breeding and evolutionary changes selective breeding and evolutionary changes cannot make.cannot make.

Pigeon FancierPigeon FancierDarwin tried his hand as a pigeon Darwin tried his hand as a pigeon fancier. He was amazed to fancier. He was amazed to occasionally find that when he occasionally find that when he crossed purebred pigeons (like crossed purebred pigeons (like white fantails) he would white fantails) he would occasionally get distinct rock occasionally get distinct rock pigeon markings in the Fpigeon markings in the F22 generation. generation. Darwin believed that despite Darwin believed that despite the great differences the great differences between breeds, all pigeons between breeds, all pigeons were descended from the were descended from the rock pigeon, or common rock pigeon, or common pigeon.pigeon.

xx

Common Common pigeonpigeon

Pigeon FancierPigeon Fancier

Darwin inferred that the Darwin inferred that the rock pigeon is successful rock pigeon is successful in the wild because it in the wild because it adapts well to adapts well to environmental demands. environmental demands.

Darwin also noted that Darwin also noted that domestic “fancy” pigeons, domestic “fancy” pigeons, when released as breeding when released as breeding pairs into the wild, do not pairs into the wild, do not fair well and produce no fair well and produce no successful future successful future generations. generations.

Evolution HistoryEvolution History

Evolution Part Evolution Part V:V:

Darwin Darwin develops his develops his

theory of theory of natural natural

selection.selection.

Thomas Thomas MalthusMalthus

1766 - 18341766 - 1834

In 1838, as Darwin continued In 1838, as Darwin continued to think about the question of to think about the question of how species change, he read how species change, he read an essay on human an essay on human populations written a few populations written a few decades earlier by Thomas decades earlier by Thomas Malthus.Malthus.

Population StudiesPopulation Studies

Feast and FamineFeast and FamineMalthus contended that much Malthus contended that much of human suffering, such as of human suffering, such as disease, famine and disease, famine and homelessness, was due to the homelessness, was due to the human population’s potential human population’s potential to grow.to grow.That is, populations can grow That is, populations can grow much faster than the rate at much faster than the rate at which supplies of food and which supplies of food and other resources can be other resources can be produced.produced.

Struggle for existenceStruggle for existenceDarwin recognized that Darwin recognized that Malthus’ ideas applied to all Malthus’ ideas applied to all species. species. Numbers are kept in check Numbers are kept in check by disease and the fight for by disease and the fight for space.space.Some die from a lack of Some die from a lack of water. water. Some die from lack of food. Some die from lack of food.

Struggle for existenceStruggle for existence

The production of more The production of more individuals than the individuals than the environment can support environment can support leads to a struggle for leads to a struggle for existence.existence.

Some die when they end up Some die when they end up as someone else’s food. as someone else’s food.

Struggle for existenceStruggle for existenceTo prove his point, Darwin To prove his point, Darwin counted the seeds from a counted the seeds from a single orchid plant. single orchid plant.

There were 24,080 seeds. There were 24,080 seeds. That was 24,078 more That was 24,078 more offspring than were needed offspring than were needed to replace the two parents.to replace the two parents.

If each of these seeds grew If each of these seeds grew into a plant and if all of these into a plant and if all of these plants had 24,080 seeds, the plants had 24,080 seeds, the whole world would be knee-whole world would be knee-deep in orchids.deep in orchids.

Struggle for existenceStruggle for existenceBut this is not the case. But this is not the case.

Some seeds are Some seeds are eaten by bugs.eaten by bugs.

Some land on poor soil.Some land on poor soil.

Seedlings become sick or are Seedlings become sick or are crowded out by other plants.crowded out by other plants.

These are the losers in the These are the losers in the struggle for existence.struggle for existence.

Natural SelectionNatural Selection

This concept helped This concept helped Darwin to propose a Darwin to propose a mechanism of mechanism of evolutionary change.evolutionary change.

He called it:He called it:

NATURAL SELECTIONNATURAL SELECTION

Putting it all togetherPutting it all together

Thomas HuxleyThomas Huxley1825 - 18951825 - 1895

In 1844, Darwin wrote a In 1844, Darwin wrote a 200 page essay that 200 page essay that outlined his idea, but he outlined his idea, but he didn’t release it to the didn’t release it to the public.public.He told only a few of his He told only a few of his closest colleagues about closest colleagues about his theory, who his theory, who encouraged him to publish encouraged him to publish his work before someone his work before someone else came to the same else came to the same conclusions. conclusions.

Darwin’s Darwin’s “Bulldog”“Bulldog”

Another sourceAnother source

In 1858, another British In 1858, another British naturalist, Alfred Wallace, naturalist, Alfred Wallace, presented similar presented similar evidence and inferences. evidence and inferences.

Within a month, Darwin Within a month, Darwin and Wallace submitted and Wallace submitted joint papers to the public.joint papers to the public.

Alfred WallaceAlfred Wallace

1823 - 19131823 - 1913

Evolution HistoryEvolution History““It is not the strongest of It is not the strongest of the species that survive, the species that survive, nor the most intelligent, nor the most intelligent,

but the one most but the one most responsive to change.”responsive to change.”

A year later, Darwin A year later, Darwin published his book,published his book,

The Origin of The Origin of Species.Species.

Charles DarwinCharles Darwin

Darwin’s main pointsDarwin’s main points1. Decent with 1. Decent with modificationmodification

Species of organisms Species of organisms living on Earth today living on Earth today descended from ancestral descended from ancestral species. These species. These descendents spread into descendents spread into various habitats over various habitats over millions of years. In these millions of years. In these habitats, they habitats, they accumulated different accumulated different modifications, or modifications, or adaptations, to diverse adaptations, to diverse ways of life.ways of life.

Darwin’s main pointsDarwin’s main points2. Natural 2. Natural SelectionSelection

The process by which The process by which individuals with individuals with inherited inherited characteristics well-characteristics well-suited to the suited to the environment leave environment leave more offspring on more offspring on average than do other average than do other individuals.individuals.

Evolution TimelineEvolution Timeline