CHAPTER THREECHAPTER THREE

EVOLUTIONEVOLUTION

HISTORY AND EVIDENCEHISTORY AND EVIDENCE

Pre~Darwinian Theories of Pre~Darwinian Theories of ChangeChange

The idea of evolution did not The idea of evolution did not originate with Charles Darwin.originate with Charles Darwin.

Darwin’s Early Years and His Darwin’s Early Years and His Journey Journey

At the age of 16 he entered medical At the age of 16 he entered medical school in Edinburgh, Scotlandschool in Edinburgh, Scotland

During his stay at Cambridge, Darwin During his stay at Cambridge, Darwin developed a keen interest in developed a keen interest in collecting beetles and made collecting beetles and made valuables contribution to beetle valuables contribution to beetle taxonomytaxonomy

Early Development of Darwin’s Early Development of Darwin’s Ideas of EvolutionIdeas of Evolution

Darwin’s theory of evolution by natural Darwin’s theory of evolution by natural selection was long, painstaking process.selection was long, painstaking process.

Darwin had to become convinced that Darwin had to become convinced that change occurs overt timechange occurs overt time

During his voyage suggested that During his voyage suggested that change occur, he realized the 6000 change occur, he realized the 6000 years could not account for the years could not account for the diversity of modern species if they diversity of modern species if they arose through gradual changearose through gradual change

GeologyGeology

Lyell developed the ideas of another Lyell developed the ideas of another geologist, James Hutton, into the geologist, James Hutton, into the theory of uniformitarianism theory of uniformitarianism

His theory was based on the idea His theory was based on the idea that the forces of wind, rain, rivers, that the forces of wind, rain, rivers, volcanoes, and geological uplift volcanoes, and geological uplift shape the earth today, just as they shape the earth today, just as they have in the past.have in the past.

Fossil EvidenceFossil Evidence

Once the HMS Beagle reached South Once the HMS Beagle reached South America, Darwin spent time digging America, Darwin spent time digging in the dry riverbeds of the pampas in the dry riverbeds of the pampas (grassy plains) of Argentina(grassy plains) of Argentina

He found the fossil remains of an He found the fossil remains of an extinct hippopotamus like animal, extinct hippopotamus like animal, now called Toxodon, and fossil of a now called Toxodon, and fossil of a horselike animal, Thoantheriumhorselike animal, Thoantherium

Natural SelectionNatural Selection

Natural SelectionNatural Selection

Charles Darwin had no knowledge of Charles Darwin had no knowledge of modern genetic concepts and modern genetic concepts and therefore, had no knowledge of the therefore, had no knowledge of the genetics principles that are the the genetics principles that are the the basic of evolutionary theory as its basic of evolutionary theory as its exists todayexists today

Adaptation Adaptation

Occurs when a change in a Occurs when a change in a phenotype increases an animals phenotype increases an animals chance of successful reproduction.chance of successful reproduction.

Adaptation sometimes used of the Adaptation sometimes used of the term is probably less confusing ran term is probably less confusing ran when it is used to describe the result when it is used to describe the result of the process of changeof the process of change

Alfred Russell WallaceAlfred Russell Wallace

He was an explorer of the Amazon He was an explorer of the Amazon valley and the led a zoological valley and the led a zoological expedition to the Malay archipelago expedition to the Malay archipelago

Wallace like Darwin was impress with Wallace like Darwin was impress with the evolution change and had the the evolution change and had the writing of Thomas Malthus o human writing of Thomas Malthus o human populationspopulations

Microevolution, Macroevolution, Microevolution, Macroevolution, and Evidence of and Evidence of

Macroevoluntionary ChangeMacroevoluntionary Change

A change in the frequency of alles in A change in the frequency of alles in population over time is called population over time is called microevolutionmicroevolution

The processes that result in The processes that result in microevolution are discussed..microevolution are discussed..

BiogeographyBiogeography

Is the study of the geographic Is the study of the geographic distribution of plants and animals.distribution of plants and animals.

They studied show that life forms in They studied show that life forms in different parts of the world have different parts of the world have distinctive evoluntionary historiesdistinctive evoluntionary histories

PaleontologyPaleontology

Which is the study of the fossil record Which is the study of the fossil record provides some of the most direct provides some of the most direct evidence for evolutionevidence for evolution

Analogy and HomologyAnalogy and Homology

The evolution of superficially similar The evolution of superficially similar structures in unrelated organism is structures in unrelated organism is called convergent evolutioncalled convergent evolution

Structure and processes in two kind Structure and processes in two kind of organisms that are derived from of organisms that are derived from common ancestry are said to be common ancestry are said to be homologoushomologous

Development PatternsDevelopment Patterns

Evidence of evolution also comes Evidence of evolution also comes from observing the development from observing the development pattern of organismpattern of organism

Interpreting the Evidence: Interpreting the Evidence: Phylogeny and Common Phylogeny and Common

DescentDescent

Phylogeny refers to the evolutionary Phylogeny refers to the evolutionary relationship among speciesrelationship among species