the theory of evolution and darwin

8/14/2019 The Theory of Evolution and Darwin

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EvolutionEvolution

andandDarwinDarwin


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EvolutionEvolution

The processes

processes that have transformed life on

earth from its earliest formsearliest forms to the vast

diversitydiver

sity that characterizes it today.

A changech

ange in the genes

genes!!!!!!!!!!!!!!!!


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Old Theories of EvolutionOld Theories of Evolution

Jean Baptiste LamarckJean

Baptiste Lamarck(early 1800s) proposed:

The inheritance of acquired characteristicsThe inheritance of

acquired characteristics

He proposed that by using or not using its body

parts, an individual tends todevelopdeve

lopcertain

characteristicscharacteristics, which itpasses

passeson to itsoffspringoffs

pring.


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The Inheritance of AcquiredThe Inheritance of Acquired

CharacteristicsCharacteristics Example:Example:

A giraffe acquired its long neck because its

ancestor stretched higher and higher into thetrees to reach leaves, and that the animals

increasingly lengthened neck was passed on

to its offspring.


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Charles DarwinCharles Darwin

Darwin set sail on the H.M.S. BeagleH.M.S. B

eagle (1831-1836)

to survey the south seas ((mainly South Americam

ainly South America

and the Galapagos Islandsand the G

alapagos Islands)) to collect plants andanimals.

On the Galapagos IslandsG

alapagos Islands,, Darwin observed

species that lived no where else in the world.

These observations led Darwin to write a book.


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Charles DarwinCharles Darwin

Wrote in 1859Wrote in 1859: On the Origin of SpeciesOn the Origin of Species

by Means of Natural Selectionby Means of Natural Selection

Two main points:Two main points:

1.1. Species were not created in their presentSpecies were not created in their present

form, but evolved from ancestral speciesform, but evolved from ancestral species..

2.2. Proposed a mechanism for evolution:Proposed a mechanism for evolution:

NATURAL SELECTIONNATURAL SELECTION


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Natural SelectionNatural Selection

IndividualsIndividuals with favorablefavorabletraitstraits are morelikely to leave more offspring better suited for

theirenvironmentenvironment.

Also known as Differential ReproductionDifferential Reproduction

Example:Example:

English peppered moth (English peppered moth (BistonBiston betulariabetularia))- light and dark phases- light and dark phases
http://tidepool.st.usm.edu/crswr/peppermoths.htmlhttp://tidepool.st.usm.edu/crswr/peppermoths.htmlhttp://tidepool.st.usm.edu/crswr/peppermoths.htmlhttp://tidepool.st.usm.edu/crswr/peppermoths.htmlhttp://tidepool.st.usm.edu/crswr/peppermoths.htmlhttp://tidepool.st.usm.edu/crswr/peppermoths.htmlhttp://tidepool.st.usm.edu/crswr/peppermoths.html


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Artificial SelectionArtificial Selection

The selective breedingselective breeding of domesticated

plants and animals by man.

Question:Question:

Whats the ancestor of the domesticated

dog?

Answer:Answer: WOLFWOLF


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Evidence of EvolutionEvidence of Evolution

1.1. Biogeography:Biogeography:

Geographical distribution of speciesGeographical distribution of species..

2. Fossil Record:2. Fossil Record:

Fossils and the order in which they appearFossils and the order in which they appear

in layers ofin layers ofsedimentary rocksedimentary rock (strongest(strongest

evidence).evidence).


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Eastern Long Necked Turtle


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3.3. TaxonomyTaxonomy::

Classification of life forms.Classification of life forms.

4.4. Homologous structuresHomologous structures::

StructuresStructures that arethat are similarsimilarbecause ofbecause of

common ancestrycommon ancestry (comparative anatomy)(comparative anatomy)


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5.5. Comparative embryologyComparative embryology::

Study of structures that appear duringStudy of structures that appear during

embryonic development.embryonic development.

6.6. Molecular biologyMolecular biology::

DNA and proteins (amino acids)DNA and proteins (amino acids)


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Population GeneticsPopulation Genetics

The sciencescience ofgenetic changegenetic change in

population.

Remember:Remember: Hardy-Weinberg equation.


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PopulationPopulation

A localized group ofindividualsindividuals belonging

to the same speciessame species.


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SpeciesSpecies

individualsindividuals that have the potential to

interbreedinterbreed and produce viableviable offspring.


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Gene PoolGene Pool

The total collection of genescollection ofgenes in a

population at any one time.


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Hardy-Weinberg PrincipleHardy-Weinberg Principle

The conceptconcept that the shuffling of genesshuffling of genes that

occur during sexual reproduction, by itself,

cannot changecannot change the overall genetic makeupof a population.


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This principleprinciple will be maintained in nature

only if all fivefive of the following conditions are

met:

1.1. Very large populationVery large population

2.2. Isolation from other populationsIsolation from other populations

3.3. No net mutationsNo net mutations4.4. Random matingRandom mating

5.5. No natural selectionNo natural selection


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Remember:Remember:

If these conditions are met, the

population is at equilibriumequilibrium.

This means No ChangeNo Change or or NoNo

EvolutionEvolution..

the theory of evolution and darwin

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