1. history of evolution

7/31/2019 1. History of Evolution

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History of evolution

commons.wikimedia.org/wiki/Image:Charles_Darwin_1881.jpgcommons.wikimedia.org/wiki/Image:DNA_double_helix_vertikal.PNG



History of Evolution1. World without evolution

2. Evolution of evolution

3. Synthesis between Genetics and Evolution

4. Evolution in the age of DNA

5. Evolution in the age of genomes



World without Evolution

(Discovery1: fixed species)Creations & religions --- Creationism

Egyptian mythology Christian mythology Chinese mythology

Aztec mythology

Babilonians Mathematical EquationsHindu mythology



Why was Creationism

questioned?Annals of the Old Testament, Deduced from the First

Origins of the World- Bishop James Ussher Creation began at nightfall before Sunday, Oct 23, 4004 B.C.E.

Age of earth ~6000 years gives very little time forchange

Many geologists started suspecting that earth must bemillions of years old



Geologists postulate an

ancient earthUniversity of Edinburgh-Scotland became a center for geology-James Hutton

By the mid-19th century geologists had worked out the

1. major geological periods in the history of the Earth and assembleddiagrams showing strata in their historical order.

2. Each layer contained a unique set of fossils, which helped biologistsunderstand how the types and forms of life had changed over immensestretches of geological time



Discovery (2): Fossils and Stratahttp://en.wikipedia.org/wiki/ ImageWilliam_Smith.g.jpg

http://en.wikipedia.org/wiki/Image:Geological_map_of_Great_Britain.jpg

http://en.wikipedia.org/wiki/Image:Smith_fossils2.jpg

William Smith, his geology map & some of his fossil specimens

At about the same time, geologists like William Smith weremapping the rocks and fossils of Britain. He and others showed

that different species existed in the past compared with today.



Smith and others were able to show that

1. rocks were laid down in a certain order

2. different fossils in different layers lived at

different intervals of geological time.

3. Here was clear evidence that different

species had existed in the past compared

with today.

However, Smith did not go on to ask thequestion, „Why?‟ or to consider that this

might be evidence for evolution.



Evolution of evolution:

Discovery (3): Transmutation

en.wikipedia.org/wiki/Image:Giraffe_standing.jpg

commons.wikimedia.org/wiki/Image:Jean-baptiste_lamarck2.jpg

Jean Baptiste de Lamarck

• Around 1800, scientists began towonder whether species could

change or transmute.• Lamarck thought that if an animalacquired a characteristic during itslifetime, it could pass it onto its

offspring.

• Hence giraffes got their long necksthrough generations of straining to

reach high branches.



Evolution of evolution:

Discovery (3): Transmutation

Étienne Geoffroy Saint-Hilaire (1772 –1844)

National Museum of National History



Discovery (4): Darwin‟s Voyage

en.wikipedia.org/wiki/Image:Charles_Darwin_by_G._Richmond.jpgen.wikipedia.org/wiki/Image:HMS_Beagle_by_Conrad_Martens.jpg

Voyage of the Beagle

• From 1831-1836, ayoung naturalist calledCharles Darwin touredthe world in HMSBeagle.

• He was dazzled by the

amazing diversity oflife and started towonder how it mighthave originated



Discovery (5): Survival of the Fittest

en.wikipedia.org/wiki/Image:Darwin%27s_finches.jpeg

• In his Origin of Species,published in 1859, Darwinproposed how one species

might give rise to another.

• Where food was limited,competition meant that onlythe fittest would survive.

• This would lead to the natural selectionof the best adapted individuals andeventually the evolution of a new species.

Darwin in 1860

Natural Selectionexplains adaption



Discovery (6): Huxley v. Wilberforce

www.bbc.co.uk/religion/galleries/spiritualhistory/images/9.jpg

• Darwin‟s idea of Evolution by NaturalSelection was met with

huge controversy.• A famous debate in1860 pitted BishopWilberforce againstDarwin‟s bulldog, Thomas Henry Huxley.Bishop Wilberforce v. T. H. Huxley

• Evolutionists got the better of the debate, but few were convincedby Darwin‟s idea of Natural Selection.



Who coined the term“Evolution”



Mendelian Genetics

Discovery (7)



Attempts to link Genetics &

Evolution1. Matthias Schleiden (1804 –81) and Theodor Schwann

(1810 –82): Cell

2. Discovery of chromosomes

3. August Weismann(1834 –1914): Meiosis

4. Translation of Mendel‟s work: Mendel’s Principles of Heredity: A Defence (1902) by Bateson

5. Garrod proved Mendel‟s laws in humans.

6. Morgan‟s famous mutation experiments on Drosophila melanogaster Morgan



Discovery (8): Population Genetics• In the early 20th century, scientist started tomake sense of how evolution worked.

• Building on Mendel‟s genetics, studies

showed how characteristics in a populationcould be selected by environmentalpressures.

• This Modern Synthesis, as Julian Huxleycalled it, brought Darwin‟s Natural Selection

back to the centre of evolutionary theory.

Hardy, Weinberg, Haldane, Fischer and Wright Were pioneers of Population Genetics

en.wikipedia.org/wiki/Image:Hux-Oxon-72.jpg

Julian Huxleyand the

Modern Synthesis



Discovery of DNA



Central Dogma of Life



New theories on origin of life

DNA from fossils also provided substantial evidence



The Tree of Life

en.wikipedia.org/wiki/Image:Phylogenetic_tree.svg

• All living things share a commonancestor.

• We can draw a Tree of Life toshow how every species is related.



Genome sequencing

chronologyYear Organism Significance Genomesize (bp)

Numberof genes

1977BacteriophagefX174

First genomeever!

5,386 11

1981Humanmitochondria

First organelle 16,500 37

1995Haemophilus influenzae Rd

First free-living

organism

1,830,137 ~3,500

1996Saccharomyces cerevisiae

Firsteukaryote

12,086,000 ~6,000

http://www.ncbi.nlm.nih.gov/ICTVdb/Images/Ackerman/Phages/Microvir/238-27_1.jpg

http://www.alsa.org/research/article.cfm?id=822http://www.waterscan.co.yu/images/virusi-bakterije/Haemophilus%20influenzae.jpghttp://www.biochem.wisc.edu/yeastclub/buddingyeast(color).jpg

http://www.ncbi.nlm.nih.gov/ICTVdb/Images/Ackerman/Phages/Microvir/238-27_1.jpg



Genome sequencingYear Organism SignificanceGenome size(bp)

Numberof genes

1998Caenorhab-

ditis elegans

First multi-cellular

organism

97,000,000 ~19,000

1999Humanchromosome22

First humanchromosome

49,000,000 673

2000 Arabidopsis thaliana

First plantgenome 150,000,000 ~25,000

2001 HumanFirst humangenome

3,000,000,000 ~30,000

http://www.sih.m.u-tokyo.ac.jp/chem1.gif

http://lter.kbs.msu.edu/Biocollections/Herbarium/Images/ARBTH3H.jpg

http://shiulab.plantbiology.msu.edu/wiki/images/8/8a/DSCN3107.jpg



So where are we heading?

Jo Handelsman

Synthetic Cell Metagenomics

http://www.google.co.in/imgres?imgurl=http://meetthescientist.files.wordpress.com/2009/04/handelsmancourtesyuniversityofwisconsin-madison.jpg&imgrefurl=http://meetthescientist.wordpress.com/2009/04/10/&usg=__KqojZ-kG9FZUZAQBNiLgwgmj76M=&h=1031&w=905&sz=343&hl=en&start=1&um=1&itbs=1&tbnid=uYKex1S24v-QDM:&tbnh=150&tbnw=132&prev=/images%3Fq%3Djo%2Bhandelsman%26um%3D1%26hl%3Den%26safe%3Doff%26sa%3DX%26tbs%3Disch:1



Understood……….

So, What is Evolution?

http://images.google.co.in/imgres?imgurl=http://blog.tystoybox.com/wp-content/uploads/2009/08/super-why-action-fig.jpg&imgrefurl=http://blog.tystoybox.com/category/kid-stuff/&usg=__yQMIURMld1Q0Q4AG5-cfFDiBTSM=&h=500&w=500&sz=49&hl=en&start=87&um=1&itbs=1&tbnid=8cpC8YXLHOIrEM:&tbnh=130&tbnw=130&prev=/images%3Fq%3Dwhy%26start%3D84%26um%3D1%26hl%3Den%26safe%3Doff%26sa%3DN%26ndsp%3D21%26tbs%3Disch:1



Evidences of Evolution



Evidence (1): Biochemistry

en.wikipedia.org/wiki/Image:ATP-xtal-3D-sticks.png

DNA forInformation

Transfer

ATP forEnergy

Transfer

• The basic similarity of all living things suggeststhat they evolved from a single common ancestor.

• As we have already seen, all living things passon information from generation to generationusing the DNA molecule.

• All living things also use a moleculecalled ATP to carryenergy around theorganism.



Evidence (3): Comparative Anatomy

en.wikipedia.org/wiki/Image:Primatenskelett-drawing.jpg

Human and Gorilla

• Similar comparisons can be madebased on anatomical evidence.

• The skeleton of humans andgorillas are very similar suggestingthey shared a recent commonancestor, but very different from themore distantly relatedwoodlouse…

yet all have a commonshared characteristic:

bilateral symmetry Woodlouse



Evidence (4): Homology

en.wikipedia.org/wiki/Image:Evolution_pl.png

The pentadactyl limbis ancestral to allvertebrates…

but modified for different uses



Evidence (5): Vestigial Structures

en.wikipedia.org/wiki/Image:Illu_vertebral_column.jpg

The coccyx is a vestigial tail

• As evolution progresses, somestructures get side-lined as theyare not longer of use. Theseare known as vestigial structures.

• The coccyx is a much reducedversion of an ancestral tail, which

was formerly adapted to aidbalance and climbing.

• Another vestigial structure in

humans is the appendix.



Evidence (7): Transitional fossils

en.wikipedia.org/wiki/Image:Archaeopteryx_lithographica_paris.JPG

Archaeopteryx

• Many fossils show a cleartransition from one species,or group, to another.

• Archaeopteryx was foundin Germany in 1861. Itshare many characteristicswith both dinosaurs andbirds.

• It provides good evidencethat birds arose from

dinosaur ancestors



Evidence (9): Antibiotic resistanceStaphylococcus• We are all familiar withthe way that certainbacteria can becomeresistant to antibiotics

• This is an example of natural selection in

action. The antibiotic acts as anenvironmental pressure. It weeds outthose bacteria with low resistance andonly those with high resistance surviveto reproduce.

1. history of evolution

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