http://upload.wikimedia.org/wikipedia/commons/4/44/Haeckel_Prosobranchia.jpg

n

As European civilization grew its people had the curiosity and ambition to explore the edges of the Earth, and across vast oceans and in distant lands they found amazing creatures at once incredibly different to those at home, and yet remarkably the same. There was no explanation for such magnificent diversity and enduring similarity until one man, visiting distant isles, had an incredible revelation . . .

http://www.ronscobie-marineartist.com/Brierholme%20oval.JPG

Evolution:

The process by which species

and populations change over time

Decent with modification . . .

http://www.cambridgeshire.gov.uk/NR/rdonlyres/F3840F96-432F-4D02-ADED-4C791BBBC29E/0/Darwin.jpg

Darwin and Natural Selection

• Variation exists within species

• Organisms produce more offspring than the environment can provide for

• Competition exists among individuals

• Organisms whose variations best fit the environment will survive, reproduce, and pass on their advantageous variations to their offspring

Pojeta, John Jr. and Dale A. Springer 2001

http://upload.wikimedia.org/wikipedia/commons/thumb/7/70/Phylogenetic_tree.svg/800px-Phylogenetic_tree.svg.png

• Geology and the Fossil Record

• Biogeography

• Developmental Biology

• Molecular Biology

Evidence has Been Found in Many Places:

Fossils provide the

dimension of time in the

story of evolution

http://www.gutenberg.org/files/20417/20417-h/images/image158.jpg

Principle of SuperpositionSedimentary rock layers are formed sand grain by sand grain, gravel bit be gravel bit, until a new layer of rock is formed, new layers form on top of older layers, and so the youngest layers are always at the top of a rock formation and the oldest at the bottom.

Interesting to know: Steno was one of the first to recognize fossils when in 1667 recognized the similarity of “tongue stones” to sharks teeth

http://www.ucmp.berkeley.edu/history/steno.html

http://photography.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Photography/Images/POD/s/staircase-escalante-building-522011-xl.jpg

Ayala, Francisco J et al., 2008

Radioisotope Dating

• When radioactivity was discovered, so was a way to measure the age of rocks

• Rocks are made of atoms, some are undergoing radioactive decay

• This means they emit particles and energy at a measurable constant rate

• Measurements can be taken to see how many atoms have decayed, which provides insight into how old the rock is

• This is called the natural clock of geology

http://science.howstuffworks.com/carbon-14.htm/ and http://sps.k12.mo.us/jms/cartoon.htm and http://www.ipj.gov.pl/en/szkolenia/glossaryEN.htm

http://media-2.web.britannica.com/eb-media/90/790-004-A1844BBC.gif

http://www.nzetc.org/tm/scholarly/Bio10Tuat02-fig-Bio10Tuat02_P001a.html

Law of Fossil Succession

• Fossils are the remains of once living organisms

• The vast majority of fossils are the remains of the hard parts of extinct organisms

• The types of fossils found differ because life on Earth has changed

http://labspace.open.ac.uk/file.php/4128/S182_7_005i.jpg

•Fossils are the primary evidence for how species evolved over time

•Hundreds of thousands of fossils show succession of forms over time

•Including fish to amphibian•Amphibian to reptile and reptile to mammal

•Importantly, fossils give consistent evidence of systematic change over time without any reversals

(Ayala, Francisco J et al.2001)

Common StructuresFossils can show homologies between species that show a common ancestor (as can comparative anatomy)

Homologies are structures two or more species have in common though they may not be used for the same purpose

http://www.nap.edu/openbook.php?record_id=6024&page=14 and http://upload.wikimedia.org/wikipedia/commons/6/64/Handskelett_MK1888.png

Whereas useless in this circumstance, these rudiments... have not been eliminated, because Nature never works by rapid jumps, and She always leaves vestiges of an organ, even though it is completely superfluous, if that organ plays an

important role in the other species of the same family.

–Etienne Geoffroy Saint-Hilaire 1798

http://en.wikipedia.org/wiki/%C3%89tienne_Geoffroy_Saint-Hilaire

Developmental Biology

•Evolution is not perfectly efficient

•As new species evolve from old species

they often carry with them old traits

that no longer serve any purpose

•These traits are known as vestigial traits

and can by anatomical, biochemical

or behavioral in nature

•These traits are further evidence of an

ancestral relationship

Blind Mole Rat: Can’t see a thing with their eyes covered by skin flaps, but still has eyes

http://en.wikipedia.org/wiki/Vestigial and http://farm2.static.flickr.com/1166/1186161894_7f69d19604.jpg?v=0

Ostriches: still have wings, but cannot fly

Coccyx: the tailbone of a human, a vestigial attribute from our tailed ancestors

Whale: Note the bones labeled “c,” they are the vestigial memory of hind legs

Biogeography

Biogeography

• There is an enormous amount of diversity, and yet many common forms and migration’s influence on the development of new species

• Explains the multiplicity of related species in remote localities

• Explains the absence of many organisms on islands and multiplicity of a few kinds

Phylogenetic Tree of Galapagos finches

http://porpax.bio.miami.edu/~cmallery/150/unity/c1x17b-finches.jpg

Finches in Context of Migration from Mainland to Island

http://www.doe.mass.edu/mcas/student/2007/question.asp?GradeID=100&SubjectCode=bio_hs&QuestionTypeName=&QuestionID=5357

Molecular Biology

• Provides the mechanism of evolution

• Provides evidence of a common ancestor

• Provides additional information about when speciation occurs and history of relationships between species by examining the molecular clock and pseudogenes

http://www.ch.cam.ac.uk/magnus/molecules/nucleic/dna1.jpg

Mechanism for Evolution• In the year following Darwin, all of this evidence accumulated

in favor of evolution, yet until the discovery of modern genetics, the mechanism for variation was not known

• Greg Mendel first noted patterns in heredity, however with Watson and Crick’s discovery of the double helix we have now come so far as to understand chromosomes, genes and DNA

• DNA is the ultimate source of variation, when sperm, eggs, or daughter organisms are created, the DNA of the parent must be replicated to provide the template of the organism

• When DNA replicates it is not a perfect process and small errors will occur, most are corrected in the process, but some are not, these are mutations

• Mutations provide the variation between individuals within a species necessary for natural selection to occur

http://universe-review.ca/I11-33-mutations.jpg

A Common Basis• All living things share the same

biochemical machinery from algae to elephants

• Proteins are virtually identical from fruit flies to mice to humans and all life uses the same 20 amino acids

• All living things use the same biochemical system to pass genetic information from one generation to another

• This adds enormous weight to the idea of a common ancestor

http://www.ageds.iastate.edu/meat/images/dna2.gif

All living organisms share common structures for DNA, RNA, and the 20 amino acids

http://www.talkorigins.org/faqs/molgen/

Molecular Clock

• Genes have been used to reconstruct the evolutionary history of species

• Mutations occur constantly• Genes evolve at different rates because

some genes are more tolerant to change than others

• When geneticists consider this they can create maps of when species may have diverged

Pseudogenes and Phylogenetic Trees

• As species change some genes that were once useful lose their functionality

• They are still passed on to offspring, but are not expressed, just carried along like excess baggage

• They are useful to determine past relationships between species

• The degree of similarity of these genes between different species reflects the degree of relatedness as it is improbable they evolved independently

Works CitedAyala, Francisco J et al. 2008. Science, Evolution, and Creationism. The

National Academies Press. National Academy of Science and Institute of Medicine. Washington D.C.

Bowler, Peter J. 2003. Evolution: The History of an Idea. University of California Press. Berkley

Gardner, Robert. 2005. Genetics and Evolution Science Fair Projects. Enslow Publishers. Berkeley Heights. 123-124

Krukonis, Greg and Tracy Barr. 2008. Evolution for Dummies. Wiley Publishing, Inc.

Larson, Edward J. 2004. Evolution: The Remarkable History of a Scientific Theory. The Modern Library. New York

Hilaire, Geoffroy.1798. "Observations sur l'aile de l'Autruche, par le citoyen Geoffroy", La Decade Egyptienne, Journal Litteraire et D'Economie Politique 1 (pp. 46–51). Embedded in < http://en.wikipedia.org/wiki/Vestigial#cite_note-3>

Pojeta, John Jr. and Dale A. Springer. 2001. Evolution and the Fossil Record. American Geological Insitute. Alexandria, Virginia <agiweb.org>

Taylor, Paul D. 2000. Eyewitness Books: Fossil. Dorling Kindersley. London