The The Biodiversity of Biodiversity of Life on EarthLife on EarthWhere did it all start?Where did it all start?

How do we keep it all How do we keep it all straight?straight?

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By the end of this By the end of this lesson you will be able lesson you will be able

to:to:• Describe the origin of life on earth*• Explain the Theory of Endosymbiosis*• Describe the role and importance of a taxonomist

• Compare Linnaeus’ classification system with today’s

• Use AND design a cladogram (phylogenetic tree)

*** = Not in this chapter, but need to know!!!!

Happy Birthday Happy Birthday Earth!!!!!Earth!!!!!

• Atmosphere of hydrogen cyanide, carbon dioxide, carbon monoxide, nitrogen, hydrogen sulfide, water vapor

• It was hot!!!!!

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Then what???Then what???• 4 BYA the earth cooled forming solid rock

• 3.8 BYA the water remained in liquid form

• 3.5 BYA prokaryotic ancestors arose

• Oh, but how!?!?!?!• Stanley Miller’s hypothesis

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Next…..Next…..• 2.2 BYA Oxygen gas became part of the atmosphere (photosynthesis)

• 2 BYA Eukaryotic ancestors arose from these

• How???

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Endosymbiotic TheoryEndosymbiotic Theory• What is going on here?– What did we start with?

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And then?And then?

• Eukaryotic cells began sexual reproduction speeding up

evolution• Multicellular life began in the sea

• ~500 MYA the “Cambrian Explosion” occurred - diversification of life

• Today - More than 150 million species identified, leaving around 2-10 million yet to be discovered

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How do we keep track of How do we keep track of them all????them all????

• How do you keep track of your….

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Classification - the science of taxonomy; allows us to use a common language

Carolus LinnaeusCarolus LinnaeusQuickTime™ and a

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• 18th Century Swedish Botanist• Classification system still used today

• Introduced binomial nomenclature– Two part Latinized name - italicized or underlined1st part - Genus - capitalized2nd part - species epithet - lower case

Ex: Fundulus heteroclitus or F. heteroclitus Escherichia coli or E.coli

Linnaeus’s Classification Linnaeus’s Classification SystemSystem

• Hierarchal (levels)

• Starts out broad and gets specific

• Narrows it down to one organism

• Still used today, but slightly changed to reflect evolutionary relationships

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Evolutionary Evolutionary ClassificationClassification

• The study of phylogeny• Groups organisms that have a common ancestor together

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Cladogram/Phylogenetic Cladogram/Phylogenetic TreeTree

• Groups organisms based on evolutionary relationships

• Uses shared derived characters - characteristics that arise over time and are shared by recent groups and not by the older groups

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CladogramCladogram

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Shared

Derived

Character

Classwork:Classwork:1) Construct a cladogram with the

organisms in the table2) Identify the organism that is

least closely related to the others

Shared Derived Character Chart

Organisms Backbone Legs Hairs

Earthworm Absent Absent Absent

Trout Present Absent Absent

Lizard Present Present Absent

Human Present Present Present

Now, its your turn….Now, its your turn….1) Choose a category of objects or activities2) Place them into different groups based on

characteristics they share3) Make a table, like the previous one to

help arrange your groups4) On one side of paper, Your table should

include AT LEAST 5 different groups in the first column and 4 shared derived characters in the first row

5) On the other side, Design a cladogram using your approved chart. Give it a title, make it colorful, creative and easy to read!!!! It will be due…

Your CladogramYour Cladogram• Use graph paper to complete your table and rough draft in-class now.

• Check your table with me and then start your rough draft on the back of the paper.

• Final draft due Wednesday April 6th.

Today’s ClassificationToday’s Classification• Using genetics to help us out!!!

• Similar genes = ???• More similar genes = a more recent common ancestor

• Genes used to eliminate confusion based on physical similarities alone

Molecular clock modelMolecular clock model• DNA comparisons can be used to measure evolutionary time

• Relies on known mutation rates• Used to estimate how long two species have been separated

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Our Current SystemOur Current System• 3 Domains - Bacteria, Archaea, and Eukarya

• 6 Kingdoms - Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animala

• Use graph paper and rulers to make and fill in the table for a reference sheet to be used for the next few chapters

Classification chartClassification chart

Domains KingdomsCell Type

# of Cells

Nutrition Mode

Examples

Bacteria

Archaea

Eukarya