chapter17 classification

8/7/2019 Chapter17 Classification

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Chapter 17

Classification

Section 17-1 History of Taxonomy


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Taxonomy is the branch ofbiology that names organisms

according to theircharacteristics andevolutionary history


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Taxonomy organizes the huge

biodiversity (variety of typesof life) of the planet


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Organisms were first classified by Aristotle over

2000 yrs ago! His system classified organisms as either plant

or animal.

Problems with his classification:

1. Some organisms are neither plant or animal2. Common names are different in different regions

(ex. Puma, cougar, and mountain lion are allsame animal

3. Some common names areinaccurate (ex. Jellyfish is not a

fish, seahorse is not a horse)


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Carolus Linnaeus developed a

more organized system ofclassification in the 1700s

This system involves seven levels ofclassification which are still used today


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Levels of classification

Kingdom

Phylum

Class

Order

Family Genus

Species

Memory device:

King

Phillip Came

Over

For Good

Spices


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Some examples (pg. 338)

level Shaggy manemushroom

Bobcat

Kingdom Fungi Animalia

Phylum Basidiomycota Chordata

Class Homobasidiomycetae Mammalia

Order Agaricales CarnivoraFamily Copricaceae Felidae

Genus Coprinus Lynx

species comatus rufus


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Section 17-2 ModernPhylogenetic Taxonomy


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Classification originally based on morphology

Modern taxonomists use this and otherevidence to place organisms on aphylogenetic tree

A phylogenetic tree is a diagram showingevolutionary relationships of organisms


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4 Types of Evidence Help

Scientists make a PhylogeneticTree


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Evidence:1. Morphology, or the appearance of an

organism.

Relatedorganisms willshare

homologousstructures


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Evidence:2. The fossil record

Some fossilsserve as links inconnectingcurrent groups

of organisms.EX: archaeopteryx


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Evidence:3. Embryological patterns of development

By looking at the stages of an organisms

development scientists can see patterns. Ex: all fertilized animal eggs begin to grow

in the same way

Zygote blastula gastrula (read pg 344)


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Evidence: Comparing the number of

differences in DNA, amino acids

and proteins If mutations in sequence occur

regularly scientists can predicthow closely related organisms

are. The more similar the DNAthe more closely related thespecies.


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Cladistics A new system of phylogenetic

classification.

It uses a shared derived characteristicto establish relationships

Ex: amniotic (shelled) egg separates

reptiles and birds from other organismsor hair on mammal


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How toread acladogram

No jaws

Everything else has

jaws


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Section 17-3 Two Modern

Systems of Classification


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Two main systems:

Three Domain and Six Kingdom


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Kingdom Archeabacteria Unicellular (one-celled)

Prokaryotic (no nucleus)

Chemosynthetic (use

carbon chemicals to make energy)

They have different cell membranesthan other organisms

They often live in harsh environments


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Kingdom Eubacteria

Unicellular

Prokaryotic Most use oxygen for

respiration

These are true bacteria: involved indecomposing dead animals and plants,making yogurt, etc.


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Kingdom Protista Unicellular Eukaryotic (has nucleus)

Can be autotrophic (make food orheterotrophic (eat food)

Although in the same kingdom there isa huge variety all very distantly related

Ex: amoebaand euglena


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Kingdom Fungi Multicellular AND UNICELLULAR! oops

Eukaryotic

They are heterotrophic (eat food)specifically they absorb food.

Common fungi: Yeast mushrooms


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Kingdom Plantae

Multicellular Eukaryotic

Autotrophic - Plants use solar energy to

photosynthesize or make food Most plants live on land and reproduce

sexually

Ex: venus fly trap oak tree


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Kingdom animalia Multicellular Eukaryotic

Heterotrophic (eat food) Can live on land or water.

Reproduce sexually

Ex. Coral elephant

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