 Classification - the grouping of objects or information based on similarities.
 Used to better understand and study the enormous variety of living things.


-The branch of biology that groups and names organisms based on studies of their different characteristics.

 Based on a system developed by Carolus
Linnaeus .
 He established a system of groups called
Taxa (Taxons)
 He ranked taxa from the largest , most general groups to the smallest , most specific groups.

 Organisms are grouped into taxon
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King-
Philip-
Came-
Over -
Kingdom
Phylum
Class
Order
For -
Good-
Family
Genus
SpaghettiSpecies

 At each level, organisms that share the most characteristics are grouped.
 Species is the most s pecific. (members of the same species can produce offspring.)
 Kingdom - is the most general.
 NOTE: THE PLANT KINGDOM IS DIVIDED INTO DIVISIONS
INSTEAD OF PHYLA.

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Carolus Linnaeus’ classification system: in 18th century
Divided organisms into 2 groups: plants
& animals
Placed plants & animals into groups based on similarities of form (shape, structure)

 Has groups within larger groups within still larger groups
 Uses unique (one-of-a-kind), descriptive
Latin names as scientific names for each organism
• Bats fly like birds, but have hair and produce milk

Therefore bats are mammals and not birds

 Crawdad, Crayfish, Mudbug

What is the difference?
 Scientists need a universal name for every organism.
 He proposed a system of naming using 2 names ; this system is called
Binomial nomenclature

 The 2 names for each organism are:

Genus - always first and capitalized; can be abbreviated to 1 letter.
 species - second and lowercase
**** Both are underlined or italicized***
 HumansHomo sapiens
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HomoGenus sapiens“Wise”

1.
2.
3.
Archae
Eubacteria
Eukarya

 How evolutionary relationships are determined:
Today the most generally accepted classification system contains six kingdoms :
 Archaebacteria
 Eubacteria
 Protists
 Fungi
 Plants
 Animals

 These kingdoms are then broken down into smaller categories.
 Characteristics that scientists use to classify the relationships of organisms include:
 structural similarities
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 breeding behavior geographical distribution chromosome comparison biochemistry

 Dichotomous Key: made of sets of numbered statements; each set deals with 1 trait of the organism; follow the numbered sets until the key reveals the name of the organism.

 Phylogeny- The evolutionary history of a species.

Also shows evolutionary relationships of species

 Cladistics: system of classification based on phylogeny (evolutionary history of a species)

 Cladogram: branching diagram that models the phylogeny of a species, resembles a pedigree or family tree showing proposed ancestry of the species.

 1. What five probable ancestors of the modern bird (robin) are shown on the cladogram?
Answer to #1
• Archaeopteryx
• Velociraptor
• Sinornis
• Allosaurus
• Theropods

 2. Which dinosaur is probably the most recent common ancestor of Velociraptor and Archaeopteryx ?
Answer to #2:
Sinornis

 3. Which traits shown on the cladogram are shared by Archaeopteryx and modern birds?
Answer to #3
Light bones, 3-toed foot, Wishbone, down feathers, and feathers with shaft, veins, and barbs

Fan-like model can show time organism became extinct, or the relative number of species in a group (evolutionary history)

 1. How does the fanlike diagram differ from a cladogram?
Answer to #1
Cladograms provide phylogenetic relationships among species.
Fanlike diagrams communicate the time organisms became extinct or the relative number of species in a group.

 2. To which group are sea stars more closely related, arthropods or jellyfishes?
Answer to #2 arthropods

 3. Which group of animals includes the fewest species?
Answer to #3
Sea Stars
(Echinoderms)

 As scientists began to learn more about geologic time, they incorporated their findings in their systems of classification.
The new system that accounted for an organism’s evolutionary history is called-
 A. Binomial nomenclature
 B. Phylogeny
 C. Taxonomy
 D. None of the above
B. phylogeny

 What does a fanlike diagram show that a cladogram does not?
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A. Phylogenetic relationships
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B. Relative number of species in each group
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C. Anatomical features of each species
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D. Mode of extinction
B. Relative number of species in each group