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Classification-pg. 70
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What is Classification?
What classification systems are you familiar with and use?
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Benefits of Classifying
• Accurately & uniformly names organisms
• Prevents misnomers such as starfish & jellyfish that aren't really fish
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Sea”horse”??
Carolus Linnaeus
• Developed the modern system of naming known as binomial nomenclature
• Two-word naming system (Genus & species). Capitalize genus, not species
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Binomial Nomenclature
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Which TWO are more closely related?
Classification Groups• Taxon ( taxa-plural) is a
category into which related organisms are placed
• There is a hierarchy of groups (taxa) from broadest to most specific: • Domain (broadest Kingdom
Phylum Class Order Family Genus species (most specific)
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Break it DOWN:
Domain EukaryaKingdom AnimaliaPhylum ChordataClass MammaliaOrder PrimatesFamily HominidaeGenus HomoSpecies sapiens
◦Homo sapiens
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Domains
• Three domains:• Archaea and Eubacteria are
unicellular prokaryotes (no nucleus or membrane-bound organelles)
• Eukarya are more complex and have a nucleus and membrane-bound organelles
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ARCHAEA• Probably the 1st cells to evolve• Live in HARSH environments• Found in:
–Thermal or Volcanic Vents–Hot Springs or Geysers that are
acid
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An ARCHAEAN
EUBACTERIA• Found in ALL HABITATS except
harsh ones• Important decomposers for
environment• Commercially important in
making yogurt, buttermilk, etc.
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Live in the intestines of animals
Domain Eukarya is Divided into Kingdoms
• Protista • Fungi • Plantae • Animalia
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Protista•Most are unicellular, some multicellular•Some are autotrophic, while others are heterotrophic•Aquatic•Ex: Algae
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Fungi• Multicellular,
except yeast• Absorptive
heterotrophs (digest food outside their body & then absorb it)
• Cell walls made of chitin
• Ex: Mushroomscopyright cmassengale 15
PlantaeEx: Trees,
flowers
•Multicellular
•Autotrophic (absorb sunlight to make glucose)•Cell walls made of cellulose
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Animalia• Multicellular• Ingestive
heterotrophs (consume food & digest it inside their bodies)
• Feed on plants or animals
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Domain Kingdom
Bacteria Eubacteria
Archaea Archaebacteria –No peptidoglycan
Eukarya Animals Plants Fungi Protists
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Classification is based on evolutionary relationships
How is the hierarchy like a time machine?◦The higher the level, the further back in
time that common ancestor existed.
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How does Linnaeus’ system of classification help to illustrate the unity of life?We see the similarities and the
differences. Organisms in the same genus share many features, while those in the same kingdom have many differences, but still share common traits.
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Primate Cladogram
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Basis for Modern Taxonomy• Homologous structures Similar embryo development
• DNA, RNA
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Homologous Structures (BONES in the FORELIMBS) shows Similarities in mammals.
What’s Cladistics?The classification based on
common ancestry. The goal of cladistics is to place species in order in which they descended from a common ancestor.
VS.
VS.
CladogramDiagram showing how organisms are related
based on shared, derived characteristics such as feathers, hair, or scales
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Cladogram:Derived characters-groups of
species placed in order by the characters (traits) that have added up over time. They are shown as dash marks between the branches of a cladogram. All species above a dash mark share the derived character.
Dichotomous Keys• Used to identify organisms• Characteristics given in pairs
• Read both characteristics and either go to another set of characteristics OR identify the organism
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Example of a Dichotomous Key
1a Tentacles present – Go to 21b Tentacles absent – Go to 32a Eight Tentacles – Octopus2b More than 8 tentacles – 33a Tentacles hang down – go to 43b Tentacles upright–Sea Anemone4a Balloon-shaped body–Jellyfish4b Body NOT balloon-shaped - 5
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1. What is more closely related to a wolf: turtle or salamander?
2. What characteristics do the grouper, salamander, turtle, and wolf share?
