unit 11: classification of living things
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Unit 11: Classification of Living Things
Tacitus bellus
Populus tremuloides
Quaking Aspen
Finding Order in Diversity• To study the diversity of life,
biologists use a classification system to name organisms and group them in a logical manner.
• Taxonomy is the branch of biology that groups and names organisms based on studies of their different characteristics.
• Biologists who study taxonomy are called taxonomists.
• Classification systems change with expanding knowledge.
Carolus von Linnaeus(1707-1778)
Carolus Linnaeus• Swedish botanist• Developed Binomial
Nomenclature• Two-word naming system
– Genus» Noun, Capitalized,
Underlined or Italicized– Species
» Descriptive, Lower Case, Underlined or Italicized
– Each species is assigned a two-part scientific name
» Ex. Ursus arctos
System of Classification• Linnaeus’s hierarchical system of
classification includes eight levels (from largest to smallest)
• Grizzly Bear (common name)– Domain Eukarya– Kingdom Animalia– Phylum Chordata– Class Mammalia– Order Carnivora– Family Ursidae– Genus Ursus– Species arctos
Each of the levels is called a TAXONUrsus
arctos(scientific name)
System of Classification• Taxonomic categories, an
acronym:– Domain Dear– Kingdom King– Phylum Phillip– Class Came– Order Over– Family For– Genus Good– Species Soup
KKPPCCOOFFGGSS
Use the table to complete the worksheet
WorksheetWorksheet
• Phylogeny – evolutionary relationships among organisms
• Evolutionary classification – strategy of grouping organisms together based on their evolutionary history– Fossil record– Comparative homologies– Comparative sequencing of
DNA/RNA among organisms– Molecular clocks
Evolutionary Classification
Molecular Clock
Allows scientist to compare DNA sequences form two species to estimate how long it has been since they diverged from a common ancestor
Taxonomic Diagrams
Phylogenetic Tree: Represent hypothesized evolutionary relationships
Mammals Turtles Lizards and Snakes Crocodiles Birds
Looks like aBranch on a
tree
Attempt to trace the process of evolution by
focusing on shared features
Mammals Turtles Lizards and Snakes Crocodiles Birds
CladogramTaxonomic Diagrams
Which organism is the outgroupMammals
Which 2 organism are more closely related
Crocodiles and birds
Refer to page 496 to 497WorksheetWorksheet
Dichotomous Keys Identify Organisms • Dichotomous keys contain pairs of
contrasting descriptions.• After each description, the key directs
the user to another pair of descriptions or identifies the organism.
Example: 1. a) Is the leaf simple? Go to 2b) Is the leaf compound? Go to 32. a) Are margins of the leaf jagged? Go to 4b) Are margins of the leaf smooth? Go to 5
WorksheetWorksheet
Classification of Living Things
Domains (Notice the domains on the chart)
• Most inclusive category • Larger than a kingdom• There are 3
– Eukarya – includes the kingdoms»Protists, Fungi, Plants &
Animals– Bacteria – corresponds to the
kingdom Eubacteria– Archaea – corresponds to the
kingdom Archaebacteria
Slides 17-23
•Is more specific with the classification
Kingdoms• (Eubacteria and Archaebacteria)
Prokaryotes, with or without peptidoglycan in cell walls
• Protista – Eukaryotes, diverse, not fungi, plants, or animals
• Fungi – Eukaryotes, multicellular (except yeasts), heterotrophic, chitin in cell walls
• Plantae – Eukaryotes, multicellular, autotrophic, cell wall containing cellulose
• Animalia – Eukaryotes, multicellular, heterotrophic, no cell wall
Kingdom - Eubacteria• Common name: Bacteria• Unicellular prokaryotes• Peptidogylcan in cell wall• Ecologically diverse • Basic shapes are cocci,
bacilli, spirilla• Reproduce both sexually and
asexuallyBacillus anthracis(spores can live in
soil for years)
Streptococcus mutans
(can cause endocarditis and
dental caries)
Kingdom - Archaebacteria• Cell wall does not contain
peptidogylcan• Cell membrane contains unusual
lipids not found in other organisms• Live in extreme environments
(devoid of oxygen):– volcanic hot springs– brine pools– black organic mud
Archaeafirst detected in
extreme environments,
such as volcanic hot springs.
Kingdom Protista• A classification problem – consists of
organisms that cannot be classified as animals, plants, or fungi
• Most unicellular, some colonial and some multicellular
• Autotrophic and heterotrophic• Some move with flagella,
pseudopods or cilia• Animal-like, plant-like and fungus-
like groups• Reproduce by mitosis and meiosis
Entamoeba histolytica
Kingdom Fungi• Most feed on dead, decaying
organic matter by secreting digestive enzymes into their food source then absorbing it into their bodies
• Cell walls of chitin• Most multicellular; some
unicellular• Heterotrophic
Boletus zelleri(Edible, but often infected with fly
larvae)
Epidermophyton floccosum
(one of the causes of
athlete's foot)
Kingdom Plantae• Multicellular• Nonmotile – cannot
move from place to place
• Cell wall with cellulose• Mostly photosynthetic
autotrophs
Sunflowers in Fargo, North
Dakota
Ginkgo bilobaGinkgos are often very long-lived.
Some specimens are thought to be more than 3,500
years old.
Kingdom Animalia• Multicellular• Heterotrophic• No cell walls or
chloroplasts• Incredible diversity
Chambered
Nautilus
Colony of sponges
Hymenoptera Dialictus zephrum
Txodes scapularisDeer tick
Hierarchical Systemof Classification
Domain
KingdomPhylum
ClassOrder
FamilyGenus
Species• From general to more specifi
c
How Many Kingdoms?
6Kingdoms
•Activity: What am I?
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