Transcript Classification of Living Things

Biology
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Scientists classify organisms and assign each
organism a universally accepted name
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To organize similar organisms
So all scientists are discussing the same
organisms (species)
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Species  population of organisms that share similar
characteristics and can breed with one another and
produce fertile offspring
 Identified 1.5 million species so far
 Estimate 2-100 million have yet to be discovered
What tools can we use to show similarities
in organisms?
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Cladistic analysis  identifies and considers
only those characteristics of organisms that are
evolutionary innovations – new characteristics
that arise as lineages evolve over time
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Cladogram – diagram that shows evolutionary
relationships among a group of organisms
Modern Evolutionary Classification
Darwin’s ideas about descent gave
rise to the study of phylogeny –
evolutionary relationships among
organisms
Evolutionary Classification – Grouping
of organisms based on evolutionary
history
Appendages
Crab
Conical Shells
Barnacle
Limpet
Crustaceans
Crab
Barnacle
Gastropod
Limpet
Molted
exoskeleton
Segmentation
CLASSIFICATION
BASED ON VISIBLE
SIMILARITIES
Tiny free-swimming larva
CLADOGRAM
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Genes of many organisms show important
similarities at a molecular level. Similarities in
DNA can be used to help determine
classification and evolutionary relationships
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Swedish botanist that developed a two-word
naming system called BINOMIAL
NOMENCLATURE
 Gives the Genus and species name, written in italics or
underlined
 Language is usually Latin
 Example:
 House cat – Felis domesticus
 Dog – Canis familaris
 Human – Homo sapien
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Domain (most inclusive, less in common)
Kingdom
Phylum
Class
Order
Family
Genus
Species (less inclusive, more in common)
Each level is called a TAXON; taxa (plural)
Grizzly bear
Black bear Giant
panda
Red fox
Abert
squirrel
KINGDOM Animalia
PHYLUM Chordata
CLASS Mammalia
ORDER Carnivora
FAMILY Ursidae
GENUS Ursus
SPECIES Ursus arctos
Coral
snake
Sea star
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Currently, all organisms are grouped into 1 of
3 domains which reflect evolutionary
relationships
1) Bacteria
 2) Archaea
 3) Eukarya
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ARCHAEA
EUKARYA
Kingdoms
BACTERIA
LUCA – last universal common ancestor
Eubacteria
Archaebacteria
Protista
Plantae
Fungi
Animalia