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Organizing Life’s Diversity
Unit 5
Chapter 17
What is classification?
the grouping of objects or information based on similarities
This helps biologists understand how organisms are related to each other.
This is useful in agriculture, forestry, biochemistry, and medicine (to name a few fields).
Taxonomists study taxonomy.
the branch of biology that groups and names organisms based on studies of their different characteristics
Click on image to play video.
Aristotelian classification
Life
Plant Animal
Herb Shrub Tree Aristotle grouped organisms based on appearance and abilities.
Carolus Linnaeus: 1707-1778
Swedish botanist Created modern
classification system based on physical and structural similarities
Modern taxonomists have altered the Linnaean system to reflect evolutionary relationships.
Binomial nomenclature
two-word naming system to identify organism Genus: group of related species
always capitalized Specific epithetic: particular characteristic
always lower case
Ex: Homo sapiens
Genus specific epithet
When writing the scientific name which is Latin, one must italicize when typing or underline when handwriting.
Common names
Many people refer to organisms by common names rather than scientific names.
Be careful that common names do not always reflect the biology of the organism.
Scientific name: Fragaria ananassa
Common name: strawberry
Dichotomous key: system to identify organisms and their scientific names A key is made up of sets of numbered
statements. Each set deals with a single characteristic of
an organism, such as leaf shape or arrangement.
How living things are classified
Taxon: a group of organisms (taxa, pl.)
These groups (taxa) can be very broad or very specific.
The taxonomic levels from most broad to most specific: kingdom, phylum, class, order, family, genus, species
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Eukarya
Animalia
Chordata
Mammalia
Carnivora
Felidae
Lynx
Lynx rufus
Lynx canadensis
Bobcat Lynx
Taxonomic levels
Comparing related animals
Lynx rufus, lynx
Panthera concolor, mountain lion
Lynx canadensis, bobcat
Which two are more related? How do you know?
Mountain lion
BobcatLynx
What determines evolutionary relationship? Anatomy and physiology
Common structures imply a common ancestor. Breeding and behavior patterns Geographic distribution DNA and biochemistry
DNA comparisons between these plants show almost no difference.
Phylogeny: Studying the evolutionary histories and relationships of organisms
Cladistics: a phylogenic study that assumes probabl groups of organisms diverged and evolved
Theropods
Allosaurus
Sinornis
Velociraptor
Archaeopteryx
Light bones3-toed foot;
wishboneDown
feathers
Feathers withshaft, veins,and barbs
Flight feathers;arms as long
as legs
Fan model to indicate phylogeny
Modern six-kingdom classification
Archaebacteria: prokaryotic Eubacteria: prokaryotic Protists: eukaryotic Fungi: eukaryotic Plants: eukaryotic Animals: eukaryotic
Archaebacteria overview
Most live in extreme environments such as swamps, deep-ocean hydrothermal vents, and seawater evaporating ponds.
Most do not use oxygen to respire.
Eubacteria overview
very strong cell walls
a less complex genetic makeup than found in archaebacteria or eukaryotes
diverse habitat
Protists: A diverse groupProtists: A diverse group
• Kingdom Protista contains diverse species that share some characteristics.
• A protist is a eukaryote that.
Cilia
Oral groove
Gullet
Micronucleus and macronucleus
Contractile vacuole
Anal pore
A Paramecium
Protist overview
lacks complex organ systems
lives in moist environments diverse metabolism
Fungi overview
Decomposes matter by absorbing materials
Multicellular or unicellular
Plant overview
Multicellular Photosynthetic:
produce oxygen Immobile Cell walls
Animal overview
Multicellular Mostly mobile Lack cell walls Diverse habitats
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