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 When writing the scientific name which is Latin, one must italicize when typing or underline when handwriting. Genus specific epithet
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
Taxonomic levels Domain Eukarya Kingdom Animalia Phylum Chordata Class Mammalia Order Carnivora Family Felidae Genus Lynx Species Lynx rufus Lynx canadensis Bobcat Lynx
Comparing related animals Lynx Bobcat Lynx rufus, lynx Panthera concolor, mountain lion Lynx canadensis, bobcat Which two are more related? How do you know? Mountain lion
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 Allosaurus Velociraptor Archaeopteryx Sinornis Theropods Feathers with shaft, veins, and barbs Flight feathers; arms as long as legs 3-toed foot; wishbone Down feathers Light bones
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
Section 17.2 Summary – pages 450-459 A Paramecium Protists: A diverse group Anal pore Cilia Kingdom Protista contains diverse species that share some characteristics. Oral groove A protist is a eukaryote that. Gullet Contractile vacuole Micronucleus and macronucleus Section 17.2 Summary – pages 450-459
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