Classification System Notes
History of Classification
322-384 BC: Aristotle—Greek philosopher, one of the first to try to classify living things
-
grouped all living things as either plants or animals
- Plants—divided into trees, shrubs, and herbs
-
Animals—divided as those in water, on land, or could fly
-
problems:
-
some could fit more than one category
- (frogs are on land and in water);
-
some in the same category were not closely related
- (fish, lobster live in water)
-
some could fit more than one category
-
problems:
1700s: Carl von Linne (or Carolius Linnaeus)—Swedish botanist (studied plants)
- saw problems with Aristotle’s and tried to fix it
-
still classified everything as plant or animal
- very little know about microscopic organisms yet
-
system had 5 taxonomic levels, with plants and animals as 2 kingdoms of life
- gave everything a two-word name (including himself)
Binomial Nomenclature—process of assigning a 2 word name to all living things
- (bi = 2; nomial = name; nomen = name; cloture = system à “2 name naming system”)
Scientific Names
- Latin names used so scientists can communicate worldwide and be understood
-
don’t need to learn multiple names for the same organism
- Example: Felis concolor = cougar, puma, mountain lion, catamount, panther
- scientific name is composed of a genus (first) and species name (second)
Genus –group of several species that are closely related (2 with same genus name are closely related)
Species name—descriptive, so 2 can have the same species name and not be related
Writing scientific names
- Genus is first, with the first letter capitalized (may be abbreviated to one letter)
- species is second, with the first letter lowercase
- entire name is underlined or italicized
Homo sapiens or H. sapiens
Current Classification system
- based on Linnaeus’ system; works because can be changed as needed
- grown to include 8 taxonomic levels, including 3 domains and 6 kingdoms:
Levels | Examples |
Domain Kingdom Phylum Class Order Family Genus Species |
Eukarya Animalia Chordata (has backbone) Mammalia (gives milk) Primates (collar bones, grasping fingers) Hominids (flat face, 3D vision) Homo (upright, large brain) Sapiens (high forehead, thin skull) |
Can be difficult to tell differences by sight alone...