CLASSIFICATION OF
LIVING THINGS
There is tremendous diversity of living things. With over 1.5
million organisms identified, biologists need some way of
organizing these life forms so that they can be studied. Grouping
living things into similiar categories is called the science of
taxonomy. A scientist by the name of Carolus Linneaus created the
first, most useable classification categories.
The science of taxonomy (classification) assumes
1) there are similarities in organism types from one generation
to the next
2) all organisms share some characteristics in common, based on
their evolutionary history.
Scientists, who classify living things, use similarities and
differences from their observations to develop classification
systems. These scientists use cell structure, food source,
physical appearance, genetic make-up, fossil records and the like
to form the classification categories.
Traditionally, taxonomists (scientists who classify living
things) adopt the five kingdom classification system. These
categories include:
Kingdom |
Examples and Characteristics |
| Monera | bacteria,... simple single cells--prokaryotic cell types, may be able to photosynthesize, usually consumers / decomposers, reproduce by cell division |
| Protista | Euglena, Amoeba, Algae... usually complex single cells--eukaryotic cell types, some cells join forming colonies of cells, the junk-drawer of the classification system--cells in this Kingdom may be plantlike, animallike, funguslike, some photosynthesize, some are consumers, some parasites, reproduce by cell division and a few have complex life cycles |
| Fungi | Mushrooms, athlete's foot, morels, ringworm, yeast,...usually multicellular composed of complex cells--eukaryotic cell types, function mostly as decomposers and a few are parasites, reproduce through complex life cycles--sexually and asexually |
| Plantae | mosses, grasses, birch trees, dandelions, apple trees,...multicelluar composed of complex cells--eukaryotic cell types, many form tissues, organs, organ systems--leaf, root, stem, stamens, pistils, ovules, anthers, function as producers (photosynthesis), reproduce through complex life cycles--sexually and asexually |
| Animalia | sea anemones, sponges, jellyfish, corals, fish, sharks, clam, snails, squid, spiders, insects, mammals, reptiles, amphibians, birds,...multicellular composed of complex cells--eukaryotic cell types, many form tissues, organs, and organ systems--digestive, circulatory, excretory, reproductive systems, reproduce through complex life cycles--sexually and asexually |