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Classification Unit
Early Classification
- taxonomy = the branch of biology that names and groups
organisms according to characteristics
- Aristotle – first to group living things (2,000 years ago)
- grouped them into plants and animals
- Linneaus – devised a system of grouping organisms into
hierarchical groups
- for the most part he used an animal’s morphology
Levels of Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Largest
Smallest
**In plants, division replaces phylum
Binomial Nomenclature
= system of two part names
- scientific name of an organism has two parts
- 1st part is the genus name
- 2nd part is the species name
examples: Homo sapiens, Tamias striatus
- rules for writing names:
1) Genus name is always capitalized, species name is not
2) Both are always underlined or in italics
- written in the Language of Latin – this allows universal
identification
Modern Classification
- Systematics = organizes living things in the context of evolution
- uses several forms of evidence
1) Fossil Record – provides a framework
2) Morphology
3) Embryological Patterns of Development
4) Chromosomes/Macromolecules
- amino acid sequences, DNA, chromosomes
- Cladogram = an ancestry diagram based on derived characters
- derived character = a feature that apparently evolved only
within a group under consideration
The Five Kingdoms
1) Bacteria
- unicellular prokaryotes
- can be divided into two groups
1) Archaebacteria
- live in harsh environments
- probably the first living things on Earth
2) Eubacteria
- the bacteria that affect your life
- very short life spans
2) Protists
- unicellular or multicellular, photosynthetic or not
- examples: Euglena, amoebas
3) Fungi
- multicellular eukaryotes
- absorb nutrients
- examples: mushrooms, mildews, molds
4) Plants
- multicellular eukaryotes
- autotrophic, photosynthetic
5) Animals
- multicellular, eukaryotes
- most have symmetry and most can move