Classification of Species

Traditional Classification

Historical Approach:
- Based on appearance.
- Example: Black bear, brown bear, polar bear.
- Issues: Different names globally for the same species (e.g., Grizzly bear).

Limited Information:
- Simple names don't convey species relationships.
- Example: Grizzly bears, koala bears, and panda bears aren't closely related.

Proposed by Carl Linnaeus (1700s):
- Group species by characteristics and bone structures.
- Classification hierarchy: Kingdom, Phylum, Class, Order, Family, Genus, Species.
- Names in Latin for universal understanding.
Binomial Naming System:
- Combines genus and species: e.g., Homo sapiens for humans.
- Genus name capitalized, species name lowercase, both italicized.

Introduction of Microscopic Techniques:
- Improved understanding of internal structures.
- New models combined with the Linnaean system.
Three Domain System by Carl Woese (1990s):
- Based on RNA sequence analysis.
- Domains:
  - Eukaryota: Organisms with eukaryotic cells (plants, fungi, protists, animals).
  - Bacteria: Single-celled prokaryotic organisms.
  - Archaea: Different prokaryotic cells often found in extreme conditions.

Purpose:
- Show evolutionary relationships and common ancestors.
- Example: Birds are more closely related to T-Rex than bats.
Interpretation:
- Lines splitting indicate a common ancestor splitting into two species.
- Different forms but convey the same information.

Methodology:
- Comparing structures and DNA of living species and fossil records.

Mnemonic Example:
- "Dear Kate, Please Come Over For Great Spaghetti" for Domain, Kingdom, Phylum, etc.

Classifying Organisms:
- The classification system evolved over time and combined old and new methods.
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