Summary
Classification in biology involves organizing living organisms into groups based on shared characteristics. The three domains of life are Archaea, Bacteria, and Eukarya.
- Species — a group of organisms capable of interbreeding and producing fertile offspring.
Example: Humans belong to the species Homo sapiens. - Morphological species concept — groups organisms based on physical similarities.
Example: Birds with similar beak shapes may be classified together. - Ecological species concept — defines species based on their ecological niche.
Example: Different species of fish occupying distinct parts of a coral reef. - Binomial system — a two-part scientific naming system for species.
Example: The binomial name for humans is Homo sapiens. - Taxonomy — the practice of classifying organisms into a hierarchical system.
Example: Kingdom, phylum, class, order, family, genus, species. - Viruses — acellular entities classified based on their nucleic acid type.
Example: DNA or RNA, single-stranded or double-stranded.
Exam Tips
Key Definitions to Remember
- Species
- Morphological species concept
- Ecological species concept
- Binomial system
- Taxonomy
Common Confusions
- Differences between Archaea and Bacteria
- Classification of viruses outside the three domains
Typical Exam Questions
- What is a species? A group of organisms that can interbreed and produce fertile offspring.
- How are viruses classified? Based on the type of nucleic acid (DNA or RNA) and whether it is single-stranded or double-stranded.
- What are the three domains of life? Archaea, Bacteria, and Eukarya.
What Examiners Usually Test
- Understanding of the hierarchical classification system
- Differences between prokaryotic and eukaryotic cells
- Characteristics of the kingdoms within the Eukarya domain
