Notes on Classification, Taxonomy, and Phylogeny

Introduction

• Lecture by Mr. Stroke on biology covering:
  • Classification
  • Taxonomy
  • Binomial nomenclature
  • Phylogenetic classification

Binomial System

• Universal naming method for organisms.
• Consists of two parts:
  • Genus: First part of the name (capitalized).
  • Species: Second part of the name (not capitalized).
• Example:
  • New Zealand Robin: Petroica australis
  • Common Robin: Erithacus rubecula
• Importance:
  • Helps understand relationship between organisms.
  • Misleading common names can be clarified by binomial names.
  • Example of closely related species: Tiger (Panthera tigris) and Jaguar (Panthera onca).

Similarity of Different Species

• Example: Camel and Llama
  • Similar features due to similar environmental conditions.
• Links to natural selection and evolution.
  • Similar alleles within gene pools provide selective advantage.

Classification Systems

• Hierarchical classification system:
  • Definition:
    1. Small groups within large groups.
    2. No overlap between groups.
• Hierarchical levels:
  • Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species
• Each group is called a taxon.
• Mnemonic for classification:
  • Dear King Philip Came Over For Good Soup.

Purpose of Classification

• Organizes millions of species, including undiscovered ones.
• Helps understand relationships and track changes (evolution, climate change, human impact).

Methods of Classification

• Originally based on visible similarities and differences.
  • Drawbacks include variability within species (e.g., dog breeds).
• Modern methods:
  1. DNA base sequence comparison.
  2. mRNA base sequence comparison.
  3. Amino acid sequence comparison.
  4. Immunological comparisons: Similarity of antigens and antibodies.

Phylogenetic Classification

• Focuses on evolutionary origins and relationships.
• Useful for studying common ancestors.
  • Example of phylogenetic trees showing evolutionary paths.
• Common ancestor of humans and chimpanzees.
• Understanding speciation and divergence over generations.

Conclusion

• Summary of classification importance and methods.
• Encouragement to like and subscribe for more biology content.