Biology: The Science of Life

Biology is the study of life forms and living processes, and features a diverse range of organisms. Understanding the difference between inanimate matter and living organisms was a challenge for early humans, who often deified natural elements and animals.

Key Historical Advances

• Systematic description of life forms led to identification, nomenclature, and classification.
• Recognition of similarities among living organisms prompted cultural movements for biodiversity conservation.

Ernst Mayr (1904-2004)

• Regarded as the 'Darwin of the 20th century'.
• His work focused on ornithology, taxonomy, zoogeography, evolution, systematics, and the philosophy of biology.
• Known for defining the biological species concept.
• Recipient of the Balzan Prize, International Prize for Biology, and the Crafoord Prize.

Diversity in the Living World

The Living World

• The living world includes a vast variety of organisms from different habitats.
• Each type of organism is called a species; known species range between 1.7-1.8 million.

Importance of Nomenclature

• Local names vary, leading to the need for standardized naming, or nomenclature.
• Scientific names are based on principles set by international codes for both plants (ICBN) and animals (ICZN).
• Names follow binomial nomenclature, consisting of a genus name and a specific epithet (e.g., Mangifera indica).

Classification and Taxonomy

• Classification is grouping organisms based on observable features.
• Taxonomy involves characterisation, identification, classification, and nomenclature.
• Systematics includes evolutionary relationships.

Taxonomic Hierarchy

• Classification categories are known as taxa, which include kingdom, phylum/division, class, order, family, genus, and species.
• The hierarchy is based on shared characteristics, starting from species to kingdom.

Key Taxonomic Categories

1. Species: Group of individuals with fundamental similarities.
2. Genus: Group of related species.
3. Family: Group of related genera.
4. Order: Assembly of families sharing characteristics.
5. Class: Includes related orders.
6. Phylum/Division: Comprises classes (animal phyla and plant divisions differ).
7. Kingdom: Highest taxonomic category.

Summary

• The living world is diverse, facilitating the study of organisms' identification, nomenclature, and classification.
• Taxonomy provides a framework for understanding biodiversity, crucial for agriculture, forestry, and industry.

Exercises

1. Importance of classifying living organisms.
2. Reasons for changes in classification systems.
3. Criteria for classifying known individuals.
4. Insights from identifying individuals and populations.
5. Correctly writing scientific names.
6. Defining taxon with examples.
7. Identifying the sequence of taxonomic categories.
8. Understanding the concept of species in various contexts.
9. Definitions of key taxonomic terms.
10. Example-based illustration of taxonomic hierarchy.