The Living World

This chapter asks a basic question: what is living? Growth, reproduction, metabolism, cellular organisation and the ability to sense the environment are characteristic features of living organisms. Of these, metabolism, cellular organisation and consciousness are defining properties, since growth and reproduction are not shown by all living beings, such as mules or sterile worker bees. The number of species that are known and described ranges between 1.7 and 1.8 million, so organisms must be identified, named and classified scientifically. You will learn about taxonomy and systematics, and the system of binomial nomenclature given by Carolus Linnaeus. Each scientific name has a generic name and a specific epithet, written in Latin and printed in italics or underlined, as in Mangifera indica. The naming of plants follows the International Code for Botanical Nomenclature (ICBN), and of animals the International Code of Zoological Nomenclature (ICZN). The chapter then explains the taxonomic hierarchy of categories, from kingdom, phylum or division, class, order and family to genus and species, with examples like man, housefly, mango and wheat.

Detailed Worksheet: The Living World Section A - Definitions (10 marks) 1. What are the defining properties of living organisms? Why are growth and reproduction not defining properties? (2 marks) 2. What is binomial nomenclature? Who proposed it? (2 marks) 3. Define taxonomy and systematics. (2 marks) 4. What is a taxon? Give an example. (2 marks) 5. What is meant by taxonomic hierarchy? (2 marks) Section B - Calculations and Applications (15 marks) 6. Correct the following scientific names according to the rules of binomial nomenclature and state the rules used: mangifera Indica, Panthera Leo, solanum tuberosum, Homo Sapiens. (3 marks) 7. Arrange the following categories in ascending order (lowest first): class, species, kingdom, genus, order, phylum, family. How many categories are there? How do the number of common characters change as we go from species to kingdom? (3 marks) 8. About 1.75 million species have been described. If about 70% are animals and about 22% are plants (including fungi and algae), calculate the approximate number of each. What fraction of described species belongs to other groups? (3 marks) 9. Write the taxonomic categories of mango (Mangifera indica) from kingdom to species, and identify the family and order. (3 marks) 10. Write the taxonomic categories of the housefly (Musca domestica) from kingdom to species. To which class and order does it belong? (3 marks) Section C - Diagrams (10 marks) 11. Draw a diagram showing the taxonomic hierarchy as a pyramid, from kingdom to species, and indicate how the number of common characters changes. (4 marks) 12. Draw a flowchart showing the classification of the lion, tiger and leopard into one genus, family and order with the dog. (3 marks) 13. Draw a flowchart showing the classification of wheat (Triticum aestivum) from kingdom to species. (3 marks) Section D - Analysis and Higher-order Thinking (15 marks) 14. 'Metabolism is a defining feature of all living organisms without exception.' Explain this with reference to how isolated metabolic reactions outside the body behave. Why is consciousness considered a defining property? (5 marks) 15. Explain why scientific names are necessary when common names exist. Explain the rules of binomial nomenclature with examples, including how the author's name is written. (5 marks) 16. Using the examples of Panthera, Felis and Canis, explain how genus, family and order are related. How does grouping into higher categories help in studying organisms? (5 marks) Instructions: Time allowed 2 hours. Attempt all sections. Write scientific names correctly (underline when handwritten). Draw diagrams and flowcharts neatly with labels.