Diversity in Living Organisms: Class 9 Study Guide
Millions of kinds of living things exist. Classification groups them by features so we can study them.
Scientists sort living things by similarities and differences. The five kingdom system divides life into Monera (bacteria), Protista (single-celled organisms with a nucleus), Fungi, Plantae and Animalia.
Features used include the kind of cell (with or without a nucleus), whether the body is one cell or many, how the organism gets food, and body design.
Levels of classification
From the largest group to the smallest the levels are kingdom, phylum (division in plants), class, order, family, genus and species. A species is a group of organisms that can breed together and produce offspring that can in turn breed.
| Kingdom | Examples | Key features |
|---|---|---|
| Monera | Bacteria | No nucleus, mostly single-celled |
| Protista | Amoeba, Paramecium | Single-celled with a nucleus |
| Fungi | Yeast, mushrooms | Cannot make food; feed on dead matter |
| Plantae | Rose, mango | Many cells, make food by photosynthesis |
| Animalia | Fish, birds, humans | Many cells, no cell wall, feed on others |
Naming living things
Carolus Linnaeus introduced the binomial system: each species has two names, the genus then the species, written in italics with a capital first letter for the genus. A human is Homo sapiens and a tiger is Panthera tigris. These names are the same all over the world, unlike common names that change from language to language.
Worked examples and common mistakes
Example: Which kingdom has organisms with no nucleus? Monera. Example: Which is the largest group, class or kingdom? Kingdom. Common mistakes: thinking that a virus belongs to one of the five kingdoms, and writing the species name with a capital letter.
Check your understanding: model answers
1. Monera, Protista, Fungi, Plantae, Animalia. 2. A group that can breed together to produce fertile offspring. 3. They are the same everywhere.
✨ Key Takeaways
- Living things are classified by shared features.
- There are five kingdoms.
- The levels run from kingdom down to species.
- Each species has a two-part scientific name.
💬 Questions for Discussion & Reflection
- Name the five kingdoms.
- What is a species?
- Why are scientific names useful?