1.3 Features of Organisms

2026 Syllabus Objectives

  1. State the main features used to place animals and plants into the appropriate kingdoms
  2. State the main features used to place organisms into groups within the animal kingdom, limited to:
    • (a) the main groups of vertebrates: mammals, birds, reptiles, amphibians, fish
    • (b) the main groups of arthropods: myriapods, insects, arachnids, crustaceans
  3. Classify organisms using the features identified in 1.3.1 and 1.3.2
  4. State the main features used to place all organisms into one of the five kingdoms: animal, plant, fungus, prokaryote, protoctist
  5. State the main features used to place organisms into groups within the plant kingdom, limited to ferns and flowering plants (dicotyledons and monocotyledons)
  6. Classify organisms using the features identified in 1.3.4 and 1.3.5
  7. State the features of viruses, limited to a protein coat and genetic material

The Five Kingdoms 🌍

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Living organisms are classified into five major kingdoms based on their shared characteristics. These kingdoms represent the largest groups in biological classification:

  1. Animal kingdom
  2. Plant kingdom
  3. Fungus kingdom
  4. Prokaryote kingdom
  5. Protoctist kingdom

Key Term: A kingdom is one of the major groups into which all organisms are classified.

The Animal Kingdom 🐾

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Animals are usually easy to recognize because most can move actively while looking for food. Under the microscope, their cells show distinctive features.

Characteristic Features of Animals ⚡

  • Their cells have a nucleus, but no cell walls or chloroplasts
  • They feed on organic substances made by other living organisms
  • Most animals can move actively (though some, like sea anemones, stay in one place)

Key Term: Organic substances are substances whose molecules contain carbon; in biology, these are normally compounds made by living things.

The Plant Kingdom 🌱

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Plants are most familiar to us as flowering plants, which include most trees. However, there are other types like ferns and mosses that do not have flowers.

Characteristic Features of Plants 📌

  • Their cells have a nucleus and cell walls made of cellulose
  • Their cells often contain chloroplasts
  • They feed by photosynthesis
  • They may have roots, stems and leaves (but some plants do not have these organs)
  • They contain chlorophyll, a green pigment that absorbs energy from sunlight

Key Plant Structures

Plants typically have:

  • Flowers (in flowering plants)
  • Fruits (in flowering plants)
  • Stems (above ground)
  • Leaves (for photosynthesis)
  • Roots (underground for water and mineral absorption)

Key Terms:

  • Chlorophyll is a green pigment that absorbs energy from light; the energy is used to combine carbon dioxide with water to make glucose
  • Cellulose is a carbohydrate that forms long fibres and makes up the cell walls of plants

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