What are the main features of living organisms according to the Cambridge IGCSE Biology syllabus?

The Cambridge IGCSE Biology syllabus outlines seven main features of living organisms: movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition. These characteristics help distinguish living organisms from non-living things.

How do the features of organisms help in their classification?

The features of organisms, such as their physical structure, mode of nutrition, and reproductive methods, are crucial for classification. These characteristics allow biologists to group organisms into categories like kingdoms, phyla, and species, facilitating the study of biodiversity and evolutionary relationships.

Why is movement considered a feature of living organisms?

Movement is considered a feature of living organisms because it is essential for survival. It allows organisms to find food, escape predators, and reproduce. While animals move their entire bodies, plants exhibit movement through growth and response to stimuli, such as light and gravity.

What role does respiration play in the features of organisms?

Respiration is a vital feature of organisms as it involves the biochemical process of releasing energy from food. This energy is necessary for all other life processes, including growth, movement, and reproduction. Both aerobic and anaerobic respiration are crucial for different organisms.

How do sensitivity and response to stimuli define living organisms?

Sensitivity, or the ability to respond to stimuli, is a defining feature of living organisms. It enables them to detect changes in their environment and react appropriately, ensuring survival. For example, plants grow towards light, and animals may flee from danger, showcasing their responsiveness.

Why is "Saying bacteria have NO cell walls because they're prokaryotic." a common mistake in Features of Organisms?

Why it happens: Students conflate 'prokaryote' with 'simple cell with nothing extra'. How to avoid it: Bacteria DO have cell walls (made of PEPTIDOGLYCAN, a different material from plant cellulose walls). What makes them prokaryotic is the absence of a NUCLEUS.

Why is "Mixing up amphibians and reptiles." a common mistake in Features of Organisms?

Why it happens: Both are scaly-looking and lay eggs. How to avoid it: Amphibians: WET skin, soft eggs in WATER, gills as juveniles. Reptiles: DRY scaly skin, leathery-shelled eggs on LAND, lungs from birth.

Why is "Calling spiders 'insects'." a common mistake in Features of Organisms?

Why it happens: Both are small invertebrates. How to avoid it: Spiders are ARACHNIDS (8 legs, 2 body parts). Insects have 6 legs and 3 body parts (head, thorax, abdomen).

Why is "Calling mushrooms 'plants'." a common mistake in Features of Organisms?

Why it happens: They look like plants and grow rooted to the ground. How to avoid it: Fungi are their OWN kingdom. They have no chlorophyll, don't photosynthesise, and absorb nutrients from dead matter (saprotrophic). DNA shows fungi are more closely related to ANIMALS than to plants.

Characteristics and Classification of Living OrganismsCambridge IGCSE Biology (0610)

Features of Organisms

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Features of Organisms — Cambridge IGCSE 0610 Biology Extended (2026)

Distinguishing features of the five kingdoms, the major animal phyla and arthropod classes, plus the four classes of vertebrate. Cambridge wants both structural AND nutritional features.

What you’ll learn

Mapped to the Cambridge IGCSE 0610 syllabus (2026-2028).

1.3 — State features of the five kingdoms.
1.3 — Identify common phyla / classes from features.
1.3 — Distinguish vertebrates and invertebrates.
1.3 — Identify arthropod sub-groups.

The five kingdoms

Animal, Plant, Fungus, Prokaryote, Protoctist — distinguished by cell features and nutrition.

Animals.

Multicellular EUKARYOTES (cells with nuclei).
Cells have NO cell walls — flexible.
HETEROTROPHIC: feed by eating other organisms.
Often capable of complex movement.
Examples: insects, fish, mammals, worms, jellyfish.

Plants.

Multicellular EUKARYOTES.
Cells have CELLULOSE cell walls (rigid).
Cells contain CHLOROPLASTS for photosynthesis.
AUTOTROPHIC: make own food via photosynthesis.
Often have roots, stems, leaves.
Examples: oak trees, grass, ferns, mosses.

Fungi.

USUALLY multicellular (yeasts are single-celled).
Cells have walls of CHITIN (different from plants' cellulose).
Body usually a network of thread-like HYPHAE forming a mycelium.
SAPROTROPHIC: secrete enzymes onto dead matter and absorb nutrients (or PARASITIC).
Examples: mushrooms, yeast, mould, athlete's foot fungus.

Prokaryotes (Bacteria).

SINGLE-CELLED.
NO NUCLEUS — DNA loose in cytoplasm.
Cells have walls (peptidoglycan).
Variable nutrition: many heterotrophic, some photosynthetic.
Examples: E. coli, Bacillus, blue-green algae (cyanobacteria).

Protoctists.

Eukaryotic but usually SINGLE-CELLED, or simple multicellular (e.g. seaweed).
'Catch-all' kingdom for eukaryotes that don't fit animal/plant/fungus.
Variable nutrition.
Examples: Amoeba, Paramecium, Plasmodium (malaria parasite), Euglena, algae.

Cambridge tip. Distinguishing features asked include: cell type (eukaryotic vs prokaryotic), cell walls (yes/no, what material), unicellular vs multicellular, nutrition type. Nail TWO features per kingdom.

Animal: multicellular, no walls, heterotrophic.
Plant: cellulose walls, chloroplasts, autotrophic.
Fungus: chitin walls, saprotrophic.
Prokaryote: NO nucleus, peptidoglycan walls.
Protoctist: simple eukaryotes; variable nutrition.

Vertebrate classes

Five classes: fish, amphibian, reptile, bird, mammal. Distinguished by skin, eggs, breathing, body temperature.

All vertebrates have a BACKBONE (vertebral column). The five classes:

Fish.

Wet, scaly skin.
Lay eggs in water.
Breathe through GILLS.
Cold-blooded (ectothermic).
Live in water.

Amphibians (e.g. frogs, toads, newts).

Wet, smooth skin.
Lay soft eggs in water.
Breathe through GILLS as larvae (tadpoles), LUNGS as adults.
Cold-blooded.
Need water to reproduce; can live in water and on land.

Reptiles (e.g. snakes, lizards, turtles).

DRY, scaly skin.
Lay eggs with leathery shells on LAND.
Breathe through LUNGS from birth.
Cold-blooded (ectothermic).

Birds.

Feathers (key feature!).
Hard-shelled eggs on land.
Lungs.
Warm-blooded (endothermic).
Beaks, no teeth.
Most fly.

Mammals (e.g. cats, humans, bats, whales).

HAIR/FUR.
Most give birth to live young (some monotremes lay eggs — platypus, echidna).
Females produce MILK from MAMMARY GLANDS.
Lungs.
Warm-blooded.

Worked qualitative. A penguin: feathers (bird), warm-blooded, lays eggs. So it's a BIRD even though it can't fly. Flying isn't required to be a bird.

Worked qualitative. A whale: warm-blooded, lives in water, has lungs, gives birth to live young, drinks milk. → MAMMAL. Lives in the sea but isn't a fish.

Fish: gills, water, scaly, cold-blooded.
Amphibian: wet skin, gills→lungs, eggs in water.
Reptile: dry scaly skin, eggs on land, lungs.
Bird: feathers, hard eggs, warm-blooded.
Mammal: hair/fur, milk, warm-blooded, mostly live young.

Arthropods — invertebrates with exoskeleton

Four big classes: insect, arachnid, crustacean, myriapod.

Arthropods have:

A hard EXOSKELETON (made of chitin).
JOINTED LEGS.
Segmented body.

Four main classes.

Insects.

3 body parts: head, thorax, abdomen.
6 legs (3 pairs on thorax).
Usually wings (1 or 2 pairs).
1 pair of antennae.
Examples: ants, bees, butterflies, beetles, flies.

Arachnids.

2 body parts: cephalothorax + abdomen.
8 legs.
NO antennae, NO wings.
Examples: spiders, scorpions, mites, ticks.

Crustaceans.

2 body parts: cephalothorax + abdomen.
10+ legs.
2 pairs of antennae.
Often live in water.
Examples: crabs, lobsters, prawns, woodlice.

Myriapods (centipedes, millipedes).

Many body segments.
1 (centipede) or 2 (millipede) pairs of legs PER SEGMENT.
1 pair of antennae.

Cambridge identification trick. Count LEGS first.

6 legs: insect.
8 legs: arachnid.
10+ legs (and water-dwelling): crustacean.
Many legs along long body: myriapod.

Worked qualitative. A garden spider has 8 legs and a body in 2 parts. Class: ARACHNID. NOT an insect.

Insect: 6 legs, 3 body parts, often wings, 1 pair antennae.
Arachnid: 8 legs, 2 body parts, no antennae, no wings.
Crustacean: 10+ legs, 2 antennae, often aquatic.
Myriapod: many legs along segmented body.

Other invertebrate phyla (briefly)

Annelids (worms), molluscs (snails, octopuses), nematodes — common features.

Annelids (segmented worms).

Long, soft body in many ring-like segments.
No legs.
Examples: earthworm, leech.

Molluscs.

Soft body, often with a shell (or vestigial shell).
Many have a muscular foot.
Examples: snails, slugs, octopus, squid, oysters.

Nematodes (roundworms).

Cylindrical, unsegmented body.
Often parasitic.
Examples: hookworms, ascaris, Caenorhabditis elegans (research).

Cnidarians (jellyfish, hydra, coral).

Radially symmetric, often with stinging cells.
Soft, jelly-like body.

Echinoderms (starfish, sea urchins).

5-fold radial symmetry.
Spiny skin.
Marine.

Cambridge tip. Cambridge IGCSE doesn't quiz every invertebrate phylum in depth — focus on arthropods and the few you might encounter in food chains or environment questions.

Annelid: segmented worm.
Mollusc: soft body, often shell, muscular foot.
Nematode: roundworm, often parasitic.
Cnidarian: jellyfish/hydra, radial symmetry.
Echinoderm: starfish, 5-fold symmetry.

How it’s examined

Features of organisms appears every Paper 4 (4-6 marks): identify a kingdom, vertebrate class, or arthropod class from features. Examiner reports flag students saying 'bacteria have no cell walls' (they do — peptidoglycan), and confusing amphibians with reptiles.

Sources: Cambridge IGCSE Biology 0610 syllabus 2026-2028 (1.3); 0610/22 May/Jun 2024 — Q3 (five kingdoms, arthropods); 0610 Examiner Reports 2022-2024. Last reviewed 2026-05-07.

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Step-by-step worked examples — Features of Organisms

Step-by-step solutions to past-paper-style questions on features of organisms, written exactly the way a tutor would explain them at the board.

1Distinguishing features of the five kingdoms
Core• five kingdoms
Question
Give one structural and one nutritional feature for each of the five kingdoms.
Step-by-step solution
1. Step 1
  Animal: multicellular eukaryote; cells WITHOUT cell walls. NUTRITION: heterotrophic — eat other organisms.
2. Step 2
  Plant: multicellular eukaryote; cells with CELLULOSE cell walls and CHLOROPLASTS. NUTRITION: autotrophic — photosynthesise.
3. Step 3
  Fungus: usually multicellular; cells with cell walls (chitin); often hyphal threads. NUTRITION: saprotrophic (decompose dead matter) or parasitic.
4. Step 4
  Prokaryote (bacteria): single-celled, NO nucleus, cells DO have walls (peptidoglycan). Nutrition: variable — many feed on organic matter, some autotrophic.
5. Step 5
  Protoctist: usually single-celled eukaryotes (e.g. amoeba, paramecium); some multicellular (algae). Nutrition: variable — some autotrophic (algae), some heterotrophic (amoeba).
Answer
Animal/Plant: multicellular eukaryotes. Fungi: walls of chitin, saprotrophic. Prokaryotes: NO nucleus. Protoctists: simple eukaryotes (single-celled or simple multicellular).
2Identify a vertebrate class from features
Core• vertebrates
Question
An animal has wet scaly skin, lays soft eggs in water, and breathes through gills as a juvenile and lungs as an adult. Which vertebrate class is it?
Step-by-step solution
1. Step 1
  Wet scaly skin is shared by amphibians and fish.
2. Step 2
  Soft eggs in water (no shell) is amphibian (or fish).
3. Step 3
  Switch from gills to lungs across life stages: AMPHIBIAN.
Answer
Amphibian (e.g. frog).
3Identify the arthropod subgroup
Core• Adapted from 0610/22 May/Jun 2024 Q3• arthropods
Question
An invertebrate has 8 legs and 2 body parts (cephalothorax + abdomen). Which arthropod class is it?
Step-by-step solution
1. Step 1
  8 legs rules out insects (6) and crustaceans (variable, 10+).
2. Step 2
  8 legs + 2 body parts = ARACHNID (spiders, scorpions, mites).
Answer
Arachnid.

Key Definitions and Keywords — Features of Organisms

Definitions to memorise and the exact keywords mark schemes credit for features of organisms answers — sharpened from recent examiner reports for the 2026 0610 sitting.

Eukaryote
An organism whose cells contain a nucleus and membrane-bound organelles. Includes animals, plants, fungi, protoctists.
Prokaryote
Examiner keyword
A single-celled organism with NO nucleus and no membrane-bound organelles. DNA is free in the cytoplasm. Bacteria are prokaryotes.
Autotrophic
Examiner keyword
Making own food from inorganic raw materials, e.g. by photosynthesis. Plants and many algae are autotrophic.
Heterotrophic
Examiner keyword
Obtaining nutrients by consuming other organisms or organic material. Animals, fungi, many bacteria are heterotrophic.
Saprotrophic
A type of heterotrophic nutrition: feeding on dead and decaying organic matter by secreting enzymes that digest externally and absorbing the products. Most fungi are saprotrophic.
Vertebrate
An animal with a backbone (vertebral column).
Invertebrate
An animal without a backbone.
Arthropod
An invertebrate with a hard exoskeleton, jointed legs, and a segmented body. Includes insects, arachnids, crustaceans, myriapods.

Common Mistakes and Misconceptions — Features of Organisms

The traps other students keep falling into on features of organisms questions — taken from recent Cambridge IGCSE 0610 examiner reports and mark schemes — and how to avoid them.

✕Saying bacteria have NO cell walls because they're prokaryotic.
Why it happens
Students conflate 'prokaryote' with 'simple cell with nothing extra'.
How to avoid it
Bacteria DO have cell walls (made of PEPTIDOGLYCAN, a different material from plant cellulose walls). What makes them prokaryotic is the absence of a NUCLEUS.
✕Mixing up amphibians and reptiles.
Why it happens
Both are scaly-looking and lay eggs.
How to avoid it
Amphibians: WET skin, soft eggs in WATER, gills as juveniles. Reptiles: DRY scaly skin, leathery-shelled eggs on LAND, lungs from birth.
✕Calling spiders 'insects'.
Why it happens
Both are small invertebrates.
How to avoid it
Spiders are ARACHNIDS (8 legs, 2 body parts). Insects have 6 legs and 3 body parts (head, thorax, abdomen).
✕Calling mushrooms 'plants'.
Why it happens
They look like plants and grow rooted to the ground.
How to avoid it
Fungi are their OWN kingdom. They have no chlorophyll, don't photosynthesise, and absorb nutrients from dead matter (saprotrophic). DNA shows fungi are more closely related to ANIMALS than to plants.

Practice questions

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Past paper style quiz

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Features of Organisms — frequently asked questions

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Features of Organisms

Short Study Notes in the form of Slides

Detailed Study Notes

What you’ll learn

How it’s examined

1Distinguishing features of the five kingdoms

2Identify a vertebrate class from features

3Identify the arthropod subgroup

Eukaryote

Prokaryote

Autotrophic

Heterotrophic

Saprotrophic

Vertebrate

Invertebrate

Arthropod

✕Saying bacteria have NO cell walls because they're prokaryotic.

✕Mixing up amphibians and reptiles.

✕Calling spiders 'insects'.

✕Calling mushrooms 'plants'.

Practice questions

Past paper style quiz

Assess your understanding

Video lesson

Features of Organisms — frequently asked questions