To study living things, animals are divided into :
Five Kingdoms (Classification based on: cell type, complexity, and mode of nutrition):
- Monera
- Protista
- Fungi
- Plants
- Animals
Plant Cell
- Cell Walls: Present (provide protection). Animals don’t have cell walls.
- Chloroplasts: Present (contain chlorophyll required for photosynthesis).
- Vacuole: Present (store water, food, and waste).
Classification of Plants
- 80% of the plant kingdom are flowering plants (Angiosperms).
- Angiosperms produce flowers and fruits (with seeds in them).
Angiosperms
Angiosperms are divided into: Monocotyledons and Dicotyledons based on the number of cotyledons (seed leaves).
| Feature | Monocotyledons (Monocots) | Dicotyledons (Dicots) |
| Cotyledons | One seed leaf | Two seed leaves |
| Leaf Veins | Narrow leaves with parallel veins | Broader leaves with net-like veins |
| Flower Petals | Have petals in multiples of 3 | Have petals in multiples of 4 or 5 |
| Examples | Onion, Rice, Maize seed, Sweet pea | Chickpea |
Animal Cells
Each type of cell performs a different function:
- Nerve cells: Receive messages in the brain.
- Blood cells: Carry oxygen.
Main Parts of an Animal Cell
The main parts are the Organelles : Nucleus, Cytoplasm, Cell membrane, and Vacuole.
| Part | Function |
| Nucleus | The control center of the cell. |
| Controls cell growth. | |
| Controls cell reproduction. | |
| Cytoplasm | Helps to move materials around the cell. |
| Helps to dissolve waste. | |
| Vacuole | A space in the cytoplasm. |
| Contains air, liquid, or food. | |
| Cell Membrane | Acts as a barrier to the outside world. |
| Lets things in and out of the cell. | |
| Stops dangerous things from getting in. |
Animal Classification
Animals are divided into groups based on their structure.
Animals are categorized as Vertebrates or Invertebrates.
| Feature | Vertebrates | Invertebrates |
| Backbone | Have a backbone (Spinal column) | Don’t have a backbone |
| Percentage | Less than 5% of all animals | More than 95% of all animals |
| Skeleton | Don’t have an external skeleton | May have a hard external covering (shell) or no hard covering |
| Eyes | Do not have compound eyes | Have compound eyes |
| Size | Comparatively large | Comparatively smaller |
Animal Sub-Classification
Animals are divided into two main groups: Vertebrates and Invertebrates.
1. Vertebrates
Vertebrates are further divided into five classes:
- Birds
- Fish
- Amphibians
- Reptiles
- Mammals
2. Invertebrates
Invertebrates are further divided into major phyla, including:
- Arthropods
- Echinoderms
- Cnidarians
- Sponges
- Molluscs
- Worms
Vertebrates: Birds vs. Fish
| Birds | Fish |
| Warm-blooded | Cold-blooded |
| Lay eggs | Lay eggs |
| Have feathers & wings | Have fins |
| Breathe through lungs | Breathe through gills (Take water in by gill) |
| Have scales on legs and feet | Have scales on the body |
| Have a beak with no teeth | Live in water |
| Possess a furcula (wishbone) to protect the chest | |
| Flightless examples: ostrich, penguin, kiwi, cassowaries | |
| Hummingbird flies backward |
Fun Fact : (e.g., Sea-horse swims upright)
1. Amphibians
- Have thin skin.
- Begin life in water; live on land as adults.
- Adult females return to water for laying eggs.
- Don’t have scales or claws.
- Cold-blooded.
- Fact: Frogs and salamanders can jump 10x the length of their body.
2. Reptiles
- Cold-blooded.
- Lay eggs (with a leathery, waterproof shell).
- Typically have four legs (though snakes are limbless).
- Have scales instead of hair/fur.
- Breathe with lungs.
- Have external ear openings.
- Fact: Dinosaurs, which were the dominant vertebrates, ruled Earth 100 million years ago.
3. Mammals
- Warm-blooded (keep a constant temperature; able to be active in any temperature).
- Females feed their young.
- Have hair or fur.
Here are the text-based infograms from the final two images, detailing the Invertebrate phyla:
Invertebrates: Arthropods, Echinoderms, Cnidarians, and Sponges
1. Arthropods
- Three-quarters of all animals are arthropods.
- They are a major source of food for other animals.
- Some plants also eat them.
- Groups: Insects, Arachnids (Spiders, Scorpions), Crustaceans (Crabs, Lobsters), Centipedes, Millipedes.
- Insects are defined by:
- One million species identified.
- Three-section body (head, thorax, abdomen).
- One pair of antennae.
- Three pairs of legs.
- Fact: Mosquitoes kill more humans than any other animal.
- Fact: A salamander can regrow a lost tail.
2. Echinoderms
- Live in water (Starfish, Sea urchin).
- Have a star-like shape.
- They are marine animals.
- Have a unique water vascular system which:
- Allows the transport of food/water.
- Helps in movement.
3. Cnidarians
- Live in water.
- Have a bag-like body with tentacles.
- Examples: Jellyfish and Coral.
- Fact: The box jellyfish is considered one of the deadliest jellyfish.
4. Sponges
- They are the simplest form of animals.
- Don’t have nervous or muscular systems.
- Cannot move on their own.
- Cannot hunt for food; they live on the water flow.
- Live on the seafloor.
1. Molluscs
- Some live on land; most live in shallow water.
- The largest group of Invertebrates after Arthropods.
- Body divided into: head, body cavity, muscular foot, and mantle.
- The head & foot region is easily observable.
- Examples: Oysters, Snails, Octopuses.
2. Worms
- Types: Segmented worms, Flat worms, and Round worms.
- Have a soft, long, tube-like body.
- Some are divided into segments.
- Don’t have arms or legs.
- Some can detect chemical changes and have light sensing abilities.
- Roles: Some are parasites, decomposers, or predators.
1. Which structure is present in a Plant Cell but is **absent** in an Animal Cell, providing protection to the cell?
A. Vacuole
B. Cell Membrane
C. Cell Wall
D. Chloroplasts
2. Which characteristic correctly describes the leaves of **Monocotyledons**?
A. Leaves with petals in multiples of 4 or 5.
B. Leaves that contain two seed leaves (cotyledons).
C. Narrow leaves with parallel veins.
D. Broader leaves with net-like veins.
3. Which group of living organisms is **not** one of the Five Kingdoms mentioned for classification?
A. Protista
B. Fungi
C. Viruses
D. Monera
4. The primary defining feature used to categorize an animal as either a Vertebrate or an Invertebrate is the presence or absence of a:
A. Hard external covering (shell)
B. Lungs for breathing
C. Compound eye
D. Spinal column (Backbone)
5. Which description is characteristic of **Reptiles**?
A. Are warm-blooded and have feathers and wings.
B. Have thin skin and begin life in water.
C. Breathe through gills and have scales on the body.
D. Lay eggs with a leathery, waterproof shell.
6. What two features are essential characteristics of **Mammals**?
A. Have fins and breathe through gills.
B. Warm-blooded and females feed their young.
C. Have external ear openings and four legs.
D. Cold-blooded and lay eggs with scales.
8. After Arthropods, which is the **largest group** of Invertebrates, whose members include snails, oysters, and octopuses?
A. Worms
B. Cnidarians
C. Molluscs
D. Echinoderms
9. Which cellular organelle is correctly identified as the **control center** that regulates the cell’s growth and reproduction?
A. Cytoplasm
B. Nucleus
C. Vacuole
D. Cell Membrane
10. Which group of invertebrates is described as the **simplest form of animals**, lacking nervous and muscular systems, and unable to move or hunt for food?
A. Worms
B. Echinoderms
C. Cnidarians
D. Sponges
Answer Key
| Question Number | Correct Answer |
| 1 | Cell Wall |
| 2 | Narrow leaves with parallel veins. |
| 3 | Viruses |
| 4 | Spinal column (Backbone) |
| 5 | Lay eggs with a leathery, waterproof shell. |
| 6 | Warm-blooded and females feed their young. |
| 7 | Three sections (Head, Thorax, Abdomen). |
| 8 | Molluscs |
| 9 | Nucleus |
| 10 | Sponges |