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Year 8 Science — Life processes in animals

Follow food through the alimentary canal and say what each part does, tell breathing from respiration, and match an animal to the way it takes in oxygen.

Name: ________________________

Before you start

The parts of the human respiratory system, from the nostrils down.

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  1. 1. Nostrils
  2. 2. Windpipe
  3. 3. Lung
  4. 4. Rib cage
  5. 5. Diaphragm

Air comes in at the nostrils, down the windpipe, and into branches that end in tiny balloon-like sacs called alveoli inside the lungs. The rib cage guards the lungs; the dome-shaped diaphragm below them does the pulling.

  1. 1.Why is the inner lining of the small intestine covered in thousands of finger-like projections?

    • a) They make the digestive juices the small intestine needs
    • b) They increase the surface area, so nutrients are absorbed efficiently
    • c) They stop acid from the stomach reaching the intestine wall
    • d) They grip the food and stop it moving on too fast

  2. 2.Tap the part of this alimentary canal where most of the digested nutrients are absorbed into the blood.

    Write the number of the part.

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  3. 3.Put the parts of the alimentary canal in the order food passes through them, starting at the mouth.

    • Stomach
    • Small intestine
    • Large intestine
    • Rectum
    • Mouth
    • Anus
    • Oesophagus

  4. 4.Sort each animal by the part of its body that takes in oxygen.

    Groups: Breathes with lungs · Breathes with gills · Breathes through moist skin

    • Tadpole
    • Earthworm
    • Fish
    • Lion
    • Snake

  5. 5.Respiration uses oxygen to break down glucose. What comes out of it?

    • a) Oxygen, water and starch
    • b) Glucose and energy, with nothing given off
    • c) Carbon dioxide, water and energy
    • d) Carbon dioxide and starch

  6. 6.The large intestine is shorter than the small intestine. Why is it called large?

    • a) It was discovered before the small intestine was
    • b) It holds more food at one time than the stomach
    • c) It does more of the digesting than any other part
    • d) It is wider than the small intestine

  7. 7.A frog begins life as a tadpole in water and grows into an adult that spends time on land. How does its breathing change?

    • a) The tadpole uses gills; the adult uses lungs on land and its skin in water
    • b) It uses gills throughout, in water and on land alike
    • c) The tadpole uses lungs; the adult uses gills
    • d) It uses its skin throughout, and the lungs do nothing

  8. 8.A cow brings partially digested grass back up to its mouth and chews it thoroughly. What is that process called?

Answer key — Year 8 Science — Life processes in animals

  1. 1. b) They increase the surface area, so nutrients are absorbed efficiently
  2. 2. 4 — Small intestine
  3. 3. 1. Mouth 2. Oesophagus 3. Stomach 4. Small intestine 5. Large intestine 6. Rectum 7. Anus
  4. 4. Lion → Breathes with lungs; Snake → Breathes with lungs; Fish → Breathes with gills; Tadpole → Breathes with gills; Earthworm → Breathes through moist skin
  5. 5. c) Carbon dioxide, water and energy
  6. 6. d) It is wider than the small intestine
  7. 7. a) The tadpole uses gills; the adult uses lungs on land and its skin in water
  8. 8. rumination