VOL 4 Test 5 - Gastropods (snails and slugs)

Evolution

• minerals in the bodies of gastropods are like those in the 1
• fossils date back 500 million years

Physical features

• single, muscular foot
• radula (used for feeding)
• Shell (snails only)
• size: British shells range from 1.5-50 mm
• form: most shells coil to the 2
• some shells have ribs, spines or 3
• they have various colours and patterns

Feeding habits

• mainly feed on rotting plants, fungi or algae
• some eat live animals, e.g. shield slugs eat 4

Predators

• birds, frogs, flies
• humans - snails were probably introduced to Britain as food in the 5
• many gastropods have particular types of 6 itself slippery...e.g. glutinous snail makes

Habitats

• gastropods prefer dampness and shade
• 7 conditions are worst
• biggest variety is found in old, natural habitats, e.g. 8 and meadowland
• highly specialised species live in unusual habitats, e.g. blind snail lives entirely below the 9
• good indicators of the quality of the 10