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LYFE CYCLES IN ANIMALS. INSECT METAMORPHOSIS. METAMORPHOSIS. Physical changes from one stage in life cycle to another. TWO TYPES OF METAMORPHOSIS : 1. Complete metamorphosis 2. Incomplete metamorphosis. 12 % of insects. Comparison of metamorphosis. 88 % of all insects. COMPLETE
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LYFE CYCLES IN ANIMALS INSECT METAMORPHOSIS
METAMORPHOSIS • Physical changes from one stage in life cycle to another. • TWO TYPES OF METAMORPHOSIS: • 1. Complete metamorphosis • 2. Incomplete metamorphosis
12 % of insects Comparison of metamorphosis 88 % of all insects COMPLETE Four stages: 1. egg 2. larva 3. pupa 4. adult E.g. Butterflies, bees, housefly INCOMPLETE Three stages: 1. egg 2. nymph 3. adult E.g. Locust, cricket, cockroach
Advantages and disadvantages of complete metamorphosis Advantages: Larva and adult occupy different habitats and niches – not in competition. Carrying capacity of ecosystem increased. Egg and pupa stages allow insect to survive unfavourable conditions. Disadvantages: Larval forms vulnerable to predators. Suitable habitat for laying of eggs needed. Change from pupa to adult requires high energy-input.
Advantages and disadvantages of incomplete metamorphosis Advantages: Vulnerable pupa stage avoided. Less energy is needed – no drastic changes from pupa to adult. All stages can eat same food. Disadvantages: Nymph and adult often compete for same food. Insect vulnerable to dehydration and predators when moulting. Entire insect population could be threatened by environmental changes.