LYFE CYCLES IN ANIMALS INSECT METAMORPHOSIS

Physical changes from one stage in life cycle to another. TWO TYPES OF METAMORPHOSIS: 1.Complete metamorphosis 2.Incomplete metamorphosis METAMORPHOSIS

Comparison of metamorphosis 88 % of all insects12 % of 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

Complete metamorphosis

Incomplete metamorphosis

Advantages and disadvantages of complete metamorphosis Advantages: 1.Larva and adult occupy different habitats and niches – not in competition. 2.Carrying capacity of ecosystem increased. 3.Egg and pupa stages allow insect to survive unfavourable conditions. Disadvantages: 1.Larval forms vulnerable to predators. 2.Suitable habitat for laying of eggs needed. 3.Change from pupa to adult requires high energy-input.

Advantages and disadvantages of incomplete metamorphosis Advantages: 1.Vulnerable pupa stage avoided. 2.Less energy is needed – no drastic changes from pupa to adult. 3.All stages can eat same food. Disadvantages: 1.Nymph and adult often compete for same food. 2.Insect vulnerable to dehydration and predators when moulting. 3.Entire insect population could be threatened by environmental changes.

Amphibian metamorphosis