Life Cycles

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A life cycle describes all the major growth stages which take place during an individual's lifetime. It includes the production of new members of the species. As the name suggests, life cycles always follow a circular path, arriving back at the same beginning. For example, tadpoles develop from frog spawn. They grow into adults, passing through a series of stages. Adult frogs mate and the female frog produces more frog spawn, from which new tadpoles develop.

All living organisms reproduce and therefore have life cycles. These can take many different forms, although they usually follow the same general pattern.

  • Different stages in a lifecycle may look completely different to each other.
    In animals, a young stage that looks completely different to the adult is often called a larva.

Great Diving Beetle Larva

Great Diving Beetle Adult
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  • Different life cycle stages last for different lengths of time.
    Adults of most species of Mayflies live for a very short length of time, in some cases for only hours. In contrast, the Mayfly larvae may spend one or more years developing in water before they become adult. At the other end of the scale, a mature oak tree may live for several hundred years. It is a seedling for only a very small part of this time.
  • Different stages in a life cycle often occur in completely different habitats.
    For example, adult dragonflies live in air, while the larvae live in water.


mating.JPG (10032 bytes)Click here to follow a fully illustrated dragonfly life cycle.