Tuesday, May 09, 2006


Insects are small animals around us; they are animals of the class Insecta, the largest and most widely distributed taxon within the phylum Arthropoda. They are invertebrate animals consisting of six legs and the three body parts namely; the head, thorax and abdomen. Most of the insects have one or two and even three pairs of wings.

Ancient types of insects have been available since early dinosaur days and they have been flying before the some of the birds could fly. The sub class Apterygota is divided into two orders, the microcoryphia known as dragonflies, damselflies and the zygentoma known as silverfish, fibre brats. These insects were known to be jumping insects as they were wingless and their habits were, indoors under sinks, stones, bookshelves, in bathrooms, grass, feed, rubble or in woods.

The dragonflies and the damselflies are the insects of the subclass Apterygota that evolved in to the subclass zygentoma, all the insects in the sub class Apterygota are wingless. The reason why these early insects were unable to become very diverse was because they did not have wings. Later the insects gained the ability to explore more territory and find new type of food which increased more species. This resulted as when they evolved the ability to fly. For example: the insects from the microcoryphia order evolved into the Odonato order. These insects had about two pairs of wings and they were regarded as the best fliers, they were eating other insects caught on fight.

The early flying insects developed wings that stuck straight out - as demonstrated by the mayflies and dragonflies, the oldest flying insects alive today. The past 300 million years , other insects had evolved folding wings. This modernism really gave the diversity of insect’s improvement. 'Those insects can keep their wings safely tucked away as they move slowly through leaf litter, squeezed under tree bark or even dived into water'.

The evolution of insects was success and would not be successful without the plants as the insects depend on plants for their survival, because plants provide a large amount of food for the insects. 'The insects evolved defences against the sophisticated chemical weapons in plants. Some of the insects, like monarch butterflies, can recycle poisons from plants they eat, making themselves poisonous to birds and other predators'.

Evolution happens every where, just like in insects evolution took place. 'Some of the insects descended from other insects, for example fleas descend from mosquito and like the insects called scorpion flies, they have long wings and powerful eyes, aiding them in finding insect carcasses for food'.

The knowledge on how the scorpion flies evolved into fleas comes from the fleas' closest living relatives, known as boreids or snow fleas. ‘These 24 species walk across snow in late winter to feed on moss. Unlike other scorpion flies, snow fleas have tiny wings that are useless for flying. They don't have the keen eyesight of other scorpion flies, probably because they need their eyes only to detect predators’.


1. [http://www.universityscience.ie/pages/scimat_evolving_insects.php, accessed on 07/05/2006: 09:00].

2. [http://www.biology-online.org/10/7_insecta.htm, accessed on 07/05/2006: 10:00]

3. The family tree, [http://www.insecta.com/insecta/tree.htm, accessed on 06/05/2006, 12:00].


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