Friday, 7 November 2014

Insect Family Tree Formulated

insect family

For the first time, the most comprehensive insect family tree has been devised by an international research team, which was revealed on Tuesday. The origin of the insects has been traced back to about half a billion years ago, making use of the genetic data which also provided a better insight about the interrelationships 

among the major group of insects. In terms of diversity and enormity, the insect group ranks first among all the animals. To outline their evolution and diversification, 1478 genes belonging to 144 species have been analyzed by the scientists, encompassing all the major groups. Bernhard Misof from the Zoological Research Museum Alexander Koenig in Germany, who is also among the leaders of the study published in the journal Science, stated “two-thirds of all known animal species are insects. They are the important players in terrestrial ecosystems, together with plants.”
On the basis of the genetic data, it has been evaluated that it was around 480 million years ago when the first insect appeared, coinciding with the appearance of first land plants. The date in fact goes beyond the oldest-known insect fossil, by 70 million years. Another leader of the study, Karl Kjer, an evolutionary biologist from Rutgers University in New Jersey, elucidated “the Earth 480 million years ago looked more like Mars than our Earth today: nothing but rock, with no life on land. The oceans were full of life, but life out of the water is really quite challenging.” He further added “plants and insects co-evolved simultaneously, each shaping the other.”
According to Misof, the first terrestrial plants must have formed the prerequisite, in the form of organic food, for the evolution of insects on land. Scientists predict that it was remipedia, a group of venomous crustaceans, which served as the precursor for the evolution of first insects. Misof also elaborated “we have absolutely no clue of how the first terrestrial insects might have looked, but somehow they must have resembled an animal with crustacean and insect features.”
Scientists opine that around 400 million years ago, the appearance of the first winged insects was marked which owes to the fact that the terrestrial plants started growing skywards by then, forming forests. The evolution of any other flying animal began approximately 200 million years after this. It has been estimated that the first winged insect appeared much before the time specified by the fossil record. The most ancient insect wing fossil dates back to about 340 million years. According to the research the Cretaceous Period, which marks the end of dinosaurs, witnessed the proliferation of flowering plants along with expansion in the diversity of flying insects like moths, butterflies, beetles, wasps and flies. However Misof clarified that these groups originated much earlier, about 350 million years ago. About 252 million years ago, the Earth witnessed the worst extinction in its history and the evolution of diverse termites and cockroaches is the consequence of the same. However scientists are still pondering over the reason of this mass fatality which caused a number of land and sea creatures to vanish forever
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