Why worms rule

I always wonder, what so special that God created the creature known as earthworm. I found the answer today while browsing my Google Alerts. Very nice post.

Science author Christopher Lloyd on why the earth wriggler tops the first league table of species that changed the world

No living thing has had as great an impact on the history of the planet, life and people as has the humble earthworm. That’s the conclusion I have come to after detailing the stories of 100 remarkable species that have changed the world.

Earthworms belong to a family of creatures whose evolutionary past stretches back at least 530 million years, when trilobites first developed sight and marine creatures evolved bones and shells.

Their descendants were among the pioneering creatures that came ashore at the time of the first invertebrate invasions of the land, 450 million years ago, making their living in damp soils broken up by bacteria, fungi and the roots of colonising plants. Ever since, earthworms have been ploughing up the earth, ventilating the soil and nourishing terrestrial ecosystems with their copious excrement.
Five mass extinctions have occurred over the last 500 million years, some of which devastated up to 96 per cent of all marine species and 70 per cent of all land species, but none of them ever touched these remarkable creatures. 

Slice a worm in half and it regrows as if nothing happened. Divide one half and the same thing happens. One worm even survived 40 such butcherings, all in the name of science. The effects of worms on human history are as profound as they are unwritten. French scientist-cum-poet Andre Voisin was one of the few experts who properly highlighted the role of worms in the birth of ancient human civilisations.

Were it not for their continuous regeneration of soils around damp river valleys such as the Nile,Indus and Euphrates, early agricultural societies in Egypt, India and Mesopotamia could never have succeeded in building humanity’s first large-scale urban communities. Even the Egyptian pyramids, said Voisin, were built thanks to the nourishment of the soil by earthworms. It was only because of their hard work that farmers could take time off from tilling the soil to work as a labour force for their pharaoh’s ambitious projects.

When worms perish, societies collapse. Infertile soils led to the demise of the people of ancient Sumeria. Rising levels of salt as a result of irrigating the land with sea water killed off the worms around the mouth of the Euphrates river and the soil turned sour. By 2000 BC their civilisation was so weak from lack of food that they fell easy prey to Assyrian invaders from the north.

It might be easy to think that worms matter little today, replaced by artificial fertilisers and pesticides that guarantee fertility anywhere and everywhere they are spread.

But no. Once again it was largely thanks to the earthworm that the unsustainable nature of using such methods was originally exposed. Rachel Carson was a teacher and environmental campaigner of the 1950s and 1960s. She is famous for warning that Americans might wake up to discover they could no longer hear birds singing in the trees. The reason, she said, was that artificial pesticides, such as DDT, were poisoning the soil.

While robust earthworms are able to tolerate such toxins, for those creatures that eat worms it was a different story. As few as 11 worms that had ingested DDT are enough to poison a robin – either killing it or making it sterile. Since robins regularly eat up to 12 worms an hour the use of DDT put their populations, along with other birds, at risk of annihilation.
Carson’s book Silent Spring (published in 1962) inspired the founding of the US Environmental Protection Agency in 1970. Therefore, the robust digestive system of the earthworms is, in a curious way, inextricably linked to the birth of the modern environmental movement.

If you’re still not convinced that these creatures deserve the ultimate accolade above all other forms of life on Earth, you needn’t just take my word for it. Charles Darwin acknowledged that no other living thing has had such a profound impact on history as has
the earthworm.

So fascinated was he by these humble creatures that he devoted an entire book, published in 1881, to the formation of soil through the action of worms. Here is an extract: “The plough is one of the most ancient and most valuable of man’s inventions, but long before it existed, the land was in fact regularly ploughed, and still continues to be thus ploughed, by earthworms. It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organised creatures.”