Archives de Tag: Darwin

Darwin the terraformer

This is beautiful. Charles Darwin, father of the modern theory of evolution, was also a pioneer of ecology. And with a botanist friend of his, Joseph Hooker (who would become the director of Kew Gardens), he took upon himself to build up an ecosystem (cf. BBC News) on the tiny volcanic island of Ascension, in the middle of the Atlantic ocean.

Kept arid by the hot trade winds from Africa, Ascension Island lacked trees and rainwater, so the two English scientists (with the logistical help of the Royal Navy, for whom Ascension was a useful base of operations) decided to import tall tropical trees in the hope that they would capture moisture from rainclouds, reduce evaporation and enrich the soil with their leaves.

The effect of this artificial vegetation cover? It boosted the evolution of the ecosystem! What would have normally taken tens of thousands, or maybe millions of years, by the slow, gradual process of co-evolution (birds bringing plant seeds with their feces, plants adapting to the new environment, etc.), was accomplished in a matter of decades. There is now a forest on Ascension’s peaks, and it does capture moisture from drifting clouds, and transformed the cinder-like volcanic island into a lush, green, tropical oasis in the midst of the ocean.

Can it get better? Perhaps. Some scientists, among them the British ecologist David Wilkinson, think that the Ascension Island experiment could help devise strategies for the terraformation of other planets, like of course Mars.

From the Victorian pioneers of biological sciences to (maybe) tomorrow’s space conquests? We do live in a world of science fiction!

La coccinelle de Darwin

Allez, tiens, un petit jeu pour perdre du temps sur le Net — euh, pardon, apprendre en s’amusant!

C’est Evolutionary Ladybug (“La coccinelle évolutionniste”), où le but est de guider la coccinelle avec la souris pour lui faire manger les pucerons. On ne gagne rien, mais on voit évoluer la population de pucerons: des individus vert feuille apparaissent (plus difficiles à repérer), leur vitesse moyenne augmente (ils sont plus durs à attraper), etc.

Un joli exemple de modèle informatique d’un système soumis à la sélection naturelle. C’est réalisé par le réseau de recherche en bio-informatique BEACON (Bio/computational Evolution in Action CONsortium), qui regroupe plusieurs universités américaines.

(Source: Blake Stacey et The Panda’s Thumb.)