By David Suzuki
Scientists believe life appeared on Earth almost four-billion years ago, about half a billion years after our relatively young planet formed. It would be fascinating to see how life arose and managed to hang on.
If scientists were to invent time travel to take us back through Earth's history, we'd see little life for most of the four-billion years. Plenty was happening but at a microscopic level as organisms worked out all the intricacies of survival: finding food and energy, evading predators, fighting off disease (even bacteria get virus infections), reproducing and eliminating waste.
Once those fundamental details were worked out, more complex cells arose by incorporating other cells within themselves to perform specialized functions like capturing energy from the sun (photosynthesis) or generating energy from stored molecules. The stage was set for the final blossoming of life into forms visible to creatures like us: multicellularity. Once an organism was made up of many cells, a division of labour was possible. Various cells specialized in movement, eating, digestion, excretion, and reproduction. All of this occurred in the last fifth of life's existence as seas and land filled with wondrous animals and plants.
It's a magnificent story and we only know the barest outlines. We tend to focus on big life forms like trees, elephants and whales. That’s understandable. They’re often spectacular. But our bias toward the big and impressive overlooks the importance, and beauty, of what are often dismissed as “creepy crawlies”, such as worms, insects, fungi, and bacteria.
I was an avid bug collector as a boy. To me, insects were endlessly riveting. Many of them display spectacular colours and patterns and occur in shapes and forms that are far more bizarre and surprising than any Hollywood sci-fi creation. My childhood fascination evolved in college to a focus on heredity in an insect, a common fruit fly, which has revealed so much about genetic principles in humans. More....