Is there any more charismatic animal than the much maligned koala? Said to "defy evolution", they sleep 20 hours a day, survive solely on eucalyptus leaves - a food source not only nutritionally poor but indeed toxic - and famously don't recognise that food source detached from a tree. And yet, they have not only survived but thrived for more than 25 million years, outcompeting faster, stronger and smarter animals. How is such a thing possible? Koalas are hyper-specialised to a very specific niche: they are the only animal that eats eucalyptus leaves.
A koala sitting in a eucalyptus tree
Pandas, who are more closely related to whales than to koalas, evolved independently to fit the same niche, but with bamboo in place of eucalyptus, in a completely different part of the world. Not only has evolution selected for the dumbest animal alive, it has done it more than once. This adaptation - expending as little energy on brain power, or indeed anything else - works.
Compare koalas and pandas to crows. Crows are famously intelligent, demonstrating tool use, social learning, long term memory and even "metacognition", i.e. thinking about thinking. They dominate not one but many niches all around the world. Crows can survive anywhere. However, their big brains take a lot of energy. Crows are "opportunistic feeders" - they will eat anything, and they expend a lot of energy finding food.
A carrion crow (corvus corone)
An even better example of this high-adaptability high-energy strategy is the common rat. Rats are a pest precisely because they outcompete native species in pretty much any niche they find. They explore their environment, using their advanced spatial awareness to build a "mental map" of the world around them, forming strategies tailored to its specific circumstances.
The trade-off: rats binge-eat. They consume everything they can and won't stop eating when they've had "enough". I often wonder if we hate rats precisely because they remind us of the things we hate about ourselves. Like us, all the destruction wrought by rats, consuming relentlessly, destroying ecosystems, serves one purpose: fuelling their enormous brains so they can survive and reproduce.
Tiny low-energy brains and huge high-energy brains, two wildly divergent survival strategies, both result from the same process: evolution. It seems counter-intuitive, and yet we see something strikingly similar in software development as well. I'm going to do my best now to convince you that it's not just something similar but the same thing.
The Energy Cost Theory of Software Evolution
Both rats and crows exhibit tool use. It's one of those evolutionary strategies that can work very well, and, indeed, it's a strategy that humans take to great extremes. Software is a tool, and, like rats and crows, we use it to increase our chances of survival and reproduction. As such, the forces that drive evolution "bleed" into our tools when we're building them.
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