Reading through even just a third of The Greatest Show on Earth: The Evidence for Evolution by Richard Dawkins, the celebrated biologist, one is armed with enough aha! moments and anti-charlatan detectors to fill a season of Oprah and perhaps half one of Mythbusters respectively.
There are efforts to question the status of the theory among what creationists, religious apologists and conservatives see as its more established brethren; they are perfectly convinced by the theory of gravitation and fluid dynamics, even though these are just that—theories. Opponents of evolution are motivated by either sheer misapprehension or plain-old duplicity, but let’s not impugn motives and rather gamely assume the former. It’s a position that could be caused by any number of misconceptions about evolution. Let’s quickly parry these away, in point form.
1. How can you get life out of non-life?
- Evolution is about a change in a population of organisms over time.
- The origin of life is a separate branch of biology and an active area of research.
- There is no answer to this for now. There’s been one experiment showing you can get the basic ingredients of life under primitive conditions.
2. Animals can’t change forms! Seen a monkey turn human?
- There is no essential form of animal, they all lie on a continuous spectrum. The question is whether it’s different enough to deserve a different name.
- (Also, humans are cousins of monkeys: they share a common ancestor, at least two of whose populations split and diverged ultimately into these two species.)
3. There! You said it’s a theory. So it’s just a theory!
- Scientists use ‘hypothesis’ to refer to untested claims. They should strictly use ‘theory’ to mean verified claims but use it to refer to a hypothesis as well.
- A theory in the former sense is known generally as a fact. Evolution is a secure a fact as any other. But yes, it’s less precise than physics, described by mathematics.
4. But where is the missing link?
- Evolution is a continuous spectrum, so specifying discrete forms misses the point.
- Fossils are rare because it takes special conditions to make them. For example, the body must lie in sediment. As most dead animals don’t fossilise, gaps are expected.
- It’s not a useful counterargument as if you get a missing link, two new ‘gaps’ appear.
5. Why don’t we see animals evolving around us then?
- Because interesting, obvious evolution takes a long time. We tend to forget about the everyday artificial selection that has driven the evolution of plants and pets.
- In the 1970s a population of lizards was transplanted on a neighbouring island. Over three decades, their heads and digestive tracts changed to accommodate the more herbivorous diet the island supported.
6. What is the strongest evidence for evolution?
- Modern genetics. Through DNA analysis we know that all organisms ever observed have DNA in common and thus have a common ancestor.
7. What is the other evidence?
- Fossilisation: slightly different traits are shared across species.
- Geographic distribution: Animals are slightly different but share basic traits across the globe. This is possible because evolution took place.
- Vestigial parts: parts that are not used anymore or modified for a different purpose are left over from ancestors.