Put simply, evolution is a process by which the heritable characteristics of a population of living organisms change over successive generations.
This process is primarily driven by random genetic mutations and natural selection, though it should not be confused with these closely related yet distinct processes.
- What does 'survival of the fittest' really mean?
- Evolution explained: what evolution is, how evolution works - and how some dinosaurs turned into birds
- "We owe our existence to an unlikely moment 350- million years ago when a prehistoric fish hauled itself out of the water. But why did this just happen once?"
It’s best to think of evolution as the engine of a car, and these other processes as the fuel that powers this engine.
There are four main patterns of evolution, each driven by a combination of random genetic mutations, natural selection, and other mechanisms such as genetic drift, gene flow, and migration. These are: divergent evolution, convergent evolution, parallel evolution, and coevolution.
- In divergent evolution, related species evolve different traits, typically after the population of a common ancestor splits following some kind of separation event. Think Darwin’s finches; these birds shared a common ancestor but evolved different beak shapes after spreading to different, geographically isolated islands.
- In convergent evolution, unrelated species evolve similar traits as a result of living in similar environments and facing similar selection pressures. This is best displayed by sharks and dolphins, which look very similar despite diverging from one another more than 400 million years ago.
- While similar, parallel evolution describes how related species evolve similar traits independently, starting from a similar ancestor.
- The last pattern, coevolution, describes a process where two or more species affect one another’s evolutionary journey through close ecological interactions.
The big takeaway here is that while evolution often creates new species, this isn’t necessarily an inherent part of the process. It’s possible a population of living organisms sharing similar characteristics evolves without becoming a new species.
- How long does evolution take?
- How one remarkable cell transformed simple prehistoric sea creatures into today's complex animals of land, sea and sky
- Does the tree of life reflect evolution?
- A fish that's bad at swimming, a bird that doesn't know its own chicks: These are evolution's greatest fails
- What could aliens look like? How could evolution work on other planets?
