Misconceptions

A student recently interviewed me for an English assignment, meant to probe a professional in her field of biology. One of the questions she asked, and my answer, was:

Any common misconceptions about Biology?

Sure there are lots of misconceptions about biology, or aspects of biology. The whole concept of a 'balance of nature' is probably one. It is a steady-state concept, whereas most ecologists and other biologists now accept that ecosystems are dynamic, constantly changing, with outcomes of organismal interactions shifting back and forth. In my own field of evolutionary biology we are constantly faced with misconceptions. A common one might be that organisms do things 'for the good of the species'. This is completely incorrect. Oranisms do things to maximize their individual fitness (survival and reproduction). Period. 

During my time teaching evolution I always began by enumerating some of the misconceptions about this process. I recreate these here.

Common misconceptions about evolution

• Evolution is a process of perfecting organisms.

     -Organisms are rarely perfectly adapted. They are as adapted as they can be in their current environment, given past history.

• Evolution is progressive, striving toward a goal.

     - The history of life is like a bush, not a ladder (leading to humans).

• Evolution is a random process.

     - There are random processes in evolution but natural selection is deterministic, selective.

• Natural selection = evolution.

     - Natural selection is only one mechanism of evolution.

• Organisms change because they “need” to.

     - Mutation is random. If a population has variants that reproduce more than others in a given environment the population will change. 

• Evolution explains the origin of life.

     - Evolution is about organic history. It’s what happened after life began.

•Adaptations are for the good of the species.

     - Adaptations are preserved because individuals that have them reproduce better than those that don’t, not because they perpetuate the species.

• Microevolution and macroevolution are distinct processes.

     - Speciation (formation of new species) and extinction are the only processes that occur above the species level. It's the relative rates of each that determine macroevolutionary patterns.