Science

Common mistakes in evolution and natural selection

7 mistakes learners make with evolution and natural selection, each one named and explained.

All common mistakes

Variation already exists; the environment decides which variants leave more offspring.

A famous scientist attached to the wrong idea

What it looks like

Newton or Curie is named as the originator of a biological theory.

Why it happens

Famous scientists are learned as a list of names before they are learned as a list of ideas.

A worked example

Question. Who proposed natural selection

A common answer. Isaac Newton

The answer. Charles Darwin

Why. Newton worked on forces and light, and lived two centuries earlier.

Put the two side by side

Newton: forces and motion.
Darwin: evolution by natural selection.

Attach each name to one idea and one subject. The subject alone rules most of them out.

Animals thought to change themselves to suit the environment

What it looks like

You explain natural selection as animals adapting themselves, or needing a feature and growing it.

Why it happens

It is the intuitive story, and it is the one most nature documentaries imply.

A worked example

Question. How giraffes came to have long necks

A common answer. they stretched their necks and passed the longer neck on

The answer. the ones already born with longer necks fed better and left more offspring

Why. Stretching your own neck does not change the DNA in your gametes.

Put the two side by side

Lamarck: the individual changes, then passes the change on.
Darwin: the individuals already differ, and the environment selects.

Nothing an animal does to itself gets inherited. The variation has to be there first.

Evidence chosen that answers a different question

What it looks like

Fossils are said to be useful because they tell us about today's weather or what animals eat now.

Why it happens

The statement offered is not false in itself, so it does not trigger any alarm.

A worked example

Question. Why fossils are useful evidence for evolution

A common answer. they tell us what animals eat now

The answer. they show how organisms have changed over time

Why. Evolution is about change across time, so the evidence has to be about time.

Put the two side by side

A true statement about fossils.
A true statement about evolution.

Check the evidence answers the question asked, not just that it is true.

Fittest read as strongest

What it looks like

Natural selection is explained as the strongest or biggest animal always winning.

Why it happens

Survival of the fittest is a famous phrase and fit means strong in every other context.

A worked example

Question. What fittest means in natural selection

A common answer. the strongest animal

The answer. the one best suited to that environment

Why. In a cold environment the fittest may be the smallest, because it loses less heat.

Put the two side by side

Strongest is one way to be well suited.
Best camouflaged, best at digesting a food, best at surviving a drought are others.

Fittest means best fitting the environment, the way a key fits a lock.

Mendel credited with natural selection

What it looks like

Gregor Mendel is given as the person who proposed evolution by natural selection.

Why it happens

Mendel is the other famous name in this topic, and both worked on inheritance.

A worked example

Question. Who proposed evolution by natural selection

A common answer. Gregor Mendel

The answer. Charles Darwin

Why. Mendel worked out how inheritance works, using pea plants.

Put the two side by side

Darwin: natural selection, from the variation he saw.
Mendel: the rules of inheritance, from breeding peas.

Two different questions. Darwin asked why species change; Mendel asked how traits pass on.

Species thought never to change

What it looks like

Fossils are described as proving that animals have always stayed the same.

Why it happens

Living things look fixed over a human lifetime, because the change is far slower than that.

A worked example

Question. Why fossils are evidence for evolution

A common answer. they prove animals never change

The answer. they show how organisms have changed over time

Why. Fossils from different rock layers show different forms of the same lineage.

Put the two side by side

Over one lifetime, nothing seems to change.
Over millions of years, the fossil record changes completely.

Evolution is invisible at human timescales. That is why the evidence is in the rocks.

Variation and adaptation used as the same word

What it looks like

The differences between individuals of one species are called adaptation.

Why it happens

Both words describe how living things suit their surroundings, and both appear in the same topic.

A worked example

Question. Differences between individuals of the same species

A common answer. adaptation

The answer. variation

Why. An adaptation is a feature that suits an environment; variation is simply that individuals differ.

Put the two side by side

Variation is the raw material: everyone is slightly different.
Adaptation is the outcome: the useful differences become common.

Variation comes first and exists anyway. Adaptation is what natural selection does with it.

WAJD spots these patterns in your child's answers and names the one behind their wrong answers, instead of just marking them wrong.

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