How biodiversity evolved

The idea

Small differences among individuals affect their survival and reproduction; accumulated over many generations they give rise to new forms of life, so today's diversity results from continuous change over a vast span of time.

Not always the same

The living things we see today were not always the same on the Earth.

What do you think led to so many different forms of life?

• Small differences adding up over a very long time
• One sudden change in a single year
• Nothing changed, they were always like this

Differences build up

Press Next step. The picture is only an example.

Change over a vast span of time

The key idea is that small differences between individuals affect survival and reproduction. When the surroundings change, some differences help individuals adapt. These differences add up over many generations and new forms of life appear.

Small differences among individuals affect survival and reproduction. Accumulated over many generations, they give rise to new forms of life, so today's diversity results from continuous change over a vast span of time.

Notes

Small differences add up over many generations into new forms of life, so today's diversity is the result of continuous change over a vast span of time.

Check yourself

What do small differences among individuals affect?

What gives rise to new forms of life?

Today's diversity is the outcome of ...

What shaped the changes that led to today's diversity?

• Only the colour of the sky. Small differences among individuals affect survival and reproduction, not the sky.
• Their chances of survival and reproduction — correct. Yes!
• Nothing, since they are too small to matter. Small differences can help individuals adapt to changed conditions, so they affect survival and reproduction.
• One difference in one individual in one day. The book says the differences accumulate over many generations.
• Living things staying exactly the same. New forms appear because of change, not because things stay the same.
• Small differences accumulating over many generations — correct. Yes!
• continuous change over a vast span of time — correct. Yes!
• a single change that happened recently. The book says diversity came from continuous changes over a vast span of time.
• organisms staying away from their surroundings. The book says diversity was shaped by interactions between organisms and their surroundings.
• Interactions only among plants. The book speaks of interactions between organisms and their surroundings, which includes animals and plants.
• Interactions between organisms and their surroundings — correct. Yes!
• A system of classification. Classification is a framework for studying diversity. It does not cause the diversity.