Grown-up notes

Each line is marked Fact well established, Model a deliberate simplification, or Unsure not settled.

Play another way

Another connection: How long ago is long ago?

The idea

• FactAll living things on Earth are related. Any two of them, however different, share ancestors if you go back far enough. Fossils and DNA both show this.
• FactPeople are apes. We did not descend from any chimp or monkey alive today. We share earlier ancestors with them; our family branches have both kept changing.
• FactEvolution is change in populations across generations. Individuals grow and develop, but do not evolve into another species during their lives. Inherited differences can become more or less common through selection and chance; change has no intended destination.
• FactEvery tip shown is alive today. The tree shows relationships, not a ranking of better or more evolved creatures. People are one tip among millions.
• FactOur own species began in Africa. The oldest fossils found so far are about 300,000 years old, from Morocco.
• FactFrom Africa, people spread over the whole world, a little further with each generation.

What the pictures simplify

• ModelTwelve tips. The real tree has millions. The twelve were chosen because she knows them and because several are Australian.
• UnsureWhen the lines join. The order of the joins is well established. The dates are estimates. The tree uses, in millions of years: chimps 6 to 7; dogs about 95; kangaroos about 160; platypuses about 180; lizards and birds about 320; frogs about 350; fish about 430; insects about 700; fungi about 1,300; plants about 1,500. The oldest three could be out by hundreds of millions of years.
• ModelSqueezed time. The time strip is not even. If it were, everything since the dinosaurs would be a sliver at the top. The small dinosaur on the strip marks 66 million years ago, when the last big dinosaurs died out.
• ModelA join is not one animal. Each dot stands for a whole population living over a long time, not a single creature or a single pair.
• ModelAncestors as plain dots. Fossils tell us a good deal about what some ancestors were like, but none was any animal alive today, so none is drawn as one.
• ModelOne of each. "Fish" stands for the bony fish such as goldfish, "lizard" for lizards and snakes, and "kookaburra" for all birds.
• ModelThe little animal in "Many babies" is made up. Each individual keeps its own appearance; small differences across generations can go in either direction. The slider revisits a recorded, invented lineage, not one animal changing. This illustrates resemblance and accumulated variation. It is not a simulation of genes, populations or natural selection, and the last animal is not better than the first.
• Model"Your family" counts birth parents. Families come in many shapes, and the people who raise a child are her family whoever they are.
• ModelThe map is a rough sketch and the routes are guesses at the general direction. Seas were lower then, so some crossings were shorter than they look.
• UnsureWhen people arrived. The map uses: leaving Africa about 65,000 years ago; Australia about 55,000; Europe about 45,000; the Americas about 17,000; New Zealand about 750. All are argued over. For Australia, one site has been dated to 65,000 years and some researchers think 50,000 to 55,000 is safer.
• ModelOther humans left out. Other kinds of human, such as Neanderthals, lived at the same time as early people and are not shown.

Questions she may ask

• Did people come from monkeys? FactNot from monkeys alive today. We share ancestors with other primates. People are one kind of ape, and chimps are another; neither living species turned into the other.
• Then why are there still chimps? FactBecause chimps did not turn into people. Both family lines started from the same ancestor and both kept going.
• Were my great-great-grandparents fish? FactIf you go back far enough, yes: your ancestors were animals that lived in water and looked something like fish. They were not any fish alive today.
• Who was the first person? FactThere was no single first baby born to non-human parents. Features of our species emerged in populations over many generations; scientists use names to describe parts of that branching history.
• Why do people look different from each other? FactFamilies who lived in different places for a very long time came to differ a little, in skin and hair for example. All people are one family and are far more alike than different.
• How did life start? UnsureNobody knows yet. Living things have been on Earth for more than three and a half billion years, and scientists are still working out how the first ones began.
• Is this what everyone believes? A neutral answer: "This is what scientists have worked out by looking very carefully at bones and at living things. Many families also have stories about where people came from, from their religion or their culture, and those stories matter to them. Lots of people hold both."

Words this guide teaches

Ancestor: a great-great-great-grandparent from long ago. Cousins: relatives who share an ancestor. Generation: parents are one generation, their children are the next.

Go further

The Australian Museum in Sydney is open daily and general entry is free. Check its visiting page for what is on.

Grandmother Fish: A Child's First Book of Evolution by Jonathan Tweet, illustrated by Karen Lewis (2016), is written for ages three to seven and is meant to be acted out together.

Sources

• UC Berkeley, Understanding Evolution: population change, common ancestry and why evolution is not progress towards a goal.
• Smithsonian Human Origins, introduction to human evolution: our relationship with other apes and the branching human family.
• Hublin and others, Nature, 2017: the 300,000-year-old fossils from Jebel Irhoud, Morocco.
• Clarkson and others, Nature, 2017: people in northern Australia by 65,000 years ago, a date others dispute.
• TimeTree: published estimates of when family lines split.
• Australian Museum: visiting.

Checked November 2026. Of the split dates, only those for insects and fungi were confirmed against a source during checking; the others are widely published figures recalled, not looked up. The same is true of the dates for Europe, the Americas and New Zealand. The fact-check log in notes.md lists each one.