Science

Autumn 1

The children have been learning about evolution and adaptation this week. They have explored how living things have changed over time and how fossils provide evidence for how organisms have developed. The children have learned about Charles Darwin and his theory of evolution by natural selection.

How horses evolved over millions of years

• About 55 million years ago – Eohippus: An early ancestor of the horse was small, about the size of a small dog. It had several toes on each foot and lived mainly in forests.
• About 37 million years ago – Mesohippus: Horses became larger and taller, with longer legs. They had fewer toes and were better suited to moving over open ground.
• About 17 million years ago – Merychippus: Horses became larger and developed a single main hoof, helping them run efficiently across grasslands.
• About 4 million years ago – early Equus: Horses became increasingly similar to modern horses, with long legs, strong teeth and a single hoof.
• Today – Equus: Modern horses have one hoof on each foot, long legs and teeth adapted for eating grass.

Key idea for children

Horses did not suddenly change from one type into another. There was variation within populations, and horses with characteristics that helped them survive and reproduce were more likely to pass those characteristics to their offspring. Over many generations, these changes resulted in the horses we see today.