You should spend about 40 minutes on this task.
The diagrams below show the development of the horse over a period of 40 million years. Summarise the information by selecting and reporting the main features, and make comparisons where relevant.
Give reasons for your answer and include any relevant examples from your own knowledge or experience.
Write at least 250 words.
The pictures illustrate the evolution of the horse over a 40 million-year period.
Overall, four stages are shown, beginning with Eohippus and ending with the development of the modern horse.
40 million years ago, the first horse, Eohippus, was comparatively small with a short tail. Its defining characteristic, however, was the structure of its foot, which had 4 digits. Each of the digits was
relatively small. 10 million years later, it had evolved into the larger Mesohippus, with a longer tail and a foot structure of 3 digits.
Then, in the next stage of development, Merychippus evolved 15 million years ago. It was a similar size to Mesohippus, and also had 3 digits on its feet, but now the digits on the feet were larger, divided into segments, and the middle digit was very prominent.
Finally, the modern horse evolved. It is bigger than its predecessors, with a large mane and its foot structure is a single, very large digit.