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.

The diagram provides a detailed overview of the evolutionary process of the horse, highlighting the significant increase in body

size

Use synonyms

and the structural evolution of its

foot

Use synonyms

bones.

Overall

Linking Words

, the development of horses has undergone four distinct stages over a span of 40

million

Use synonyms

years

Use synonyms

, beginning with Eohippus and culminating in the modern horse.

Additionally

Linking Words

, the bone

structure

Use synonyms

of their feet has become simpler,

while

Linking Words

their bodies have grown larger over time. As shown in the diagram, the earliest horses, scientifically known as Eohippus, first appeared 40

million

Use synonyms

years

Use synonyms

ago. These species were characterized by their small body

size

Use synonyms

and complex

foot

Use synonyms

bone

structure

Use synonyms

, which featured four slender digits. Over the following 10

million

Use synonyms

years

Use synonyms

, the presence of Mesohippus was recorded, displaying a larger body

size

Use synonyms

and a

foot

Use synonyms

structure

Use synonyms

with only three digits, the middle one being the largest. Approximately 15

million

Use synonyms

years

Use synonyms

ago,

while

Linking Words

the

foot

Use synonyms

bone

structure

Use synonyms

of Merychippus remained identical to that of Mesohippus, its

overall

Linking Words

size

Use synonyms

increased significantly.

Finally

Linking Words

, the modern horse, the largest among its predecessors, evolved a completely different

foot

Use synonyms

structure

Use synonyms

. All toes fused into a single hoof, enhancing its upright posture and stability.