GENETICS AND EVOLUTION
EVOLUTION
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
The digits of the horses’ feet underwent modifications, enabling them to run faster from predators.
|
|
|
The molars of the horses underwent changes so they could chew meat.
|
|
|
The emergence of grasslands over time led to the development of strong molar teeth in horses.
|
|
|
The digits were modified to enable the horses to graze better on hard, rocky surfaces.
|
Detailed explanation-1: -Evolution. The very first horses evolved on the North American grasslands over 55 million years ago. Then, they deserted North America and migrated across the Bering land bridge into what is now Siberia. From there, they spread west across Asia into Europe and south to the Middle East and Northern Africa.
Detailed explanation-2: -The original sequence of species believed to have evolved into the horse was based on fossils discovered in North America in 1879 by paleontologist Othniel Charles Marsh.
Detailed explanation-3: -Thus the classic story of horse evolution was formed: as grasslands took over from forests, the horse gradually evolved larger body size (perhaps to better defend against predators), taller-crowned teeth to handle abrasive grasses, and long, monodactyl limbs to race away from predators in their newly open habitat (Fig.
Detailed explanation-4: -Evidence from Fossils The fossil record reveals how horses evolved. The lineage that led to modern horses (Equus) grew taller over time (from the 0.4 m Hyracotherium in early Eocene to the 1.6 m Equus). This lineage also developed longer molar teeth and the degeneration of the outer phalanges on the feet.