Task 2 (M4)
The evolution of the horseTime period Height Modern horse
Fossil remains of dead animals and plants can be found in sedimentary rocks dating back up to 600 million years. These fossils give information about the dominant groups of living organisms at different stages in the development of the earth, although it is not always clear why major changes, e,g, mass extinctions, occurred. Fossils also show how the body structure of individuals within certain groups changed over time, and these changes can often be more confidently related to environmental influence to which these organisms became more efficiently adapted.A prime example of this is shown in the development of the horse, and especially the bones of the foot. The earliest ancestors of modern horses were small, and the feet in contact with the ground had 3 toes. This is presumably a development from the standard pentadactyl limb which most mammals possess.
Later on, horses evolved a larger middle toe and reduced the outer ones.
A horse's leg is thus effectively the equivalent of the human's middle finger, and bends at the wrist!
The development of larger limbs and hooves allowed horses to spread out and become more successful in grassland habitats as they developed.At the same time, the fossils show that horses developed teeth which are more suited to their changing diet - grazing grasses rather than browsing.Each significant in this process can be given a scientific name, similar to classifying living organisms.Many species within the horse family have become extinct, some quite recently.
Later on, horses evolved a larger middle toe and reduced the outer ones.
A horse's leg is thus effectively the equivalent of the human's middle finger, and bends at the wrist!
The development of larger limbs and hooves allowed horses to spread out and become more successful in grassland habitats as they developed.At the same time, the fossils show that horses developed teeth which are more suited to their changing diet - grazing grasses rather than browsing.Each significant in this process can be given a scientific name, similar to classifying living organisms.Many species within the horse family have become extinct, some quite recently.
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The oldest known fossilized remains of bats 50-60 million years ago show that even in the early Eocene, bats looked very much like they do today. Long before human ancestors even resembled apes, bat species similar to species of Microchiroptera today were flying and using echolocation to pursue insects!
Bats represent the only known example of flight in mammals. How this trait evolved, or from where is not certain due to a lack of fossilized evidence. The ‘missing link’ between non-flying mammals and bats is still ‘missing’- and an important piece of the puzzle, without which it is impossible to know with certainty the ancestor of modern bats..
Bats represent the only known example of flight in mammals. How this trait evolved, or from where is not certain due to a lack of fossilized evidence. The ‘missing link’ between non-flying mammals and bats is still ‘missing’- and an important piece of the puzzle, without which it is impossible to know with certainty the ancestor of modern bats..