Jaime Gaulzetti

Evolution of African Elephants

Background Information*African elephants are the largest land animals on Earth. *They originated in Africa about 1.5 million years

ago.*They are mammals and herbivores, so they eat

foods such as roots, grasses, and fruit.*African Elephants do not sleep much, and they

roam over great distances while searching for large quantities of food to sustain their massive bodies.*Their average life span in the wild is up to 70

years. *They range from about 8 to 13 feet tall and

from about 5,000 to 14,000 pounds.

Taxonomy*Domain: Eukarya*Kingdom: Animalia*Phylum: Chordata*Class: Mammalia*Order: Proboscidae*Family: Elephantidae*Genus: Loxodonta*Species: africana

*Modern day elephants represent only one of many Proboscid families that have existed throughout history. *Elephant ancestry spans over 55 million years and

includes more than 300 Proboscidean species. *The earliest member of the Order Proboscidea was Moeritherium. Moeritheriums lived during the Eocene epoch about 50 to 55 million years ago. Although the animals did not possess trunks, the structure of the skull indicates they had an elongated snout. *Analysis of skull anatomy reveals all members of the

Elephantidae family had well—developed trunks based on the elevated position of the nostrils.

Evidence of Evolution

Evidence of Evolution cont.*Many complete mastodon skeletons have been discovered from Pleistocene swamps. Mastodons were about the size of modern Asian elephants, with two massive, slightly downward-curved tusks in the upper jaw. *Radiocarbon dating has identified the coexistence of

mastodons and early man, around 10,000 to 12,000 years ago. *Primelephas is presumed to have given rise to other elephant

species, including the modern Asian and African elephants and the mammoth.*Most of our early Proboscidean knowledge of internal and

external anatomy comes from well preserved fossilized remains. A nearly complete fossilized mammoth was discovered in the Soviet Union in 1977. It is estimated to be about 40,000 years old. The tissues are so well preserved, that scientists identified intact red blood cells and ancient proteins.

*The two species of elephants today are the African and Asian elephants. It is possible that they evolved through co-evolution because all of the Proboscideans became extinct except for the African and Asian species. One possible explanation for the disappearance of the other Proboscideans may be found in the inability of the order to evolve to environmental change fast enough. Both of the surviving African and Asian elephants have a wide range of attributes which give them the ability to survive and to even thrive in mild to extreme environmental conditions. *The mammoth, Asian elephant, and African elephant

originated in Africa. It was only the African elephant that ended up staying and evolving to the animal we know today exclusively in Africa. The mammoth became extinct 10,000 years ago. *Fossil records indicate that the hunting by man was a

factor in eliminating the mammoth, as well as global warming.

Means of Evolution

Rate of Evolution*The evolution of African

elephants can be described as punctuated equilibrium because new species changed most at the time they branched from the parent species. *The organisms changed

little as time went on but some species became extinct, and some new species also developed.