Question

Numerous large mammal creatures wiped out after the last ice age as temperatures expanded. Besides hunting by humans, based on the surface to volume ratio and gestation of young what might be the reason for their extinction.

Answer 1

The extinction that occures near the end of the last ice age was strange and different from any previous extinction. There was much glacial melting and ice accumulation occured during the start of Ice age extinction. It became dangerous for the large animals on land than ocean animals. Except Africa there were much extinction on all the continents.

Reasons for extinction:

• The extinction of large animals is due to melting of glaciers and loss of food supply.
• The Glacial ice covered more than quarter of the earth and the end of the period occured when most of the continental glacies broke up and melted causing rise in the sea level.
• About 28,000 years ago in the high latitudes the cold surface temperatures due to cold water on the surface of the oceans, evaporation of water didinot take place with lower moisture in the atmosphere. Whereas in the lower and mid latitudes, there was much evaporation and more moisture in the air causing more snowfall over the glaciers away from the poles. As Glacier building exceeded the melting, the glaciers grew and increased causing polar glaciers contracting and mid latitude glaciers expanding.
• About 18,000 years ago, ice melting exceeded ice formation and glaciers began to recede flowing to the oceans. This caused the breaking off large icebergs.
• The icesheets floated off the ocean floors and their melting the level of oceans to 350 feet.
• The large animal extinction started in Australia with the major melting of large ice sheet in East Australia followed by North America, South America, Europe , Asia and Africa. Changes in the oceans and atmosphere near the end of ice age are intimately associated with the large animal extinction.
• The changes in the input of heat energy affected the internal dynamics of oceans and the atmosphere.
• The large wind blown dust deposits called loess and sand dune fields formed end of last ice age.
• The plant diversity became sparse in the high latitudes.
• There was an explosion of human population and migration at the end of last ice age.
• There is decline in carbondioxide level where plants cannot survive