Humans have been present on this Earth for nearly 3.5 million years when "Homo erectus" first evolved with an upright posture enabling the use of hands."Homo erectus" evolved into "Homo sapiens" one hundred thousand years ago and both linegaes lived in small,mobile groups.For nearly two million years,their way of life was based around hunting and gathering food until ten to twelve thousands years ago when agriculture evolved.Early humans depend upon their knowledge of crops and seasons in order for survival.Eventually,as brain size increased and more humans adapted to different environments,advances were made in human technology.Humans began to work with and occasionally against their environment to create a stable way to acquire food as well as a more stable lifestyle.On the other hand,the environment,the climate in particular,definitely dictated the movement and survival methods of early humans.
The seasonal changes,climate and other atmospheric conditions created many challenges for early humans.Modern examples that demonstrate what life might have been like thousands of years ago show that seasons determine where humans can survive.For example,the Bushmen of Southwest Africa live in a consistent climate.They move five or six times a year,but never travel more than ten to twelve miles.On the other hand,the Gidjingalis Aborigines in nothern Australia eat water lilies from full swamps during the wet season,but move to another area during dry season to hunt yam and geese.The Netsilik lnuit living in Canada use their environmental surroundings for all the necessities of life.Their houses are made from snow and ice while their clothing,kayaks,sledges, and tents are made from animal skin.Their tools and weapons made from bones and in the winter are used for seal hunting.In the summer the lnuit hunt caribou and fish for survival.While hunting did cause a strain on some ecosystems,as Clive Ponting states in his book,A Green History of the World:the Environment and the Collapse of Great Civilizations,"all gathering and hunting groups seem to have tried to control their numbers so as not to overtax the resources of their ecosystem.
Even though early humans attempted to not be burdens of their ecosystem,Ponting does point out that "the most dramatic impact that gathering and hunting groups had on their environment though was through hunting animals."Most animals were defenseless against this new predation and overhunting was widespread problem especially since many groups of hunters tended to concentrate on one specific species.In some areas with a lack of plant variety,early humans began to kill large herds of bison and other large animals in very crude and wasteful ways such as luring them off cliffs or into canyons."The changing environment put the greatest strain on these large animals,but hunting by humans would have had a devastating impact on a population already in decline and may have tipped the balance between extinction and survival."
Climate changes definitely played a role in the civilizations of early humans.At the end of the last glaciation period when temperatures were relatively stable,scientists theorize that humans adopted agriculture.The better climate means more resources and vegetation available for humans;therefore,the small mobile groups could begin to reside in one area.Agriculture was a turning point in early human life because humans began to alter their surroundings for survival.The relationship between early humans and their environment is extremely complex.On the other hand,the blossoming of early humans directly caused the extinction or near-extinction of many species as well as possibly affecting the atmosphere and climate.
