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Man’s Evolution: Planet Earth

 

Earths Evolution

Earths Evolution

Some 14 billion years ago, the universe was created, and 4.5 billion years ago, our solar system was formed.  Its creation was by way of swirling clouds of electrostatic space dust particles, which attach themselves to each other, forming clusters, which in turn form rocks.

Planets are created, as gravity pulls these rocks together, forming spheres in a process known as accretion (A gradual increase in size, layer by layer).

The Sun, our star was created within a nebula; swirling clouds consisting of dust and gas.

Possibly a shock wave, caused a dying star (Supernova) to explode in space, and dust particles were drawn together, forming a dense sphere like cloud.

So a chain reaction is activated.  More dust is attracted to the core, and its gravitational pull increases, until the cloud collapses in, on itself.

This sees the rotation of the cloud increase in speed.  The rotational forces at the equator of the cloud, prevent dust being drawn in and the cloud flattens into a spinning disc, surrounding the core.

As more and more mass accumulates and so the temperature increases, setting off nuclear reactions.

Our solar system consists of eight planets which orbit the sun; Earth, Jupiter, Mars, Mercury, Neptune, Saturn, Uranus and Venus.

According to the scientific community, it is believed that the Moon was formed, when Earth collided with another astronomical body.

There’s a common origin between the Earth and Moon.  For Earth’s spin and the Moon’s orbit, contain similar orientations, and each contain identical lunar and terrestrial rock.

Therefore, Earth roughly speaking is some 4.5 billion years old, and life began a billion years later, with the appearance of a single celled marine organism.  New forms of life have evolved since that time.

human-evolution

Human Evolutionary Stages of Development

Life forms on Earth, started out with single-celled organisms, followed by multi-celled version which evolved into the fish, an original vertebrate, with a backbone.

As history moves forward we have the Amphibians who evolved from fish and into reptiles, capable of living on dry land.

Evolution of Man

The Evolution of Man

The next stage of evolution saw birds and mammals evolving from reptiles, until the final step … the human being evolved from mammals.

The Paleolithic Age:

  • Creature of the Homo group
  • Homo Habilis – First human species evolved in Africa 2,500,000 BC
  • Homo Habilis – Marked start of Stone Age as stone tool makers

Paleolithic (Old Stone Age) refers to humans who were hunter gatherers.  They who followed an annual migration, based on ripening of plants and travelling of livestock.

Mesolithic (Middle Stone Age) refers to period between hunter-gatherers and agricultural lifestyle.

Neolithic (New Stone Age) where humans existed through agriculture.

Lower Paleolithic, an age of human evolution, which led to an increase in size of the body and brain, of Homo-Sapiens, our modern day humans around 200,000 BC in Africa.

Around 50,000 BC, humans belonging to the Lower and Middle Paleolithic times, exhibited the first signs of primitive behaviour, yet their behaviour resembled a close connection with the animal kingdom.  So the early stages of our evolution, had taken the next step.

Some are known to have migrated out of Africa, and eventually becoming extinct, leaving our world with a single human species; the Homo-Sapiens.  They who would colonize much of the world during the Middle Paleolithic periods.

Some parts of the world opted not to follow an agricultural based lifestyle.  Some continued the old ways of being hunter-gather, and this was followed by Australia, Siberia, Africa and the Americas.  Whilst others followed a nomadic herding lifestyle, where rainfall is sufficient, but grass is scarce.

Neolithic life was the crucial step towards urbanization and Eurasia experienced the rise of cities, thousands of years before the rest of the world.  For they had a plentiful supply of plants and animals, some of which, could be harnessed to undertake heavy labour.

Bronze and Iron Ages:

The Bronze Age started with the development of smelting (A process by which metal is extracted from ore), which had the ability to be shaped, a process which first emerged in Southwest Asia between 3,000-1,000 BC.

Copper was first smelted, but proved to be rather soft, until blended with tin, created a harder metal; Bronze.

The Iron Age arrived in Southwest Asia, around 1,000 BC when iron ore was smelted at much higher temperatures, than that achieved during the Bronze Age.

This transition came about, because it was more abundantly available than copper and tin.  This enabled mass production of tools and weapons, for agriculture and warfare.

Images: Wikipedia

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