Human evolution is one of the most intriguing and interesting topics in the modern day history of science. It took millions, if not billions, of years for the human to come in the present form that we now see. The story of human evolution is long and has many branches departing from it main timeline. Basically the major events that took the shape while development of the human species is known as the timeline of human evolution. The timeline almost covers the possible line of descendants which have connections to human ancestors. The beginning of all species lay in the surfacing of cells with nucleus somewhere around 2100 million years ago.
The timeline includes the first living beings that evolved from the complex cell structure known as eukaryotes and the sexual reproduction also gave rise to faster evolution during this period. The earliest organism to have multicellular structure was a sponge like creature. The flatworms were the first of animals to have a brain. A more complex and developed species were Acorn worm which is sometimes referred as a link between the vertebrate and invertebrate. The primitive chordates were what gave rise to the prehistoric fishes like Placodermi known to be the first fish with jaws. Then afterwards some fresh water fish developed legs and became Tetrapoda, a major turning point in the timeline with a twin lobed brain. An early tetrapod named Icnthyostega developed the first animal-like limbs with finger bones and got dubbed as a hybrid between fish and amphibian. Then the evolution led to the arrival of reptiles.
From the reptiles same various sub groups forming the present day mammals. The early primates were found around 65-85 million years ago. The primates had suborders Haplorrhini and Strepsirrhini the wet nosed primates. Haplorrhini further branches into Platyrrhini which included the New World monkeys and Catarrhini which split into superfamilies Old World monkeys and the apes. It also includes the Proconsul africanus, a so called ancestor of great and lesser apes alongwith humans. Here the color vision trichromatic had its origin.
Around 15 million years ago came the Hominidae, great apes evolving from the gibbon or lesser apes. The vocalization quality arrived from the Homina speciate around 7 million years ago. The Australopithecus afarensis had reduced canines and gave the evidence of full time bipedalism. It had the genus Homo and Australopithecus. The Homo erectus had very similar features to humans and evolved in Africa almost 2.5 million years ago. The Homo heidelbergensis is believed ancestor for humans and had well built body but smaller brain size. The timeline of human evolution depicted the arrival of Homo sapiens around 200k years ago from now. From then on the human race has only progressed to become more sophisticated with time.