3.77 Billion years ago – The earliest known life forms on Earth are fossilized microorganisms found in hydrothermal vent precipitates — not long after the oceans formed and not long after the formation of the Earth – 4.54 Billion yeas ago. 99+% of all species of life forms are now EXTINCT or 5+ billion species are gone. Today about 10 millions life forms still live on earth with 86% not even found and documented. Some researchers think there are a 1 trillion species currently on Earth. 2016 Scientists reported identifying a set of 355 genes in the Last Universal Common Ancestor (LUCA) pool of organisms living on Earth. According to one researcher, “You can find microbes everywhere — they’re extremely adaptable to conditions, and survive wherever they are.”

Click for Source Article on First Living Beings & Humans

15 Million years ago — Hominidae or great apes, ancestors of the gibbon (lesser apes) appeared.

13 Million years ago — Homininae were ancestors of the orangutan and is believed to be a common ancestor of humans and the other great apes, or at least a species that brings us closer to a common ancestor than any previous fossil discovery. It had tree climbing abilities and had a wide, flat rib cage, a stiff lower spine, flexible wrists, and shoulder blades that lie along its back.

10 Million years ago — The chimpanzees and bonobos (Pan genus) were ancestors of the gorillas.

7 Million years ago — Hominina (Sahelanthropus tchadensis), a subtribe of Hominini (now extinct) were close ancestors to humans & chimpanzees. Both chimpanzees and humans have a larynx that repositions during the first two years of life to a spot between the pharynx and the lungs, indicating that the common ancestors have this feature, a precondition for vocalized speech in humans. This sub-tribe was the latest common ancestor of humans and chimpanzees and both separated into different branches.

6 Million years ago — Earliest known representative of ancestral human separate from chimpanzee lines is Orrorin tugenensis or Millennium Man in Kenya.

4.4 Million years ago — Very early Ardipithecus had a small brain about the size of today’s chimpanzee brain or 20% the size of modern Humans (Homo sapiens), and was smaller than the brain of Lucy which was 25% bigger. They lived in the forest and competed with other forest animals (like chimpanzees) for food. It could stand on its two hind legs, had thinner wrist bones, but its feet were still adapted for grasping limbs rather than walking for long distances.

3.6 Million years ago — Australopithecus afarensis left human-like footprints on volcanic ash in Laetoli, Kenya, now Northern Tanzania, so it was more human like, and is considered one of the earliest hominins with lineage to Homo sapiens. Compared to the modern and extinct great apes, they had smaller teeth — canines and molars were still relatively larger than in modern humans. But it still had a smaller brain than Lucy size (380–430 cm³) and a face located on or near the front of the body. They were scavengers and ate meat.

3.5 Million–3.3 Million years ago — Kenyanthropus platyops, a possible ancestor of Homo sapiens created stone tools deliberately.

3 Million years ago — Walking australopithecines (a sub-tribe of Hominina) lived in the savannas of Africa (semi-arid) and were hunted by a large now extinct sabre-toothed Cat (Dinofelis), that numbered in the millions around the world but became extinct 1.2 million years ago. These semi-humans lost their body hair and became very runners.

2.8 Million years ago — Homo habilis appears in East Africa and are considered the first human ancestors after splitting from the chimpanzees. They developed and mastered creating sophisticated stone tools at the beginning of the Lower Paleolithic Era (3.3 million years ago to 250,000 years ago). It existed until around 1.5 million years ago and evolved into African Homo erectus.

1.8 Million years ago — Homo erectus in Africa looks strikingly like modern humans, but had a brain about 74% the size of modern man. Its forehead is less sloping than that of Homo habilis and the teeth are smaller. Homo georgicus found in today’s Republic of Georgia was much like a modern human in standing and could cover very long distances to follow herds of animals they hunted. This was the oldest fossil of a hominin found outside of Africa, and obviously had travelled there for hunting purposes.

1.5 Million-1.2 Million years ago — Homo ergaster learned to control fire. Some were as tall as 6 foot 2 inches and has evolved from ape-like hair to dark skin.

1.2 Millions year ago — Homo antecessor was likely a common ancestor of humans and Neanderthals with around 20,000–25,000 genes that match 99% of DNA of extinct Neanderthals and 95–99% of living chimpanzees. The human variant of the protein encoded in the FOXP2 gene (Forkhead box protein P2) linked to the control of speech and language (SPCH1) has been found to be identical in Neanderthals.

700,000 years ago Homo pekinensis first appears in Asia but were an offshoot cousin species from Homo erectus. Homo heidelbergensis was a very large hominin that developed a more advanced complement of cutting tools and may have hunted big game such as horses.

600,000 years ago Homo heidelbergensis was 5 feet tall and left footprints in powdery volcanic ash solidified in Italy and were likely common ancestor of humans and Neanderthals. They were very similar to Homo erectus but had a larger brain-case, about 93% the size of that of today’s Homo sapiens. They evolved to being 6 foot tall and more muscular than modern humans.

500,000 years ago as the Middle Paleolithic era was starting the Neanderthal evolution diverged to path to Homo sapien ancestry.

250,000 years ago — Around the Omo River in Ethiopia the earliest fossil evidence for modern Homo sapiens was found as the theoretical Y-chromosomal Adam of East Africa the oldest common ancestor of all male human Y chromosomes.

160,000 Fossilized skulls of two adults and one child Homo sapiens were discovered in Afar. Region of eastern Ethiopia, along the Awash River (near present-day Herto village). These are the oldest known fossils of modern humans, or Homo sapiens and filled a major gap in the human fossil record, an era at the dawn of modern humans when the facial features and brain cases we anatomically recognize today as human first appeared. They practiced mortuary rituals and other aspects of behavior of modern humans, including art & fishing.

200,000-99,000 years ago — The hypothetical East African Mitochondrial Eve was mother of all currently living humans. All humans descended from this woman in an unbroken line purely through their mothers.

90,000 years ago — Appearance of mitochondrial haplogroup L2 is a group of similar DNA to humans.

60,000 years ago — Appearance of mitochondrial haplogroups M and N, which migrated out of Africa. And these Homo sapiens who leave Africa in this wave may have interbred with the Neanderthals they encounter.

50,000 years ago — Modern human behaviors develop and many humans migrate out of Africa over next thousand+ years to inhabit India and Asia. These migrants became unique with the M168 mutation (of non-African males). This was also the beginning of the Upper (last) Paleolithic Stone Tool age period lasting to 10,000 years ago when both Bronze production and farming begin. Two other DNA groups appear, U and K. The K group makes up between 10% and 20% of populations in Europe. The U group covers Western Siberia, among ancient Egyptian mummies, Canary Islands.

40,000 years ago — Homo sapiens migrated to Australia and Europe. In Europe with the earliest known remains radiocarbon dated to 40,000–45,000 years ago and were found in Italy, England, and Russia. This species were robustly built, powerful, heavy, and solid with fairly straight foreheads unlike sloping foreheads of Neanderthals, and with only slight browridges. These European faces were short and wide and the chin was prominent. The brain capacity was larger than the average for modern humans.

25,000 years ago-40,000 years ago — Neanderthal lineage dies out. But three more DNA groups show up, R2, J and X. DNA group R covers wide areas including Australasia, Americas, Southeast Asia, South Asia, Central Asia, West Asia, East Asia, Europe, North Africa and Horn of Africa. DNA group J is about 12% of native European populations and Near East and to a lesser percent in Caucasus, Northeast, Pakistan, West Eurasian lineages, Saudis, Yemenis, Iraqis, Palestinians, Algerians, Sudanese Fulani, Egyptians, and Berber groups. DNA group X is found in the Americas, Europe, Western Asia, North Africa, the Horn of Africa, especially common among Egyptians at one oasis, and most prevelant among Palestinian Druze there for 10s of thousands of years, and Morocco.

10,000 years ago–20,000 years ago was the beginning of the Mesolithic/Holocene, the period between Paleolithic and Neolithic and was pre-farming and pre-Bronze. It was the period of evolution for light skin in Europeans. First appearance of DNA groups V & T. DNA group V is only 4% of native Europeans with highest concentration in northern Scandinavia, Volga-Ural region, northern Iberia, Basque region, Northwest Africa, Western Sahara, Berbers of Matmata, Tunisia. DNA group T is found in Algerians, Western and Central Asia and Europe, Iranians, Central Asian & modern Turkic populations including those from Kazakh steppe, is low in Britain and Ireland, high in Saudi Arabia, Sephardic Jews of Turkey and Bulgaria, Jews in the New World, Caucasus (Georgia-Khazars), Central Asia, deep into North Asia and Mongolia, Cyprus, and Modern South Arabia.