The Hadza, or Hadzabe, are an indigenous ethnic group in north-central Tanzania, living around Lake Eyasi in the central Rift Valley and in the neighboring Serengeti Plateau.

The earliest hunter-gatherers in southern Africa were the San people. Hunter-gatherer societies hunt, fish and gather wild plants to survive. They also move around from place to place, following a nomadic way of life. A hunter-gatherer is a human living in a society in which most or all food is obtained by foraging (collecting wild plants and pursuing wild animals). Following the invention of agriculture, hunter-gatherers who did not change have been displaced or conquered by farming or pastoralist groups in most parts of the world.

The movement of a plant in response to an external stimulus in which the direction of response is not determined by the direction of stimulus is called nastic movement.

The Roman style of history was based on the way that the Annals of the Pontifex Maximus, or the Annales Maximi, were recorded. The Annales Maximi include a wide array of information, including religious documents, names of consuls, deaths of priests, and various disasters throughout history. Titus Livius, commonly known as Livy, was a Roman historian best known for his work entitled Ab Urbe Condita, which is a history of Rome "from the founding of the city". He was born in Patavium, which is modern day Padua, in 59 BC and he died there in 17 AD. The Lasting Contributions of Rome. During the early years, Rome was a republic where Roman citizens elected their leaders and created a senate. Branches of the government were balanced in power. This was one of Rome's first attempts at democracy.

The word "settler" is used for the Dutch in South Africa, the British in Ireland, New Zealand and Australia, and the Europeans in America. The official language in these colonies was English (except in Canada, where French is also an official language).

According to regional continuity model:​​

1) homo sapiens were distributed in different parts of the world.

2) the rate of evolution was different in different regions.

3) this created difference in physical appearance

According to replacement model:

1) all the forms of older man was replaced by modern man.

2) originated in Africa.

3) changes in physical appearance due to adaptation.

Carbon is a component of all organic compounds of protoplasm like carbohydrates, lipids, proteins, nucleic acids, enzymes, hormones, etc. It constitutes 49% of dry weight of organisms and is next only to water in abundance. Carbon cycling occurs through atmosphere, ocean and through living and dead organisms. A considerable amount of carbon returns to the atmosphere as CO_2​ through respiratory activities of producers and consumers. Decomposers also contribute substantially to CO₂​ pool by their processing of waste materials and dead organic matter of land or oceans. Burning of wood, forest fire and combustion of organic matter, fossil fuels, volcanic activities are additional sources for releasing CO₂​ in the atmosphere.

The main features of the life of man in Neolithic Age are as below :
1. Discovery of the Better Tools : In this period, the man had invented more beautiful, smooth and polished tools. These tools were more useful as compared to the earlier ones.
2. Beginning of the Cultivation : In this period man had become food producer instead of food gatherer. That man developed his farming during this period. The work made him to lead a settled life ultimately.

3. Domestication  of Animals : Man started domestication of those animals that were useful to him. He started the use of animals of farming and for riding. He also started getting milk and often meat from them.

4. Invention of the Wheel : It was a great achievement of this age. The invention made the carriage and transport easier. It also helped in the making of the spinning wheel.

In February 2019, scientists reported evidence that Neanderthals walked upright much like modern humans. More laterally curved radius with a radial tuberosity placed more medially, a longer radial neck, a more ovoid radial head, and a well-developed interosseous crest. There, the Neanderthal ancestor evolved into Homo neanderthalensis some 400,000 to 500,000 years ago. The human ancestor remained in Africa, evolving into our own species—Homo sapiens. The two groups may not have cross paths again until modern humans exited Africa some 50,000 years ago.

"Homo erectus spanned a large [temporal] and geographic range," said Adam Van Arsdale, an anthropologist at Wellesley College in Massachusetts, explaining the significance of H. erectus. "It is also important because it's the first fossil ancestral to modern humans that, in many ways, shares a lot of its ecology."

In particular, H. erectus had a similar range of body sizes to modern humans, and it is the first human ancestor to have similar limb and torso proportions to those seen in modern humans. This suggests it had adapted to walking on two feet in a more open, grassland environment, rather than swinging from tree branch to branch.  

Homo habilis is regarded as the first human and the first species of the genus Homo. Homo habilis means “handy human.” Members of this species were apparently able to use tools, build shelters, and fashion protective clothing. 

Homo habilis is an archaic species of Stone Age human which lived between roughly 2.3 and 1.5 million years ago (mya), during the Early Pleistocene. The species was first discovered by anthropologists Mary and Louis Leakey at Olduvai Gorge, Tanzania in 1955, associated with the Oldowan stone tool industry.

H. habilis is considered to be intermediate between Australopithecus afarensis and H. erectus. It has been suggested reclassifying the species as Australopithecus habilis, as one of the main arguments for its classification into Homo was the now outdated idea that it was the earliest human ancestor to use stone tools. H. habilis likely used tools for butchering meat which it scavenged from more fearsome carnivores.

In 1859, Charles Darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. The concept was simple but powerful: individuals best adapted to their environments are more likely to survive and reproduce.

Darwin's theory of evolution is known as 'The Theory of Natural Selection'. It can be described as follows:
(i) Within any population there is natural variation. Some individuals have more favourable variations than others.
(ii) Even though all species produce a large number of offspring's, populations remain fairly constant naturally.
(iii) This is due to the struggle between members of the same species and different species for food, space and mate.
(iv) The struggle for survival within populations eliminates the unfit individuals. The fit individuals possessing favourable variations survive and reproduce. This is called natural selection.
(v) The individuals having favourable variations pass on these variations to their progeny from generation to generation.
(vi) These variations when accumulated over a long period of time, lead to the origin of a new species.

The sources which enable us understand the history of early humans are stone tools, fossils, etc.