How old is the first humans

A planetoid colliding with Earth, analogous to but larger and slower-moving a potential impact It kicked up a layer of dust that settled all over the world, a layer that can be found today in our planet's sedimentary rock. On the older side of that layer, fossils such as dinosaurs, pterosaurs, ichthyosaurs and plesiosaurs are abundant. Giant reptiles, ammonites, and large classes of plants and animals all existed prior to that event, along with small, flying birds and the tiny, land-dwelling mammals.

After that event, the mammals survived. With no larger predators to stop them, they grew, diversified, and experienced a population explosion. Primates, rodents, lagomorphs, and other forms of mammals, including placental mammals, marsupials, and even the egg-laying mammals are all abundant at the start of the Cenezoic epoch.

A duck-billed platypus Ornithorhynchus anatinus swims in the Tyenna River in Mt. Field National Despite the fact that it lays eggs, has a bill, and has a myriad of features we don't typically associate with mammals, the duck-billed platypus is more closely related to us than it is to any extant bird or reptile.

Almost immediately, the primates began diversifying even further. With its enormous eyes, it was uniquely well-adapted to see at night. With its enormous eyes but a dry nose, the tarsier holds the distinction as the first haplorrhine to Note that they have dry, rather than wet, noses. The niche it now occupied was sufficiently different from the remaining groups of our ancestors that they evolved differently from the rest of their cousins from this point onwards.

This type of evolutionary splitting occurs every so often, and isn't unique to primates. Although we normally don't think very much about our distant cousins and how they develop once they've split off from us, it isn't just haplorrhines like us and our direct ancestors that underwent interesting phases of evolution.

All throughout the past 65 million years — just as it was before that time — the various mammals, birds, plants, and other living organisms evolved together. Evolution is driven by environmental changes, and that includes all the floral and faunal changes that occur on our planet.

A reconstructed illustration of the protocetid Georgiacetus vogtlensis, a primitive whale-like This transformation left many large, unfilled niches in the ocean, paving the way for cetaceans the large oceanic mammals to develop. The artiodactyls may have all evolved from a single, common ancestor, or may have evolved independently. Animals like Indohyus, which dates to 48 million years ago, may have given rise to protocetids: shallow-water mammals that returned to land to give birth.

The early fossilized remains of Darwinius Masilae, known as "Ida," was originally thought by many to Although it dates back to 47 million years ago, it is probably more closely related to a lemur than it is to a human.

Right around that time, 47 million years ago, the primate Darwinius masillae existed, as the fossil Ida, preserved from that time, provides a spectacular example. Although this was originally touted as a proverbial "missing link" in human evolution, Ida is not a haplorrhine like us, but a strepsirrhene: a wet-nosed primate. But another 7 million years later — 40 million years ago — an important development occurred among the dry-nosed primates: the New World monkeys branched off.

Humans and our ape ancestors are descended from Old World monkeys; New World monkeys are the first simians or higher primates to evolutionary diverge from our lineage. They would go on to colonize most of South America, where they are still found in abundance today. The golden-headed lion tamarin is an example of a New World monkey. A computer reconstruction of a skull belonging to the species Homo habilis , which has been published in Nature journal, indicates that it may well have been the evolutionary descendant of the species announced today.

The researcher involved, Prof Fred Spoor of University College London told BBC News that, taken together, the new findings had lifted a veil on a key period in the evolution of our species.

The dating of the jawbone might help answer one of the key questions in human evolution. What caused some primitive ancestors to climb down from the trees and make their homes on the ground. A separate study in Science hints that a change in climate might have been a factor. An analysis of the fossilised plant and animal life in the area suggests that what had once been lush forest had become dry grassland. As the trees made way for vast plains, ancient human-like primates found a way of exploiting the new environmental niche, developing bigger brains and becoming less reliant on having big jaws and teeth by using tools.

He says the new species clearly does show the earliest step toward human characteristics, but suggests that half a jawbone is not enough to tell just how human it was and does not provide enough evidence to suggest that it was this line that led to us. He notes that the emergence of human-like characteristics was not unique to Ethiopia.

This would suggest several different species of humans co-existing in Africa around two million years ago with only one of them surviving and eventually evolving into our species, Homo sapiens. It is as if nature was experimenting with different versions of the same evolutionary configuration until one succeeded.

Prof Stringer added: "These new studies leave us with an even more complex picture of early humans than we thought, and they challenge us to consider the very definition of what it is to be human.

We cooperate to wage war and help each other. We teach, tell stories, trade. We have morals, laws. The details of our tools, fashions, families, morals and mythologies vary from tribe to tribe and culture to culture, but all living humans show these behaviours. That suggests these behaviours — or at least, the capacity for them — are innate. These shared behaviours unite all people.

We inherited our humanity from peoples in southern Africa , years ago. Archaeology and biology may seem to disagree, but they actually tell different parts of the human story. Bones and DNA tell us about brain evolution, our hardware.

Tools reflect brainpower, but also culture, our hardware and software. Humans in ancient times lacked smartphones and spaceflight, but we know from studying philosophers such as Buddha and Aristotle that they were just as clever.

That creates a puzzle. If Pleistocene hunter-gatherers were as smart as us, why did culture remain so primitive for so long? Why did we need hundreds of millennia to invent bows, sewing needles, boats? And what changed? Probably several things. First, we journeyed out of Africa , occupying more of the planet. There were then simply more humans to invent, increasing the odds of a prehistoric Steve Jobs or Leonardo da Vinci.

We also faced new environments in the Middle East, the Arctic, India, Indonesia, with unique climates, foods and dangers, including other human species. Survival demanded innovation.

Many of these new lands were far more habitable than the Kalahari or the Congo. Climates were milder, but Homo sapiens also left behind African diseases and parasites.