How long ago did humans arise

This marks the earliest known instance of human groups mating with each other—something we know happened a lot more later on. After the superarchaic humans came the archaic ones: Neanderthals, Denisovans and other human groups that no longer exist.

Since then, researchers have discovered Neanderthals and Denisovans not only mated with each other, they also mated with modern humans. Rogers , a professor of anthropology and biology at the University of Utah and lead author of the Science Advances paper. As a more recently-discovered group, we have far less information on Denisovans than Neanderthals. But archaeologists have found evidence that they lived and mated with Neanderthals in Siberia for around , years.

The most direct evidence of this is the recent discovery of a year-old girl who lived in that cave about 90, years ago. DNA analysis revealed that her mother was a Neanderthal and her father was a Denisovan. The human lineage of Australopithecus afarensis, Homo habilis, Homo erectus, Neanderthals and Homo sapiens. Scientists are still figuring out when all this inter-group mating took place.

The appearance of a slow and steady buildup may just be a consequence of the quirks of preservation. Organic materials like wood often decompose without a trace, so some signs of behavior may be too ephemeral to find.

Complex lifestyles might not have been needed early on in the history of Homo sapiens , even if humans were capable of sophisticated thinking. Sally McBrearty, an archaeologist at the University of Connecticut in Storrs, points out in the book Rethinking the Human Revolution that certain developments might have been spurred by the need to find additional resources as populations expanded. Hunting and gathering new types of food, such as blue duikers, required new technologies.

Some see a slow progression in the accumulation of knowledge, while others see modern behavior evolving in fits and starts. He notes that several tool technologies and aspects of symbolic expression, such as pigments and engraved artifacts, seem to disappear after 70, years ago.

The timing coincides with a global cold spell that made Africa drier. Populations probably dwindled and fragmented in response to the climate change. Innovations might have been lost in a prehistoric version of the Dark Ages. Perhaps the best way to settle whether the buildup of modern behavior was steady or punctuated is to find more archaeological sites to fill in the gaps.

There are only a handful of sites, for example, that cover the beginning of human history. Erin Wayman writes Smithsonian. Erin Wayman is a science and human evolution blogger for Hominid Hunting. She has M. As in biological anthropology and science writing. Cave art evolved in Europe 40, years ago. Archaeologists reasoned the art was a sign that humans could use symbols to represent their world and themselves.

The beginnings of agriculture and the rise of the first civilizations occurred within the past 12, years. Paleoanthropology is the scientific study of human evolution. Paleoanthropology is a subfield of anthropology, the study of human culture, society, and biology.

The field involves an understanding of the similarities and differences between humans and other species in their genes, body form, physiology, and behavior.

Paleoanthropologists search for the roots of human physical traits and behavior. They seek to discover how evolution has shaped the potentials, tendencies, and limitations of all people.

For many people, paleoanthropology is an exciting scientific field because it investigates the origin, over millions of years, of the universal and defining traits of our species. However, some people find the concept of human evolution troubling because it can seem not to fit with religious and other traditional beliefs about how people, other living things, and the world came to be.

Nevertheless, many people have come to reconcile their beliefs with the scientific evidence. Early human fossils and archeological remains offer the most important clues about this ancient past. These remains include bones, tools and any other evidence such as footprints, evidence of hearths, or butchery marks on animal bones left by earlier people. Usually, the remains were buried and preserved naturally. They are then found either on the surface exposed by rain, rivers, and wind erosion or by digging in the ground.

By studying fossilized bones, scientists learn about the physical appearance of earlier humans and how it changed. Bone size, shape, and markings left by muscles tell us how those predecessors moved around, held tools, and how the size of their brains changed over a long time. Archeological evidence refers to the things earlier people made and the places where scientists find them. By studying this type of evidence, archeologists can understand how early humans made and used tools and lived in their environments.

The process of evolution involves a series of natural changes that cause species populations of different organisms to arise, adapt to the environment, and become extinct. All species or organisms have originated through the process of biological evolution. In animals that reproduce sexually, including humans, the term species refers to a group whose adult members regularly interbreed, resulting in fertile offspring -- that is, offspring themselves capable of reproducing.

Scientists classify each species with a unique, two-part scientific name. In this system, modern humans are classified as Homo sapiens.