Introduction to Human Evolution | The Smithsonian Institution's Human Origins Program
category of mamals including lemurs, monkeys, apes, and humans . best evidence of an evolutionary relationship between two organisms according to evolutionary theory, which best describes the first living organisms from which all life. In this lesson we'll be exploring the relationship between humans and extant door in phylogeny, or the study of evolutionary relationships between species. The comparatively minor anatomical differences between humans and apes are A number of changes in our bodies were related to the evolution of this form of In reality, this difference is not as great as it would initially seem because the.
Physical and genetic similarities show that the modern human speciesHomo sapiens, has a very close relationship to another group of primate species, the apes. Humans first evolved in Africa, and much of human evolution occurred on that continent.
The fossils of early humans who lived between 6 and 2 million years ago come entirely from Africa. Most scientists currently recognize some 15 to 20 different species of early humans. Scientists do not all agree, however, about how these species are related or which ones simply died out. Many early human species -- certainly the majority of them — left no living descendants. Scientists also debate over how to identify and classify particular species of early humans, and about what factors influenced the evolution and extinction of each species.The Evolution From Ape To Man - Full Documentary
Early humans first migrated out of Africa into Asia probably between 2 million and 1. They entered Europe somewhat later, between 1. Species of modern humans populated many parts of the world much later. For instance, people first came to Australia probably within the past 60, years and to the Americas within the past 30, years or so.
The beginnings of agriculture and the rise of the first civilizations occurred within the past 12, years. Paleoanthropology Paleoanthropology is the scientific study of human evolution.
- Introduction to 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.
The Gap Between Humans and Apes
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. David Pilbeam of Harvard University argued that Ramapithecus, a 14 million year old ape from the Siwalik Mountains of Pakistan, but also found in East Africa, was the earliest member of the human line.
It was even suggested that humans had split from a common ancestor with the African apes by about 30 million years ago, making our evolution a very long process indeed.
Genetics | The Smithsonian Institution's Human Origins Program
Coincidentally, at the time Ramapithecus was being touted as the first human ancestor, pioneers of the nascent field of molecular biology were beginning to compare blood proteins among different mammals, including humans and apes, to study their evolution.
Their findings were poised to cause a major upset among anthropologists, and would come to set the framework for understanding the origins of the human branch until today. Emile Zuckerkandl and twice Nobel Prize winner Linus Pauling were among the many workers studying haemoglobin, and were interested in differences between humans and the gorilla.
The neutrality of these mutations meant they could be used as a yardstick of evolutionary distance - the more mutations accumulated, the longer the time since the species split. Although the molecular clock is now a well established tool in evolutionary biology, it is not without its controversies or detractors.
With the advent of ancient DNA sequencing, we can even study clocks in extinct species and get a handle on whether its ticking rate has changed over time. These first molecular clocks suggested humans and gorillas had separated only around 11 million years ago, not 30 million as suggested by fossils like Ramapithecus.
Surprisingly, this date is remarkably similar to even the most recent molecular clock estimates as well as the latest fossil discoveries, as we shall see later, indicating gorillas diverged between 8.
Incidentally, once the bony face of Ramapithecus was unearthed from the fosil record of Pakistan in the early s, the human status of this ape was quickly reassessed. When it comes to studying Great Ape evolution, especially chimpanzees, we have so little to go on from the fossil record that we have no choice but reply heavily on genomic evidence.
As it turns out, everything we know about chimp evolution has been garnered from their genomes: Pan troglodytes had its genome sequenced inwhile the bonobo species: Pan paniscus only had its genetic code fully read in But, for a good portion of the twentieth century, the precise branching arrangements of the African ape tree - whether humans were closest to either of the apes or sat out on our own - were contested.
Following the sequencing of the complete human and chimpanzee genomes bygeneticists showed that we share around 99 percent of our DNA, firming up our closeness. Inalong came Orrorin tugenensis and Sahelanthropus tchadensisfossils that appeared to belong to the human line, and dated between 6 and 7 million years old. Most molecular clocks at the time, and many since, put the split between humans and chimpanzees at only around million years ago.