Scientists claim that walking on two legs was one of the keys to humans' development from ancient ape-like ancestors. Walking on two legs saved energy and allowed the arms to be used for activities like hunting, crafting simple tools and interacting with objects.
About seven million years ago, our early ancestors climbed trees and walked on four legs when on the ground. By five million years ago, our ancestors had developed the ability to walk on two legs but their gait was quite different from our own and their skeletons retained some features that helped them climb trees.
In the 1980s, Peter Rodman and Henry McHenry, both at the University of California, Davis, suggested that hominids evolved to walk upright in response to climate change. As forests shrank, hominid ancestors found themselves descending from the trees to walk across stretches of grassland that separated forest patches.
We aren't sure yet when exactly our ancestors began walking on two legs. Some scientists believe that Sahelanthropus tchadensis, who lived 7 million years ago, walked on two legs. Others think Orrorin tugenesis, who lived 6.1 million years ago, was able to walk bipedally.
Modern chimpanzees occasionally walk upright, but their skeletons are not adapted for regular walking on two legs. Early humans evolved skeletons that supported their bodies in an upright position. Modern humans have bodies adapted for walking and running long distances on two legs.
Scientists have long hypothesized that hominins evolved to bipedalism to save energy as they faced longer and longer treks to find food.
It's clear that early bipeds evolved when savanna grasslands became increasingly common as forests retreated 4-8 million years ago. Walking on two legs made it easier to forage and travel on the ground.
The spine curved into an S-shape helping to support the head and creating balance. Our legs grow longer, our feet get shorter and our toes lined up with one another. We lost our body hair. We developed the right muscles and the right skeletal system to facilitate walking on two legs.
Humans are the only primates who are normally biped, due to an extra curve in the spine which stabilizes the upright position, as well as shorter arms relative to the legs than is the case for the nonhuman great apes.
The findings indicate the ability to walk upright occurred in our ancestors more than 7 million years ago. What may be the earliest-known human ancestor, an ape-man called Sahelanthropus tchadensis who lived in Africa roughly 7 million years ago, walked upright for much of the time, according to a new study.
A new study suggests that an ancient genetic change helps to explain why apes and people do not have tails, but monkeys still do. A team of scientists says it may have pinpointed the genetic mutation that contributed to tail loss.
A more widely accepted theory is that, when human ancestors moved from the cool shady forests into the savannah, they developed a new method of thermoregulation. Losing all that fur made it possible for hominins to hunt during the day in the hot grasslands without overheating.
Researchers have long debated when humans starting talking to each other. Estimates range wildly, from as late as 50,000 years ago to as early as the beginning of the human genus more than 2 million years ago.
Human bipedalism – walking upright on two legs – may have evolved in trees, and not on the ground as previously thought, according to a new study involving UCL researchers.
Broadly speaking, evolution simply means the gradual change in the genetics of a population over time. From that standpoint, human beings are constantly evolving and will continue to do so long as we continue to successfully reproduce.
erectus had smaller, more primitive teeth, a smaller overall size and thinner, less robust skulls compared to later specimens. The species also had a large face compared to modern humans. Like Neanderthals, their skull was long and low, rather than rounded like our own, and their lower jaw lacked a chin.
The possible reasons for the evolution of human bipedalism include the freeing of the hands to use and carry tools, threat displays, sexual dimorphism in food gathering, and changes in climate and habitat (from jungle to savanna).
Early human ancestors stopped swinging in trees and started walking on the ground sometime between 4.2 and 3.5 million years ago, according to a new study. Early human ancestors stopped swinging in trees and started walking on the ground sometime between 4.2 million and 3.5 million years ago, according to a new study.
Lucy, a 3.2 million-year old fossil skeleton of a human ancestor, was discovered in 1974 in Hadar, Ethiopia.
The First Humans
One of the earliest known humans is Homo habilis, or “handy man,” who lived about 2.4 million to 1.4 million years ago in Eastern and Southern Africa.
"Although it's unusual that humans with UTS habitually walk on four limbs, this form of quadrupedalism resembles that of healthy adults and is thus not at all unexpected," Shapiro says.
Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years. One of the earliest defining human traits, bipedalism -- the ability to walk on two legs -- evolved over 4 million years ago.
Among the features that set humans apart from apes to make them good runners are longer legs to take longer strides, shorter forearms to enable the upper body to counterbalance the lower half during running and larger disks which allow for better shock absorption.
Four legs are good--but two legs are more energy-efficient, theorizes a researcher at the University of California at Davis. For some, walking on two legs consumes less energy than walking on all fours, according to a paper from UC Davis.
As some early humans adapted to hot climates, they evolved narrow bodies that helped them stay cool. Long legs enabled them to travel longer distances.