New Evidence Found of Early Human Ancestors Walking Upright
2021-12-06
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1Scientists are taking a second look at footprints made in ash from a volcano millions of years ago in modern-day Tanzania.
2The footprints were first found in the 1970s.
3Scientists started taking another look at them in 2019.
4 were surprised to discover that the footprints in the ash were made by two different species.
5Two sets of tracks were discovered in 1976 and 1978.
6At the time, scientists believed they were left by a human ancestor and another creature, like a bear.
7However, now the scientists believe the footprints may have been made by two different species of human ancestors.
8Ellie McNutt of Ohio University is the lead writer of the study published in Nature.
9McNutt noted the tracks are the first evidence of walking on two feet in the human fossil record.
10Jeremy DeSilva of Dartmouth College co-wrote the study.
11DeSilva said the footprints show there were different ways of walking upright at that time.
12That is because the set of footprints discovered in 1978, also from the area, show a different way of walking.
13The footprints found in 1978 have been linked with the human ancestor known as Australopithecus afarensis.
14That is the family of early humans that 'Lucy' belongs to.
15Lucy is a famous group of bones found in Ethiopia in 1974.
16Years ago, scientists did not think the footsteps found in 1976 were connected to humans because one foot crossed over the other as the being walked.
17This is called "cross-stepping," DeSilva said.
18He called it "peculiar."
19The scientists believe the being which made the newly found steps was about one meter tall.
20But they can only guess about other qualities it might have had.
21DeSilva said it is possible the steps were taken by an unknown human ancestor or it could have been one already known.
22Scientists say the ancestors of modern humans separated from chimpanzees between 6 and 7 million years ago.
23Walking on two feet was an important evolutionary step.
24So, scientists are excited by the new finding.
25Changes in the bones of the hips, spine, feet and legs permitted human ancestors to walk upright.
26This happened millions of years before modern human beings, known as homo sapiens, appeared 300,000 years ago.
27Scientists think the changes might have happened so that early humans could better see dangerous animals in the African grasslands.
28I'm Dan Friedell.
1Scientists are taking a second look at footprints made in ash from a volcano millions of years ago in modern-day Tanzania. 2The footprints were first found in the 1970s. Scientists started taking another look at them in 2019. They were surprised to discover that the footprints in the ash were made by two different species. 3Two sets of tracks were discovered in 1976 and 1978. At the time, scientists believed they were left by a human ancestor and another creature, like a bear. However, now the scientists believe the footprints may have been made by two different species of human ancestors. 4Ellie McNutt of Ohio University is the lead writer of the study published in Nature. McNutt noted the tracks are the first evidence of walking on two feet in the human fossil record. 5Jeremy DeSilva of Dartmouth College co-wrote the study. DeSilva said the footprints show there were different ways of walking upright at that time. That is because the set of footprints discovered in 1978, also from the area, show a different way of walking. The footprints found in 1978 have been linked with the human ancestor known as Australopithecus afarensis. That is the family of early humans that 'Lucy' belongs to. Lucy is a famous group of bones found in Ethiopia in 1974. 6Years ago, scientists did not think the footsteps found in 1976 were connected to humans because one foot crossed over the other as the being walked. This is called "cross-stepping," DeSilva said. He called it "peculiar." 7The scientists believe the being which made the newly found steps was about one meter tall. But they can only guess about other qualities it might have had. 8DeSilva said it is possible the steps were taken by an unknown human ancestor or it could have been one already known. 9Scientists say the ancestors of modern humans separated from chimpanzees between 6 and 7 million years ago. Walking on two feet was an important evolutionary step. So, scientists are excited by the new finding. 10Changes in the bones of the hips, spine, feet and legs permitted human ancestors to walk upright. This happened millions of years before modern human beings, known as homo sapiens, appeared 300,000 years ago. 11Scientists think the changes might have happened so that early humans could better see dangerous animals in the African grasslands. 12I'm Dan Friedell. 13Dan Friedell adapted this story for Learning English based on reporting by Reuters. Mario Ritter, Jr. was the editor. 14What do you think of the new footprint discovery? Tell us in the Comments section and visit our Facebook page. 15_________________________________________________________________ 16Words in This Story 17ash - n. the remains of something that has been burned up 18species - n. a group of animals or plants that are similar and can produce young animals or plants 19tracks - n. (pl.) a mark left on the ground by a moving animal, person, or vehicle - usually plural 20fossil - n. something (such as a leaf, bones, or a footprint) that is from a plant or animal which lived in ancient times and that has become mineralized into rock 21footprint - n. the mark left by someone's foot or shoe 22peculiar - adj. not usual or normal 23evolution - n. a theory that the differences between modern plants and animals are because of changes that happened by a natural process over a very long time