News / Science & Technology

Climate Changes Appear to Coincide with Human Evolution Milestones

U.S. National Research Council calls for more exploration

Rick Potts has led excavations at early human sites in the East African Rift Valley, and currently directs a multidisciplinary research team at the famous handaxe site of Olorgesailie, Kenya.
Rick Potts has led excavations at early human sites in the East African Rift Valley, and currently directs a multidisciplinary research team at the famous handaxe site of Olorgesailie, Kenya.

Multimedia

Audio
TEXT SIZE - +
Rosanne Skirble

Rick Potts tackles the mysteries of human origins for a living.

For over 25 years, the paleo-anthropologist at the Smithsonian Institution in Washington has led expeditions to East Africa to explore how our early ancestors adapted to changes in landscape and climate.

"You walk up a hillside of this eroded region of southern Kenya and you see layer after layer that indicates a huge lake was here, but then the lake is gone," says Potts. "Then there's a volcanic eruption that covered over all the grass. Animals had to move away. Then there's a river that came through that area. The lake is back and then there's a big drought, on and on, layer after layer — amazing chapters in this story of climate change."

Climate and evolution

Potts says prehistoric climate changes appear to have coincided with milestones in human evolution, such as the emergence of bipedalism — walking on two feet — the development of a larger brain and tool-making skills.   

"What we were able to investigate is how those tool makers, using stone hand-axes for hundreds of thousands of years were able to adjust. But then the environmental changes got ramped up, and the hand axes disappear, and we see the technologies that are smaller," he says. "We have stone points that were attached to arrows that allowed our direct ancestors, right before the emergence of our own species, to hunt animals and do many more diverse things."

Multipurpose tools used to chop wood, butcher animals, and make other tools -- dominated early human technology for more than a million years.
Multipurpose tools used to chop wood, butcher animals, and make other tools -- dominated early human technology for more than a million years.

Search for answers

That link between climate and human evolution is the subject of a new National Research Council study.  

Andrew Hill is professor of anthropology at Yale University and part of the team of scientists that contributed to the report. He says efforts to better understand the link between climate and evolution — and to more clearly define those evolutionary adaptations — are limited by gaps in the fossil record.

"Any time you find something, it's likely that there's some before that you haven't found yet, and so you're not really dating the origin of these things precisely," says Hill. "That gets better if you find more stuff. The bigger the size, the more likely you are to have an accurate first-appearance of a new behavior. And that's where we are deficient at the moment and why we need to explore more."

Climate and fossil records suggest that some events in human evolution coincided with substantial changes in African and Eurasian climate according to a new report published by the National Research Council.
Climate and fossil records suggest that some events in human evolution coincided with substantial changes in African and Eurasian climate according to a new report published by the National Research Council.

High-tech exploration

Hill says the research team recommends a major new effort to locate additional sites. And he notes that remote-sensing devices aboard satellites and unmanned aircraft can help to more precisely target where to excavate.

"You can actually search for different types of rock because different types of rock give off different types of signal in the non-visible part of the spectrum. And so you can look for sedimentary rocks as opposed to volcanic rocks and different kinds of rocks like lake beds where there might be something plausible."    

Hill says the NRC report also recommends more extensive drilling to extract sediment cores from dry land, lake beds and ocean floors in regions where humans evolved. "In doing that you are also finding more specimens of other kinds of animals and archeology."

And, Hill adds, computer-generated climate models using data on temperature, precipitation and vegetation near human fossils can be a huge help not only in reconstructing past environments, but in understanding the science of climate change in our own era.  "A very concrete way in which it's useful is that when you are working out models for what will happen in the future, the only way in which you can really test it, is by applying the models to the past where you know what really happened from other signals."

Family tree


Over at the Museum of Natural History in Washington Rick Potts is curator of a new exhibit on human origins.

He is also a contributor to the NRC report, which he says recommends new education programs to build on already-strong public interest in the science of human origins.  

"The idea of being able to trace the emergence of our own species' resilience as the last remaining member of a diverse family tree, and how that evolutionary history interacts with the possibilities of the future, I think are extremely relevant, bringing together these two enormous areas of public curiosity, climate change and human evolution."

Potts says fossil and climate records can bring us a little closer to answering two fundamental questions: What does it mean to be human? And how will our resilient species adapt to a future of changing climate?

You May Like

Multimedia Anti-Keystone XL Protests Continue

Demonstrators are worried about pipeline's effect on climate change, their traditional way of life, health and safety More

Thailand's Political Power Struggle Continues

Court gave Prime Minister Yingluck Shinawatra until May 2 to prepare her defense over abuse of power charges but uncertainty remains over election timing More

Malaysia Plane Search Tests Limits of Ocean Mapping Technology

Expert tells VOA existing equipment’s maximum operating depth is around 6 kilometers as operation continues on ocean bed for any trace of MH370 More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Pet Kangaroo Helps Spread Environmental Messagei
X
Penelope Poulou
April 22, 2014 5:53 PM
Children’s author Julia Heckathorn travels the world to learn about different ecosystems and endangered animals. She pours her knowledge into children’s books, hoping the next generation will right the environmental wrongs of our times. As in many children's books, the main character in Heckathorn's stories is an animal. Unlike those other characters, though, this one is real - a kangaroo, that lives in the author’s backyard. VOA’s Penelope Poulou has more.
Video

Video Pet Kangaroo Helps Spread Environmental Message

Children’s author Julia Heckathorn travels the world to learn about different ecosystems and endangered animals. She pours her knowledge into children’s books, hoping the next generation will right the environmental wrongs of our times. As in many children's books, the main character in Heckathorn's stories is an animal. Unlike those other characters, though, this one is real - a kangaroo, that lives in the author’s backyard. VOA’s Penelope Poulou has more.
Video

Video Pro-Russian Separatists Plan 'Federalization Referendum' in Eastern Ukraine

Pro-Russian separatists in eastern Ukraine say they plan to move forward next month with a referendum vote for greater autonomy, despite the Geneva agreement reached with Russia, the U.S. and Ukraine to end the political conflict. VOA's Brian Padden reports from the city of Donetsk in Eastern Ukraine.
Video

Video Pope Francis Hopes Dual Canonizations Will Reconcile Church

On April 27, two popes - John the XXIII and John Paul II - will be made saints in a ceremony at St. Peter’s Square. VOA religion correspondent Jerome Socolovsky says the dual canonization is part of the current pope’s program to reconcile liberals and conservatives in the Roman Catholic Church.
Video

Video In Capturing Nature's Majesty, Film Makes Case for Its Survival

French filmmaker Luc Jacquet won worldwide acclaim for his 2005 Academy Award-winning documentary "March of the Penguins". Now Jacquet is back with a new film that takes movie-goers deep into the heart of a tropical rainforest - not only to celebrate its grandeur, but to make the case for its survival. VOA's Rosanne Skirble reports.
Video

Video Boston Marathon Bittersweet for Many Runners

Monday's running of the Boston Marathon was bittersweet for many of the 36,000 participants as they finished the run that was interrupted by a double bombing last year. Many gathered along the route paid respect to the four people killed as a result of two bombings near the finish line. VOA's Carolyn Presutti returned to Boston this year to follow two runners, forever changed because of the crimes.
Video

Video International Students Learn Film Production in World's Movie Capital

Hollywood - which is part of Los Angeles - is the movie capital of the world, and many aspiring filmmakers go there in hopes of breaking into the movie business. Mike O'Sullivan reports that regional universities are also a magnet for students who hope to become producers or directors.
Video

Video Pacific Rim Trade Deal Proves Elusive

With the U.S.-led war in Iraq ended and American military involvement in Afghanistan winding down, President Barack Obama has sought to pivot the country's foreign policy focus towards Asia. One aspect of that pivot is the negotiation of a free-trade agreement among 12 Pacific Rim nations. But as Obama leaves this week on a trip to four Asian countries he has found it very difficult to complete the trade pact. VOA's Ken Bredemeier has more from Washington.
Video

Video Autistic Adults Face Housing, Job Challenges

Many parents of children with disabilities fear for the future of their adult child. It can be difficult to find services to help adults with disabilities - physical, mental or emotional - find work or live on their own. The mother of an autistic boy set up a foundation to advocate for the estimated 1.2 million American adults with autism, a developmental disorder that causes communication difficulties and often social difficulties. VOA's Faiza Elmasry reports.
AppleAndroid