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
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

Turkey's Erdogan: Women Not Equal to Men

Speaking at conference in Istanbul, President Erdogan says Islam has defined a position for women: motherhood More

Ahead of SAARC Summit, Subdued Expectations

Some regional analysts say distrust between Pakistani, Indian officials has slowed SAARC's progress over the year More

Philippines Leery of Development on Reef Reclamation in S. China Sea

Chinese land reclamation projects in area have been ongoing for years, but new satellite imagery reportedly shows China’s massive construction project 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.
Aung San Suu Kyi: Myanmar Opposition to Keep Pushing for Constitutional Changei
X
November 24, 2014 10:09 PM
Myanmar opposition leader Aung San Suu Kyi says she and her supporters will continue pushing to amend a constitutional clause that bars her from running for president next year. VOA's Than Lwin Htun reports from the capital Naypyitaw in this report narrated by Colin Lovett.
Video

Video Aung San Suu Kyi: Myanmar Opposition to Keep Pushing for Constitutional Change

Myanmar opposition leader Aung San Suu Kyi says she and her supporters will continue pushing to amend a constitutional clause that bars her from running for president next year. VOA's Than Lwin Htun reports from the capital Naypyitaw in this report narrated by Colin Lovett.
Video

Video Mali Attempts to Shut Down Ebola Transmission Chain

Senegal and Nigeria were able to stop small Ebola outbreaks by closely monitoring those who had contact with the sick person and quickly isolating anyone with symptoms. Mali is now scrambling to do the same. VOA’s Anne Look reports from Mali on what the country is doing to shut down the chain of transmission.
Video

Video Ukraine Marks Anniversary of Deadly 1930s Famine

During a commemoration for millions who died of starvation in Ukraine in the early 1930s, President Petro Poroshenko lashed out at Soviet-era totalitarianism for causing the deaths and accused today’s Russian-backed rebels in the east of using similar tactics. VOA’s Daniel Shearf reports from Kyiv.
Video

Video Hong Kong Protests at a Crossroads

New public opinion polls in Hong Kong indicate declining support for pro-democracy demonstrations after weeks of street protests. VOA’s Bill Ide in Guangzhou and Pros Laput in Hong Kong spoke with protesters and observers about whether demonstrators have been too aggressive in pushing for change.
Video

Video US Immigration Relief Imminent for Mixed-Status Families

Tens of thousands of undocumented immigrants in the Washington, D.C., area may benefit from a controversial presidential order announced this week. It's not a path to citizenship, as some activists hoped. But it will allow more immigrants who arrived as children or who have citizen children, to avoid deportation and work legally. VOA's Victoria Macchi talks with one young man who benefited from an earlier presidential order, and whose parents may now benefit after years of living in fear.
Video

Video New Skateboard Defies Gravity

A futuristic dream only a couple of decades ago, the hoverboard – a skateboard that floats above the ground - has finally been made possible. While still not ready for mass production, it promises to become a cool mode of transport... at least over some surfaces. VOA’s George Putic reports.
Video

Video Falling Gas Prices Impact US Oil Extraction

With the price of oil now less than $80 a barrel, motorists throughout the United States are benefiting from gas prices below $3 a gallon. But as VOA’s Kane Farabaugh reports, the decreasing price of petroleum has a downside for the hydraulic fracturing industry in the United States.
Video

Video Tensions Build on Korean Peninsula Amid Military Drills

It has been another tense week on the Korean peninsula as Pyongyang threatened to again test nuclear weapons while the U.S. and South Korean forces held joint military exercises in a show of force. VOA’s Brian Padden reports from the Kunsan Air Base in South Korea.
Video

Video Mama Sarah Obama Honored at UN Women’s Entrepreneurship Day

President Barack Obama's step-grandmother is in the United States to raise money to build a $12 million school and hospital center in Kogelo, Kenya, the birthplace of the president's father, Barack Obama, Sr. She was honored for her decades of work to aid poor Kenyans at a Women's Entrepreneurship Day at the United Nations.
Video

Video Ebola Economic Toll Stirs W. Africa Food Security Concerns

The World Bank said Wednesday that it expects the economic impact of the Ebola outbreak on the sub-Saharan economy to cost somewhere betweenf $3 billion to $4 billion - well below a previously-outlined worst-case scenario of $32 billion. Some economists, however, paint a gloomier picture - warning that the disruption to regional markets and trading is considerable. Henry Ridgwell reports from London.
Video

Video Chaos, Abuse Defy Solution in Libya

The political and security crisis in Libya is deepening, with competing governments and, according to Amnesty International, widespread human rights violations committed with impunity. VOA’s Al Pessin reports from London.
Video

Video US Hosts Record 866,000 Foreign Students

Close to 900,000 international students are studying at American universities and colleges, more than ever before. About half of them come from Asia, mostly China. The United States hosts more foreign students than any other country in the world, and its foreign student population is steadily growing. Zlatica Hoke reports.

All About America

AppleAndroid