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

For Lebanon-based Refugees, Desperation Fuels Perilous Passage

In a war that has caused an estimated three million people to flee Syria, efforts to make perilous sea journey in search of asylum expected to increase More

South African Brewer Tackles Climate Change

Mega-brewer SAB Miller sent delegates to climate summit in Peru, says it is one of many private companies taking their own steps to fight climate change More

Indonesia Reports Increase in Citizens Joining Islamic State

Officials say more than 350 of its citizens are now in Syria or Iraq to fight with Islamic State - 50 more than last month 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.
Will Pakistan School Shooting Galvanize Pakistan Against Extremism?i
X
Ayesha Tanzeem
December 17, 2014 11:54 AM
The attack on a military school in Pakistan’s northwest city of Peshawar left 141 dead, including 132 children. Strong statements of condemnation poured in from across the world. The country announced three days of mourning, and the leadership, both political and military, promised retribution. VOA's Ayesha Tanzeem looks at how likely the Pakistani government is to clamp down on all extremist groups.
Video

Video Will Pakistan School Shooting Galvanize Pakistan Against Extremism?

The attack on a military school in Pakistan’s northwest city of Peshawar left 141 dead, including 132 children. Strong statements of condemnation poured in from across the world. The country announced three days of mourning, and the leadership, both political and military, promised retribution. VOA's Ayesha Tanzeem looks at how likely the Pakistani government is to clamp down on all extremist groups.
Video

Video ‘Anti-Islamization’ Marches Increase Tensions In Germany

Anti-immigrant rallies in Germany have been building in recent weeks, peaking Monday night in the city of Dresden where tens of thousands of people turned out to demonstrate against what they call the ‘Islamization’ of the West. Germany has offered asylum to more Syrian refugees than any other country, and this appears to have set off the protests. Henry Ridgwell reports from London.
Video

Video Aceh Rebuilt Decade After Tsunami, But Scars Remain

On December 26, 2004 there was an earthquake in the Indian Ocean so powerful it caused the Earth’s axis to wobble a few centimeters. Onshore on the island of Sumatra, the resulting tsunami was devastating. A decade later, VOA Correspondent Steve Herman reports from Banda Aceh, Indonesia, where although there is little remaining evidence of the physical devastation, the psychological scars among survivors remain.
Video

Video Refugees Living in Kenya Long for Peace in the Home Countries

Kenya is host to numerous refugees seeking safe haven from conflict. Immigrants from Somalia face challenges in their new lives in Kenya. Ahead of International Migrants Day (December 18) Lenny Ruvaga has more for VOA News from the Kenyan capital.
Video

Video Turkey's Authoritarianism Dismays Western Allies

The Turkish government has been defiant in the face of criticism at home and abroad for its raids targeting opposition media. The European Union on Monday expressed dismay after President Recep Tayyip Erdogan lashed out at Brussels for criticizing his government's action. Turkey's bid to be considered for EU membership has been on hold while critics accuse the NATO ally of increasingly authoritarian rule. Zlatica Hoke reports.
Video

Video US-China Year in Review: Hong Kong to Climate Change

The United States is pushing for a code of conduct to resolve territorial disputes in the South China Sea as it works to improve commercial ties with Beijing. VOA State Department correspondent Scott Stearns reports on a year of U.S. policy toward China from Hong Kong to climate change.
Video

Video Japanese Leader’s Election Win Raises Potential for Conflict with Neighbors

Japan’s Prime Minister Shinzo Abe and his allies easily won a two-thirds majority in parliament Sunday, even though the country has slipped into recession under his conservative policies. VOA’s Brian Padden reports from Seoul, that the prime minister’s victory will empower him to continue economic reforms but also pursue a nationalist agenda that will likely increase tensions with Japan’s neighbors.
Video

Video Nuba Mountain Families Hide in Caves to Escape Aerial Bombings

Despite ongoing peace talks between Sudan's government and the rebel Sudan People’s Liberation Movement-North, or SPLM-N, daily aerial attacks continue in South Kordofan province’s Nuba Mountains. Adam Bailes was there and reports for VOA that government forces are targeting civilian areas, rather than military positions, with their daily bombardments.

All About America

AppleAndroid