September 30, 2019

Last month, in late August, scientists published a description of a 3.8-million-year-old fossil skull, allowing people to gaze into the face of perhaps our earliest ancestor, Australopithecus anamensis. According to one researcher, the remarkable fossil is the most complete skull of the “oldest-known species” of the human evolutionary tree. The important fossil helps define the ancient human evolutionary family, but it also brings more questions to the often cloudy relationships among that family’s members.

Paleontologists discovered the near-complete skull of Australopithecus anamensis in Ethiopia in 2016. Credit: © Dale Omori, Cleveland Museum of Natural History

A. anamensis belongs to the hominin group of living things that includes human beings and early humanlike ancestors. A team of paleontologists led by Yohannes Haile-Selassie from the Cleveland Museum of Natural History found the hominin skull in 2016 at a site called Woranso-Mille in the Afar region of Ethiopia. The fossil, officially known as MRD-VP-1/1 (MRD for short), was discovered in two halves that fit together, making up a nearly complete skull. The skull’s position in volcanic sediments enabled scientists to determine its age—3.8 million years—with great precision. The anatomical features of the skull helped identify it as A. anamensis, one of the earliest known hominin species. This species was first identified from a handful of fossil skull fragments and other bones discovered at Lake Turkana in northern Kenya in the 1990’s. Those specimens are between 4.2 million and 3.9 million years old.

Scientists used the fossilized Australopithecus anamensis skull to create this image of one of humankind’s earliest ancestors. Credit: © John Gurche/Matt Crow, Cleveland Museum of Natural History

The MRD skull shows that A. anamensis had a small brain, a bit smaller than that of a modern chimpanzee. The skull more closely resembles an ape than a modern human, with a large jaw and prominent cheekbones, but the canine teeth are much smaller and more humanlike. And, like humans, A. anamensis walked upright on two legs. Sediments and other fossils show that the region where the skull was found was arid, but the ancient creature died in a vegetated area near a small stream that entered a lake.

The site in Ethiopia where MRD was discovered is not far from the village of Hadar, where fossils of another early hominin, Australopithecus afarensis, were first discovered in 1974. A. afarensis is known mainly from the partial skeleton of an adult female, the famous “Lucy,” found in deposits dating to about 3.2 million years ago. Other A. afarensis fossils date to nearly 3.8 million years ago, which suggests Lucy and her kind may have coexisted with A. anamensis.

Most scientists, however, think that Lucy and her kind evolved from A. anamensis, and that the transition occurred as one species disappeared and the other took over. Scientists now understand that A. anamensis could still be ancestral to Lucy, but that other A. anamensis populations continued to thrive unchanged as her neighbors. The prehistoric landscape of East Africa had many hills, steep valleys, volcanoes, lava flows, and rifts that could easily have isolated populations over many generations. Over time, the populations eventually diverged. Scientists think that one of these species eventually gave rise to Homo, the human genus.

August 5, 2019

Last week, on July 29, in the northeastern African nation of Ethiopia, citizens worked with conservation groups, business leaders, and the government to plant more than 350 million trees in a single day. Part of Ethiopia’s Green Legacy Initiative to combat deforestation and climate change, the highly organized event resulted in the planting of 353,633,660 seedlings in just 12 hours. Believed to be a world record, the number far exceeded the original goal of planting 200 million trees in one day. The Green Legacy Initiative hopes to brighten the ecological future of a nation prone to such climate-related problems as drought, famine, and soil erosion.

Prime Minister Abiy Ahmed plants one of more than 350 million trees planted in Ethiopia on July 29, 2019. Credit: Office of the Prime Minister

For the record tree-planting day, many schools and government offices were closed to allow more people to participate. Ethiopian Prime Minister Abiy Ahmed joined in the effort, planting trees in the capital city of Addis Ababa. The tree-planting drive targeted areas that have been stripped of forests over the years, and the types of new trees varied from region to region. The United Nations estimates that just 4 percent of Ethiopia is currently covered by forest, down from about 30 percent in 1900. Ethiopia’s ever-growing population, the need for more farmland, unsustainable forest use, and climate change are cited as the major causes for the nation’s drastic deforestation.

Illinois Senator (and future United States President) Barack Obama plants a tree in Uhuru Park in Nairobi, Kenya, with environmental activist and Nobel Peace Prize winner Wangari Muta Maathai in 2006. Every tree planted helps counteract the effects of climate change. Credit: © Green Belt Movement

The Green Legacy Initiative, launched in May 2019, aims to help reverse Ethiopia’s environmental decline by providing tree seedlings, encouraging tree-planting groups, and asking every citizen to plant at least 40 trees by the end of October. (The seedlings have a better chance of surviving in Ethiopia during the wetter months from May to October.) With a population of about 114 million people, this puts the initiative’s goal at more than 4 billion newly planted trees. More than 2.6 billion trees have been planted so far. Aside from ordinary counting methods, the Ethiopian government is using satellites and special computer software to keep track of the immense number of planted seedlings. The Green Legacy Initiative is also cleaning waterways and making agriculture more sustainable.

The planting of carbon dioxide-absorbing trees—along with recycling and reducing the use of plastics, fossil fuels, and other environmentally damaging materials—is a highly effective way to counteract the effects of global warming and climate change. India set the previous world record for the most trees planted in one day (50 million) on July 11, 2016.

July 27, 2015

Last Friday, July 24, U.S. President Barack Obama arrived in his father’s homeland of Kenya. It is the first visit to Kenya by a serving president of the United States, but it is not Obama’s first visit. He traveled to Kenya as a law student in 1998.

U.S. President Barack Obama is seen as a child with his Kenyan father in an undated family snapshot from the 1960′s. Credit: Reuters/Landov

On his first night in Kenya, Obama attended a dinner with family members on his father’s side. On Saturday, he met with Kenyan President Uhuru Kenyatta, son of Jomo Kenyatta, the first leader of independent Kenya. Presidents Uhuru Kenyatta and Obama discussed economic and business issues, as well as Islamic extremism in Africa. The Islamic militant group al-Shabab has been active and has launched a number of attacks in Kenya. Obama also discussed human rights issues in Kenya.

On Sunday, Obama spoke at a sports arena. His speech encouraged Kenya, but it also touched on things about Kenya that need to change in order for Kenya to move forward. Some of the issues Obama focused on were corruption, rights for LGBT (lesbian, gay, bisexual, or transgender) people, and women’s rights. About women, Obama stated,  “Treating women and girls as second-class citizens, those are bad traditions,” he said. “They need to change. They’re holding you back.”

President Obama left Kenya for Ethiopia on Sunday. Today, Monday the 27th, he meets with African leaders to try to encourage South Sudan to accept an agreement to end the violence in that country. Since 2013, a civil war in South Sudan has killed thousands of people.

Other World Book articles:

• Gay rights movement
• Terrorism
• Women’s movement

June 10, 2015

Fossilized jaws and teeth discovered in northern Ethiopia belong to a previously unknown ancient human ancestor that lived 3.3 million years ago, according to scientists who announced the discovery in late May 2015 in the journal Nature. The new species, named Australopithecus deyiremeda by the scientists who described the fossil remains, lived at the same time and in the same region as another early human ancestor.

Yohannes Haile-Selassie, a paleoanthropologist at the Cleveland Museum of Natural History, holds casts of the jaws of Australopithecus deyiremeda, a new human ancestor species from Ethiopia. (Credit: Laura Dempsey, Cleveland Museum of Natural History)

The Ethiopian anthropologist Yohannes Haile-Selassie of the Cleveland Museum of Natural History in Ohio described the fossils, which were found at a site in the Afar region of northeastern Ethiopia. The scientists concluded that the fossils are from an early hominin. Hominins, also called hominids, are the scientific family that includes human beings and early humanlike ancestors. The site is about the same age and only a few miles from Hadar, where fossils of Australopithecus afarensis were first discovered by the anthropologist Donald C. Johanson in 1974.  A. afarensis was an early humanlike creature known in part from a famous fossil skeleton nicknamed “Lucy.” The two species are similar in their anatomy, but they can be distinguished by different shaped jaws. Haile-Selassie believes the fossil jaws and teeth belong to the same species as several fossil foot bones that were discovered at a nearby site in Ethiopia and described in 2012.

The scientists believe the fossils demonstrate that Lucy and her kind were only one of perhaps several hominin species that inhabited the forests and grasslands of East Africa more than 3 million years ago. Each species was adapted to a different habitat and likely had different anatomy and behavior, including how it moved around. However, scientists are not certain if any of these species are direct ancestors to modern humans.

Paleoanthropologists speculate that the distinct jaw shapes of A. deyiremeda and A. afarensis could mean that they used their teeth on different kinds of food. This means that the two species could have lived side-by-side, because they would not have directly competed for food, shelter, and territory. However, not all scientists agree that these new fossils represent a new species of hominin. Some scientists think that the fossils simply demonstrate that physical variation was great among A. afarenis.

Other World Book articles:

• Anthropology (1973-a Back in time article)
• Anthropology (1983-a Back in time article)
• Anthropology (2012-a Back in time article)

March 7, 2014

Warmer temperatures, associated with global warming, are causing malaria to become more common at higher altitudes, according to a report in the latest issue of the journal Science. A study of malaria in the highlands of Africa and South America by an international team of scientists found that generally higher temperatures in the future may well lead to millions of additional people exposed to the mosquito-borne disease.

Malaria, a disease common in tropical and subtropical regions, is caused by infection with parasites called Plasmodia. The parasites are one-celled organisms called protozoans. They are transmitted to human beings through the bite of the female Anopheles mosquito.

“The impact in terms of increasing the risk of exposure to disease is very large,” stated the lead author of the study, Mercedes Pascual of the University of Michigan. Pascual noted that in the past, higher altitudes provided  protection against this devastating disease because both the malaria parasite and the mosquito that carries it do not thrive in cooler air.

Malaria parasites appear in pink and blue in a false-color image. (c) CNRI/SPL from Photo Researchers

Pascual and her team studied densely populated areas in the highlands of Colombia and Ethiopia, where scientists have kept detailed records of both temperature and malaria cases from the 1990’s to 2005. The team found that malaria shifted higher into the mountains in warmer years and stayed at lower elevations in cooler years. “We have estimated that, based on the distribution of malaria with altitude, a 1-Celsius-degree (1.8-Fahrenheit-degree) rise in temperature could lead to an additional 3 million cases in people under 15 years old,” stated Pascual. Climatologists predict that Earth’s surface temperature could rise by as much as 1 Celsius degree by 2030.

The World Health Organization estimates that there were about 207 million cases of malaria in 2012 leading to approximately 627,000 deaths. Children living in Africa are particularly hard hit by the disease.

Additional World Book articles:

• Charles Louis Alphonse Laveran
• Sir Ronald Ross
• Blood Feeders: Real-Life Vampires (a Special Report)
• The Timeless Scourge of Malaria (a Special Report)