The results, reported in Nature Communications , indicate that our early human ancestors, including the famous fossil ‘Lucy’ (a species known as Australopithecus afarensis), may have been able to use their torsos to increase walking efficiency in the same way as modern humans.
The torso (the part of the body that includes the ribcage, belly and pelvis) of chimpanzees has long been thought to be a rigid block, best suited for a life of tree climbing. Humans, on the other hand, have long and flexible torsos that aid in walking by allowing us to rotate our upper body in the opposite direction of our lower body. The findings from the paper, titled “Surprising trunk rotational capabilities in chimpanzees and implications for bipedal walking proficiency in early humans,” changes the evolutionary view of how early human ancestors walked and what they were able to do.
“During walking, we actually observed as much rotation within the torsos of chimpanzees as in humans,” said Nathan Thompson, lead author and a PhD student in the Department of Anatomical Sciences at Stony Brook University. “This means that the widely accepted assumptions in the scientific community about how the chimpanzee torso works based on the skeleton alone are incorrect. Our results also point to the notion that a limitation to upright walking that we thought affected Lucy and other early human ancestors probably was not a limitation at all.”
The research team used high-speed cameras to track and compare how the torsos of humans and chimpanzees actually moved during bipedal walking. They studied the movements by way of three-dimensional kinematic analyses and computer-generated comparisons.
They discovered that the main difference between human and chimpanzee bipedalism is that chimps swing their hips much more.
“Only when our early ancestors were able to reduce this hip rotation were their upper bodies able to play a human-like role in promoting efficient bipedal walking,” said Thompson. “When this actual transition occurred is still an open question.”
There is a continuing debate about how the hips of our ancestors worked compared to ours.
“For instance, depending on who you ask, the 3.2 million-year-old Lucy fossil either rotated her pelvis exactly like modern humans or up to 2.5 times more,” he explained.
Given this uncertainty, the research team modeled the transition from a more chimp-like pattern of the upper body movement to that of a more human-like pattern. They found that even if Lucy rotated her pelvis 50 percent more than modern humans, her upper body would have functioned essentially like ours. This means that even as early as 3.2 million years ago Lucy might have been able to save work and energy in much the same way as humans do today.
“As we get a better idea of how our closest living relatives move, we are able to learn much more about the isolated piles of early human bones that the fossil record leaves us,” added Thompson. “Only then can we paint a complete picture of how we evolved into what we are today.”
Co-authors on the paper include Susan Larson, Brigitte Demes, and Nicholas Holowka of Stony Brook University, and Matthew C. O’Neill of the University of Arizona.
The vessel, procured by the Natural Environment Research Council for UK science is the latest in marine technology.
Starting in the spring of 2014 just as the plankton blooms got underway, more than 100 researchers have tracked the take-up of carbon and nutrients by plankton and food webs. Through the year, later expeditions would follow the subsequent recycling of dead plankton material into detritus and gases – for some material – a journey to the deep ocean where it can remain for eons.
Dr Phil Williamson, the programme’s science coordinator said:
“The Shelf Seas Biogeochemistry programme has been the most comprehensive study ever of the physical, chemical and biological processes in UK waters from the sea surface to the sea floor. This research will improve understanding of the key processes affecting marine ecosystems, how they may be affected by climate change and more direct human activities such as seafloor disturbance or overfishing.”
Photosynthetic life in the oceans provides around half of the world’s oxygen and also removes carbon dioxide from the atmosphere. Oxygen is released as the carbon goes into making plants – phytoplankton, which is eaten by zooplankton. These two types of plankton are the building blocks of the marine food web. A proportion of dead material even makes its way to the ocean floor fueling life there.
Dr Henry Ruhl of the National Oceanography Centre said: “A key question for the final leg of the journey in the plankton life cycle is: how much of it makes its way to the seafloor and how is it processed?
“Marine snow is a carbon-rich mix of decaying phytoplankton matter, dead microscopic animals and their poo. We are keen to know how – and how much of that material gets from the shelf seas into the deep ocean. This is where the carbon can be locked up for decades or thousands of years.”
The field phase of the research ended this summer with an expedition by RRS Discovery over the Continental Slope between Cornwall and southern Ireland led by Dr Ruhl’s team used robot subs, landers and underwater gliders and other tools to measure the processing and transport of material between relatively shallow shelf seas, which are less than 200 metres deep, and the Atlantic, which in this part of the ocean reaches depths of 4000 metres.
The National Oceanography Centre’s deep diving robot sub, Autosub6000 carried out photographic surveys of the seafloor to determine the abundance of different marine species and their role in food webs and natural recycling processes.
The Shelf Seas Biogeochemistry programme is jointly funded by the Natural Environment Research Council (NERC) and the Department for Environment, Food and Rural Affairs (Defra). Other researchers in the UK and Europe have also been involved in providing complementary data through the year, widening the scope of the study.
The programme is divided into five work packages led by oceanographers around the UK. Each package involves a multidisciplinary, multi-institute team and the overall programmatic framework maximizes scientific linkages and interacations between more than a dozen research institutes
– The study of water column processes is led by Prof Jonathan Sharples, University of Liverpool;
– Seafloor processes by Prof Martin Solan, University of Southampton;
– Iron exchanges by Prof Peter Statham, University of Southampton;
– Process modelling by Professor Icarus Allen, Plymouth Marine Laboratory;
– Shelf sea carbon budgets – blue carbon – by Keith Weston, Cefas Lowestoft.
This has been the fieldwork phase of the programme; over the coming months the researchers will analyse the data and samples collected from the expeditions.
Most of the work was conducted in the Celtic Sea collecting data and samples that will be analysed over the coming months.
The Autosub will be on RRS Discovery when she arrives in London on 7th October as part of an event to mark the anniversary of NERC’s 50 Years of Science. Discovery will be moored alongside HMS Belfast in the Thames until 11th October.
The only logical source for that oxygen is the earliest known example of photosynthesis by living organisms, say University of Wisconsin-Madison geoscientists.
“Rock from 3.4 billion years ago showed that the ocean contained basically no free oxygen,” says Clark Johnson, professor of geoscience at UW-Madison and a member of the NASA Astrobiology Institute. “Recent work has shown a small rise in oxygen at 3 billion years. The rocks we studied are 3.23 billion years old, and quite well preserved, and we believe they show definite signs for oxygen in the oceans much earlier than previous discoveries.”
The most reasonable candidate for liberating the oxygen found in the iron oxide is cyanobacteria, primitive photosynthetic organisms that lived in the ancient ocean. The earliest evidence for life now dates back 3.5 billion years, so oxygenic photosynthesis could have evolved relatively soon after life itself.
Until recently, the conventional wisdom in geology held that oxygen was rare until the “great oxygenation event,” 2.4 to 2.2 billion years ago.
The rocks under study, called jasper, made of iron oxide and quartz, show regular striations caused by composition changes in the sediment that formed them. To detect oxygen, the UW-Madison scientists measured iron isotopes with a sophisticated mass spectrometer, hoping to determine how much oxygen was needed to form the iron oxides.
“Iron oxides contained in the fine-grained, deep sediment that formed below the level of wave disturbance formed in the water with very little oxygen,” says first author Aaron Satkoski, an assistant scientist in the Geoscience Department. But the grainier rock that formed from shallow, wave-stirred sediment looks rusty, and contains iron oxide that required much more oxygen to form.
The visual evidence was supported by measurements of iron isotopes, Satkoski said.
The study was funded by NASA and published in Earth and Planetary Science Letters.
The samples, provided by University of Johannesburg collaborator Nicolas Beukes, were native to a geologically stable region in eastern South Africa.
Because the samples came from a single drill core, the scientists cannot prove that photosynthesis was widespread at the time, but once it evolved, it probably spread. “There was evolutionary pressure to develop oxygenic photosynthesis,” says Johnson. “Once you make cellular machinery that is complicated enough to do that, your energy supply is inexhaustible. You only need sun, water and carbon dioxide to live.”
Other organisms developed forms of photosynthesis that did not liberate oxygen, but they relied on minerals dissolved in hot groundwater — a far less abundant source than ocean water, Johnson adds. And although oxygen was definitely present in the shallow ocean 3.2 billion years ago, the concentration was only estimated at about 0.1 percent of that found in today’s oceans.
Confirmation of the iron results came from studies of uranium and its decay products in the samples, says co-author Brian Beard, a senior scientist at UW-Madison. “Uranium is only soluble in the oxidized form, so the uranium in the sediment had to contain oxygen when the rock solidified.”
Measurements of lead formed from the radioactive decay of uranium showed that the uranium entered the rock sample 3.2 billion years ago. “This was an independent check that the uranium wasn’t added recently. It’s as old as the rock; it’s original material,” Beard says.
“We are trying to define the age when oxygenic photosynthesis by bacteria started happening,” he says. “Cyanobacteria could live in shallow water, doing photosynthesis, generating oxygen, but oxygen was not necessarily in the atmosphere or the deep ocean.”
However, photosynthesis was a nifty trick, and sooner or later it started to spread, Johnson says. “Once life gets oxygenic photosynthesis, the sky is the limit. There is no reason to expect that it would not go everywhere.”
A new study of fossil cervical vertebrae reveals the evolution likely occurred in several stages as one of the animal’s neck vertebrae stretched first toward the head and then toward the tail a few million years later. The study’s authors say the research shows, for the first time, the specifics of the evolutionary transformation in extinct species within the giraffe family.
“It’s interesting to note that that the lengthening was not consistent,” said Nikos Solounias, a giraffe anatomy expert and paleontologist at NYIT College of Osteopathic Medicine. “First, only the front portion of the C3 vertebra lengthened in one group of species. The second stage was the elongation of the back portion of the C3 neck vertebra. The modern giraffe is the only species that underwent both stages, which is why it has a remarkably long neck.”
The study, which includes a computational tracking model of the evolutionary elongation, is published in Royal Society Open Science. See: http://rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.150393
Solounias and Melinda Danowitz, a medical student in the school’s Academic Medicine Scholars program, studied 71 fossils of nine extinct and two living species in the giraffe family. The bones, discovered in the late 1800s and early 1900s, were housed at museums around the world, including those in England, Austria, Germany, Sweden, Kenya, and Greece.
“We also found that the most primitive giraffe already started off with a slightly elongated neck,” said Danowitz. “The lengthening started before the giraffe family was even created 16 million years ago.”
But the main discovery came after the researchers analyzed anatomical features of the various fossils and compared them to the evolutionary tree.
“That’s when we saw the stages playing out,” said Danowitz.
Solounias and Danowitz found the cranial end of the vertebra stretched initially around 7 million years ago in the species known as Samotherium, an extinct relative of today’s modern giraffe. That was followed by a second stage of elongation on the back or caudal portion around one million years ago. The C3 vertebra of today’s giraffe is nine times longer than its width — about as long as an adult human’s humerus bone, which stretches from the shoulder to the elbow.
As the modern day giraffe’s neck was getting longer, the neck of another member of the giraffe family was shortening. The okapi, found in central Africa, is the only other living member of the giraffe family. Yet, rather than evolving a long neck, Danowitz said this species is one of four with a “secondarily shortened neck,” placing it on a different evolutionary pathway.
The researchers next study area is the evolution of the giraffe’s long leg bones.
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