NEW DIVIDE APRIL 2016
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EVOLUTION FACTS WE SHARE 70% OF OUR GENES WITH A SLIMY
MARINE WORM! BIGGER BRAIN IS THE KEY TO SMARTER BRAIN. ARE WE STILL EVOLVING? KNOW YOUR ANSCESTRAL ROOTS
NEW DIVIDE: Evolution, April 2016
NATIONAL INSTITUTE OF FASHION TECHNOLOGY Sector-1, HSR Layout Bengaluru, Karnataka.
LAYOUT: Ananya Choudhary Fashion Communication dept. SOURCE: Live science.com Kona American Tourister Pinterest.com Freepik.com Wallpaperscraft.com Kindredcycles.com Intrawallpaper.com
NEW DIVIDE
CONTENTS APRIL 2016
9_ ARE BIG BRAINS SMARTER? 11_ MYSTERY CAVEMEN
15_ BUDDING THEORIES OF THE MONTH 17_ HUMAN GENES SIMILAR TO SLIMY MARINE WORM
18_ ANTS REGREW BRAIN
19_ MODERN BIRDS 21_ WHAT IS A HUMAN? 4_ EDITOR’S NOTE 5_ HUMAN-GORILLA SPLIT 6_ FERTILE CRESCENT?
7_ NEANDERTHAL-HUMAN LINKS
22_ NEW SPECIES
23_ GIRAFFE’S LONG NECK 25_ T-REX 27_ WHY DON’T FISH HAVE NECKS?
8_ FOOD FOR THOUGHT!
28_ EVOLUTION FACTS
Travel often. getting lost will help you find yourself.
EVOLUTION Ananya Choudhary | NIFT, Bengaluru April 9, 2016 ; 2:32 pm As a general term evolution simply refers to gradual transformation over time, but in the biological context, it is a change in the genetic material of a population of organism from one generation to the next. Though, genetic changes in every generation is very small, but it accumulates and becomes substantial changes in the population. The beginning of the earth has been a mystery, the origin of Homo sapiens not yet clear, the extinction of dinosaur is not resolved, and transformation of hominids to hominoid leading to humans is still not answerable but the solution of all these are based on the theories.The theories of evolution. Due to so many arguments the topic of creation vs. evolution has become increasingly controversial due to a precise explanation, but the validation of evolution can be done best with discovering Hominid fossils which are in major support of all the evolution assumptions, which have turned out to be true. The innumerable layers of sand, dust and rock in which fossils got trapped millions of years ago help us to establish a rough timeline which have certain amount of accuracy. Through fossil dating, there have been myriads of break through which are also approved by majority of the scientists. Another way to prove a common ancestry between species is DNA testing. We are still curious to know from which absolute point our roots spread and evolved from untamed animals to highly sophisticated humans that we are today, the line that still connects the gap between what we are and who we were.
Fossils shed new light on Human-Gorilla split. by Charles Q. Choi, Live Science Contributor | February 10, 2016 03:45pm
Fossils of what may be primitive relatives of gorillas suggest that the human and gorilla lineages split up to 10 million years ago, millions of years later than what has been recently suggested, researchers say. The Ă€QGLQJ FRXOG KHOS UHVROYH D FRQWURYHUV\ RYHU the continent where the ape and human OLQHDJHV Ă€UVW HYROYHG WKH VFLHQWLVWV DGGHG Although the fossil record of human evolution is still patchy, it is better understood than that of great apes such as chimpanzees and gorillas. Since few great ape fossils have been found in Africa so far, “some scientists have forcefully suggested that the ancestors of African apes and humans must have emerged in Eurasia,â€? said study senior author Gen Suwa, a paleoanthropologist at the University of Tokyo. To shed light on the evolution of the ape and human lineages, Suwa and his colleagues investigated the Afar rift of Ethiopia. Previous research at the Afar rift unearthed fossils of some of the earliest known hominins - that is, humans and related species dating back to the split from the ape lineages.
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Fertile Crescent? Neanderthals & Humans likely bred in the Mideast.
by Charles Q. Choi, Live Science Contributor | February 17, 2016 by Charles Q. Choi, Live Science Contributor February 17, 2016 01:14pm Neanderthals and modern humans may have interbred much earlier than thought, with ancient liaisons potentially taking place in the Middle (DVW UHVHDUFKHUV VD\ 7KLV ÀQGLQJ VXSSRUWV WKH idea that some modern humans left Africa long before the ancestors of modern Europeans and Asians migrated out of Africa, scientists added. The Neanderthals were once the closest relatives of modern humans, living in Europe and Asia until they went extinct about 40,000 years ago. Scientists recently discovered that Neanderthals and modern humans once interbred; nowadays, about 1.5 to 2.1% of DNA in people outside Africa is Neanderthal in origin. Last week, researchers reported that the genetic legacy of the 1HDQGHUWKDO KDV KDG D VXEWOH EXW VLJQLÀFDQW LPSDFW RQ PRGHUQ KXPDQ KHDOWK LQà XHQFLQJ risks for depression, heart attacks, nicotine addiction, obesity and other problems. Based on the fossil record, Neanderthals diverged from modern humans at least 430,000 years ago. Previous analysis of a Neanderthal genome from a cave in the Altai Mountains in Siberia suggests the two lineages diverged between about 550,000 to 765,000 years ago. Subsequent research suggested that interbreeding led Neanderthals to contribute genetic material to modern humans outside Africa about 47,000 to 65,000 years ago. 1RZ UHVHDUFKHUV ÀQG WKHUH PD\ KDYH DOVR EHHQ JHQH à RZ LQ WKH RSSRVLWH GLUHFWLRQ IURP PRGHUQ KXPDQV WR 1HDQGHUWKDOV 7KHVH ÀQGLQJV VXJJHVW that modern humans and Neanderthals may have met and interbred about 100,000 years ago, much earlier than thought.
´:H UDWKHU DQFLHQW VLJQDO RI JHQH à RZ IURP modern humans into the ancestors of Neanderthals from the Altai Mountains in Siberia, suggesting that early modern humans had already migrated out of Africa by the time Neanderthals from Europe moved eastward,� said study co-author Sergi Castellano, an evolutionary biologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. The scientists analyzed the genome of a Neanderthal from the Altai Mountains, as well as DNA from two other Neanderthals, one from Spain and one from Croatia. They also scanned the genomes of two modern humans, as well as one from a Denisovan, an extinct human lineage related to Neanderthals whose fossils were also discovered in the Altai Mountains. The modern human group that interbred with the Altai Neanderthals apparently later went extinct, and are not among the ancestors of present-day people outside Africa, who left that continent about 65,000 years ago, the researchers said.
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Neanderthal-Human trysts may be linked to modern Depression, Heart disease. by Charles Q. Choi, Live Science Contributor | February 11, 2016 02:14pm
Ancient trysts between Neanderthals and modern KXPDQV PD\ KDYH LQà XHQFHG modern risks for depression, heart attacks, nicotine addiction, obesity and other health problems, researchers said. The Neanderthals were once the closest relatives of modern humans. Scientists recently discovered that Neanderthals and modern humans once interbred; nowadays, about 1.5 to 2.1 percent of DNA in people outside Africa is Neanderthal in origin. 7KH UHVHDUFKHUV ÀUVW LGHQWLÀHG about 135,000 Neanderthal genetic variations found in modern humans. Next, the scientists analyzed a database of more than 28,000 adults of European ancestry from the
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Electronic Medical Records and Genomics Network, a consortium of nine hospitals across the United The data helped the researchers determine if each person had ever been treated for medical conditions such as heart disease, arthritis and depression. It also helped the scientists determine what Neanderthal genetic variants each person carried. The Neanderthal DNA that boosts the risk of nicotine addiction may have had a completely different DQG SRWHQWLDOO\ EHQHĂ€FLDO HIIHFW “that exhibited itself 50,000 years ago,â€? Capra said. Some of the VFLHQWLVWV¡ GLVFRYHULHV FRQĂ€UP previous ideas. For example, earlier research suggested that 1HDQGHUWKDO '1$ LQĂ XHQFHG VNLQ cells known as keratinocytes that help protect the skin from
environmental damage such as ultraviolet radiation and germs. 7KH QHZ ÀQGLQJV VXJJHVW WKDW Neanderthal genetic variants increase the risk of developing sun-triggered skin lesions known as keratoses, which are caused by abnormal keratinocytes. Capra and his colleagues also found that a number of Neanderthal genetic variants LQà XHQFHG WKH ULVN IRU GHSUHVVLRQ with some variants increasing the risk and others reducing it. The researchers suggest that some Neanderthal genetic variDQWV PLJKW KDYH SURYLGHG EHQHÀWV in modern human populations DV WKH\ ÀUVW PRYHG RXW RI $IULFD thousands of years ago.
Food for Thought!
Human teeth likely shrank due to tool use. by Charles Q. Choi, Live Science Contributor | February 24, 2016 01:57pm wisdom teeth may have shrunk during human evolution as part of changes that started with human tool use, according to a new study. Although modern humans are the only surviving members of the human family tree, other species once lived on Earth. However, deducing the relationships between modern humans and these extinct hominins - humans and related species dating back to the split from the chimpanzee of ancient hominins are rare. Teeth are the hominin fossils most often found because they are the hardest parts of the human body. “Teeth are central to how a fossil ancestor lived, and can tell us about which species they belonged to, how they are related to other species, what they ate, and how quickly or slowly they developed during childhood,” said lead study author Alistair Evans, an evolutionary biologist at Monash University in Melbourne, Australia. Hominin teeth have shrunk in size throughout evolution. Previous research suggested this profound shrinking in modern human wisdom tooth size was due to the advent of cooking or other changes in diet unique to modern humans. However, Evans and his colleagues now suggest this shift may have begun much earlier in human evolution.
Scientists found that hominin teeth fell into two major groups. One group was composed of the genusHomo, which includes both modern humans and extinct human relatives. The other group was made up of early hominins preceding Homo, such as the walk on two feet. In australopiths and other early hominins, the scientists found that teeth tended to get bigger toward the back of the mouth, with proportions that stayed constant regardless of the overall size of the teeth. However, in the genus Homo, the smaller all the teeth were, the smaller the teeth were toward the back of the mouth. “There seems to be a key difference between the two groups of hominins - perhaps genus Homo,” Evans said in a statement. This change in how teeth developed between genus Homo and earlier hominins may have occurred due to the advent of advanced tool use in the genus Homo, Evans said. “Tool use meant we didn’t need as big teeth and jaws as earlier hominins. This may then have increased evolutionary pressure to spend less energy developing teeth, making our teeth smaller.” In modern humans, tooth-size
reduction has reached the point where wisdom teeth are increasingly failing to develop, Evans said. “The advent of cooking made food easier to eat, meaning we didn’t need big teeth as much,” Evans said. Prior work suggested there was a lot of variation in how teeth evolved in hominins. “Now we’re seeing some very simple, clear patterns in hominin tooth evolution instead,” Evans said. These patterns could help researchers decide whether ancient hominins were members of genus Homo or not, Evans said.
Source: Boredpanda
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ARE BIG BRAINS SMARTER? by Jeanna Bryner, Live Science Managing Editor | February 03, 2016 02:33pm
Does the size of your brain say anything about your smartness? 3HUKDSV ÀWWLQJ IRU D TXHVWLRQ about the human brain — which packs in more than 100 billion neurons, according to the National Institutes of Health, but the answer is mired in complexities and unknowns. One thing scientists do agree on: A big brain alone doesn’t equate with smartness. If it did, elephants and sperm whales would win all the spelling bees. Rather, scientists look at brain mass relative to body mass in order to make any speculation about a creature’s cognitive abilities. So while an elephant noggin, at 10.5 pounds (4,780 grams), could squash a human think box in a purely physical battle of brains, you and I take the cake in a war of wits. Our brains, which weigh an average of 2.7 pounds (1,200 grams), account for about 2 percent of body weight, compared with an elephant’s under one-tenth of a percent. Studies have shown that across species relatively large brains “do seem to provide some complex cognitive skills, such as innovative solutions to ecological problems, more HIÀFLHQW UHVRXUFH PDSSLQJ DQG food acquisition, and more complex social strategies (like deception),” said Nancy Barrickman a student in Duke University’s Dept. of Biological Anthropology and Anatomy. A study by Sarah Benson, of the University of Wyoming in Laramie, and her colleagues revealed about experimental data linking animal smarts with relative brain size. In that study, detailed January 25, 2016, in the journal
proceedings of the National Academy of Sciences, the researchers gave 140 zoo dwelling mammalian carnivores, from 39 different species, a tasty problem to solve. The animals had to open an L-shaped latch to open a box and grab the treat inside. They found that animals in the bear family did best, while two species of mongoose never managed to open the latch. After accounting for other factors that could led to successful latch-opening, such as manual dexterity and sociality, the researchers concluded that relative brain VL]H ZDV WKH PRVW VLJQLÀFDQW predictor of success in the task. Differences in brain size within a species, such as humans, are relatively small, making it GLIÀFXOW WR WHDVH RXW WKH HIIHFWV of brain size and the effects of other factors. For instance, the difference in intelligence between an individual with, say, a brain that’s 1,100 grams and one that’s 1,400 grams (which could be found in humans) is confounded by other variables, including differences in density of neurons, other structural brain differences and socio-cultural factors. Take genius Albert Einstein, who’s brain was not VLJQLÀFDQWO\ ELJJHU WKDQ WKH average human’s. Rather, some scientists have found, his ability to grasp mind-boggling concepts and make seemingly impossible mental leaps may have come down to connections. Turns out, his noggin was likely highly integrated so that several paths would have connected distant regions to one another.
Mystery extinct Cavemen were more diverse than Neanderthals. by Charles Q. Choi, Live Science Contributor November 16, 2015 03:56pm A mysterious extinct branch of the human family tree that once interbred with modern humans was more genetically diverse
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WKDQ 1HDQGHUWKDOV D ÀQGLQJ that also suggests many of these early humans called Denisovans existed in what is now southern Siberia, researchers say. In 2008, VFLHQWLVWV XQHDUWKHG D ÀQJHU bone and teeth in Denisova cave in Siberia’s Altai Mountains that belonged to lost relatives now known as the Denisovans (dee-NEE-soh-vens). Analysis of '1$ H[WUDFWHG IURP D ÀQJHU ERQH from a young Denisovan girl suggested they shared a common origin withNeanderthals, but were nearly as genetically distinct from Neanderthals as Neanderthals were from living people. For instance, analysis of the Denisovan genome showed that Denisovans have contributed on
the order of 5 percent of their DNA to the genomes of present-day people in Oceania, and about 0.2 percent to the genomes of Native Americans and mainland Asians. These DNA contributions not only signify interbreeding between the two groups (scientists have yet to GHĂ€QLWLYHO\ FDOO 'HQLVRYDQV D separate species), but also may explain the origin of some traits of living humans. “In Tibet, an adaptation to live at high altitudes where there is little oxygen in the air has been shown to come from Denisovans,â€? said study co-author Svante Pääbo, an evolutionary geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
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STILL EVOLVING?
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Nom Nom! Paleo diet helped Humans evolve speech.
$PD]LQJ EOLQG FDYHÂżVK ZDONV up rocks and waterfalls.
by Charles Q. Choi, Live Science Contributor March 09, 2016 02:25pm
by Mindy Weisberger, Senior Writer March 25, 2016 02:25pm
Scientists who forced volunteers to chew raw JRDW Ă HVK \HV FKHZ KDYH IRXQG WKDW VXFK meat-gnawing likely caused human teeth and jaws to shrink throughout our evolutionary history. 6OLFLQJ UDZ Ă HVK LQWR VPDOOHU SLHFHV DQG then chewing would have helped ancient hominins spend less time and energy eating than their ancestors. These changes, in turn, might have supported the evolution of speech and language by changing human facial anatomy, scientists added. The earliest undisputed ancestor of modern humans was Homo erectus, which arose at least 1.8 million years ago. It possessed larger brains and bodies than other hominins-members of the human family tree dating from the split from chimpanzees onward.
Now, scientists have discovered a blind FDYH GZHOOLQJ ÀVK WKDW ´ZDONV¾ DURXQG LWV URFN\ KRPH VKXIà LQJ IRUZDUG E\ VKLIWLQJ its pelvis back and forth in a way that is XQLTXH DPRQJ ÀVK DOLYH WRGD\ EXW UHFDOOV adaptations that may have once allowed DQFLHQW ÀVK WR WUDQVLWLRQ IURP ZDWHU WR land, hundreds of millions of years ago. 7KLV LV WKH ÀUVW HYLGHQFH LQ D OLYLQJ DQLPDO that offers a real-time glimpse of the mechanisms that may have served as the evolutionary foundation for all the different ways that four-limbed animals glide, à \ VZLP FUHHS DQG JDOORS WRGD\ DQG throughout their evolutionary history.
Did Hobbits live alongside modern humans? by Charles Q. Choi, Live Science Contributor | March 30, 2016 02:20pm The extinct human lineage nicknamed “the hobbitâ€? for its miniature body may have vanished soon before or soon after modern humans arrived on the hobbits’ island home, rather than living alongside modern humans for thousands of years as was previously thought, researchers say. By using new techniques to date hobbit skeletons and the sediment where they were buried, researchers determined that the “hobbitâ€? species, Homo Ă RUHVLHQVLV OLNHO\ YDQLVKHG HDUOLHU WKDQ SULRU HVWLPDWHV KDG VXJJHVWHG (YHQ VR WKH VFLHQWLVWV DUHQ¡W sure whether modern humans had anything to do with the extinction of the hobbits. ´+RPR Ă RUHVLHQVLV UHPLQGV XV WKDW KXPDQ GLYHUVLW\ ZDV IDU JUHDWHU LQ WKH SDVW WKDQ LW LV WRGD\ Âľ VDLG study co-lead author Matthew Tocheri, a paleoanthropologist at Lakehead University in Ontario.
You share 70% of your Genes with this slimy marine worm! by Mindy Weisberger, Senior Writer | November 18, 2015 02:22pm People have more in common with deep-sea worms than one might suspect. Over 500 million years ago, humans and certain worms shared a common ancestor, and people still share thousands of genes with the worms, said scientists who recently sequenced genomes from two marine worm species. The results suggest humans and acorn worms, so called because of their acorn-shaped “heads,â€? are distant cousins, said the researchers, led by Oleg Simakov of the Okinawa Institute of Science and Technology Graduate University in Okinawa, Japan. The researchers analyzed genes from two acorn worm VSHFLHV 3W\FKRGHUD Ă DYD collected off Hawaii, and Saccoglossus kowalevskii, from the Atlantic Ocean. They share
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approximately 14,000 genes with humans, scientists found, comprising about 70 percent of the human genome. These genes can be traced back to an ancestor of both acorn worms and humans that lived more than 500 million years ago, during a period known as the Cambrian explosion. Genes from this ancient ancestor exist today not only in humans, but also in sea stars and their relatives, in cephalopods, and in all animals with backbones. The animals in this lineage are called “deuterostomesâ€? (pronounced DOO-teh-roe-stomes.) Species like the acorn worms can help scientists understand KRZ JHQHV WKDW Ă€UVW DSSHDUHG hundreds of millions of years ago control the development of different but related physical features across animal species. This hap-
pens even in species as different as acorn worms and humans. As deuterostomes evolved, many species emerged that were more complex than their acorn-worm cousins. But even in later species, some physical features can still be linked togenes in acorn worms for simpler structures that perform the same jobs, Simakov and his colleagues found. After sequencing the worms’ genomes and comparing them with genomic data from a range of diverse animals, scientists found 8,716 gene families, or sets of similar genes, in the acorn worms that are shared across all deuterostomes. Acorn worms feed using specialized slits near their gut regions, located between the mouth and the esophagus.
Underground Ants Regrew Brain Parts to See the Light by Mindy Weisberger, Senior Writer March 11, 2016 01:12pm About 18 million years ago, army ants that were adapted to living underground - and had lost much of their sight - returned to the surface and regrew the parts of their brains related to vision, a new study has found. %XW WKH EUDLQ EHQHÀWV GLGQ·W HQG WKHUH 1RW RQO\ GLG the ants recover a set of previously underused brain structures, but their overall brain sizeincreased as well. In turn, this brain-size increase enhanced the ants’ sensory input capabilities as well as their processing centers to handle a more complex environment. The army-ant subfamily Dorylinae dates to about 78
million years ago, and most of these ants live underground at least part of the time; their eyes are either very small or completely absent. In the study, the researchers noted that this subfamily descended from a large-eyed ancestor whose vision capabilities and vision-related brain regions dwindled over time a transition that occurred repeatedly within the ant lineage. But what happened to one branch of the army-ant family was extremely unusual: After living underground for 60 million years, army ants from the Eciton genus headed back into the light, and over time, their brains changed dramatically as they adapted to living on the surface. The researchers found that the optic lobes of VXUIDFH GZHOOLQJ (FLWRQDUP\ DQWV ZHUH VLJQLÀFDQWO\ larger than the optic lobes in their underground cousins. The regions of their brains dedicated to processing smell were larger, too, and the ants’ brain volume increased relative to their body size. These structural changes suggested to the researchers that the growth in the ants’ changing brains was being driven by a range of environmental stimuli, such as variations in activities based on the day-night cycle, an increased threat of predators and greater prey diversity.
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0RGHUQ ELUGV WRRN ÀLJKW 95 Million years ago by Laura Geggel, Staff Writer | December 11, 2015 03:30pm ET
Modern birds — from the soaring eagle to the tiny hummingbird — share a common ancestor that lived about 95 million years ago in South America, D QHZ VWXG\ Ă€QGV That feathery common ancestor laid the groundwork for its innumerable descendants. When an asteroid hit the Yucatan Peninsula about 66 million years ago, it killed off the nonavian dinosaurs. So-called modern birds in South $PHULFD VXUYLYHG DQG UDSLGO\ GLYHUVLĂ€HG WKH researchers said. These modern South American birds then moved to other parts of the world via land bridges (even Ă LHUV QHHG VWRSRYHUV RQ ODQG GLYHUVLI\LQJ GXULQJ periods of global cooling, the researchers found. [Avian Ancestors: Dinosaurs That Learned to Fly] In the new study, scientists tried to pin down the date for the most recent common ancestor of modern birds. Other studies have suggested a vast range of dates, from 72 million to 170 million years ago. “Modern birds are the most diverse group of terrestrial vertebrates in terms of species richness and global distribution, but we still don’t fully understand their large-scale evolutionary history,â€? study co-researcher Joel Cracraft, a curator in the Department of Ornithology at the American Museum of Natural History in New York City, said in a statement. (There are more than 10,000 living species of birds, compared to about 5,000 living species of mammals.) ´,W¡V D GLIĂ€FXOW SUREOHP WR VROYH EHFDXVH ZH KDYH very large gaps in the fossil record,â€? Cracraft DGGHG ´7KLV LV WKH Ă€UVW TXDQWLWDWLYH DQDO\VLV estimating where birds might have arisen, based on the best phylogenetic [family tree] hypothesis that we have today.â€? Birds began their evolutionary split from
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dinosaurs about 150 million years ago, during the Jurassic period. But these early birds had some retro features: Like dinosaurs, they still had teeth; WKH\ UHWDLQHG WKHLU ÀQJHUV VRPH ZLWK FODZV RQ WKH end of each digit; and they had long, bony tails (today’s birds usually don’t have long tails, and those that do sport tails have ones mostly made of feathers, not bone), said Daniel Ksepka, a curator of science at the Bruce Museum in Greenwich, Connecticut, who was not involved in the study. A fossil of a possible relative of early birds called Archaeopteryx (note the feather-like structures), from the Museum fßr Naturkunde in Berlin. Cracraft and his colleague used data only from modern birds, or birds without these retro features, said study co-researcher Santiago Claramunt, a research associate in the Department of Ornithology at the American Museum of Natural History. Most of the birds they examined were post-Cretaceous, living after the asteroid hit, he told Live Science. The researchers used a two-pronged approach in dating the most recent common ancestor. They looked for DNA differences among 230 bird species representative of most avian families, and used the results to construct a family tree that goes back to the most recent common ancestor. Then, they paired that data with the fossil record — 130 fossil birds in all. The resulting family tree showed that the most recent common ancestor of modern birds lived about 95 million years ago, they said.
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What is a Human? Long-standing debate surrounds our family tree. by Charles Q. Choi, Live Science Contributor December 08, 2015 08:02am Several ancient human species and relatives have been unearthed in bits and pieces over the years, including one with an orange-size brain, another dubbed the “hobbitâ€? for its miniature size and a Ă DW IDFHG KRPLQLQ ZLWK D KXJH EURZ ULGJH 7KH argument over whether groups of organisms should be lumped into a few species or split into many species is common in the study of fossils. The controversy arises because the fossil record is very SDWFK\ PDNLQJ LW GLIĂ€FXOW WR VD\ ZKHWKHU GLIIHUHQFHV among fossils are natural variations within a species or distinctions that set one species apart from another. Modern humans, Homo sapiens, are the only living members of the human lineage, or the genus Homo. Many extinct human species were thought to have walked the Earth, such as Homo habilis, which is VXVSHFWHG WR EH DPRQJ WKH Ă€UVW VWRQH WRRO PDNHUV DQG +RPR HUHFWXV WKH Ă€UVW WR UHJXODUO\ NHHS WRROV LW made. Humans and related species dating back to the split from the chimpanzee lineage are known as hominins “There is a lot of discussion among paleoanthropologists about how best to identify species in the hominin fossil record and about how many hominin species we currently have evidence for,â€? Collard said. “I know it can seem like we argue with each other about which species to assign new fossils to for the sake of it. But that’s not really the case. The DUJXPHQWV RFFXU PDLQO\ EHFDXVH RI WKH GLIĂ€FXOW\ RI the task.â€? Still, while Ian Tattersall, a paleoanthropologist at the American Museum of Natural History in New York, FDOOHG WKH Ă€QGLQJ ´ZRQGHUIXO Âľ KH VXJJHVWHG WKHVH new hominins might not belong to the Homo genus. Perhaps these new hominins are australopiths, like the famed “Lucy,â€? or even some as-yet-unknown kind
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of hominin, he said. “My hope is that people don’t jump to too many conclusions too quickly,â€? Tattersall said. (The primitive nature of H. naledi makes it more open to questions as to whether it belongs in Homo.) There are many hominin specimens that scientists regularly argue over when it comes to whether or not they are distinct species or not. For instance, some researchers consider Neanderthals a species distinct from modern humans, but others point out that Neanderthals routinely interbred with modern humans, and therefore were not another species. Australopithecus deyiremeda Another discovery earlier this year suggested there may have been more kinds of australopiths than previously thought. Many researchers have suggested that australopiths were the ancestors of Homo. In May, Yohannes Haile-Selassie, curator and head of physical anthropology at the Cleveland Museum of Natural History, and his colleagues revealed Australopithecus deyiremeda, which lived in Ethiopia 3.3 million to 3.5 million years ago. This ancient relative of humanity co-existed alongside Lucy’s species, Australopithecus afarensis, which lived about 3.4 million years ago. Scientists had long thought that there was little or no diversity among the hominins before humans HYROYHG 7KLV QHZ Ă€QGLQJ IURP +DLOH 6HODVVLH DQG KLV colleagues suggested that a diverse range of such humanlike species once lived together. “There’s no question this [Australopithecus deyiremeda] is a new species, one that adds to the luxuriance of the early hominin tree,â€? Tattersall said. However, other scientists suggest that Australopithecus deyiremedashould be lumped together with Australopithecus afarensis. “Lucy’s species just got a few more new fossils,â€? said Tim White, a paleoanthropologist at the University of California, Berkeley.
New species of giant tortoise found in the GalĂĄpagos by Laura Geggel, Staff Writer | October 21, 2015 02:00pm
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aging Charles Darwin: The island of Santa Cruz within the GalĂĄpagos has not one but two distinct species of giant tortoise, a new genetic VWXG\ Ă€QGV For years, researchers thought that the giant tortoises living on the western and eastern sides of Santa Cruz belonged to the same species. But the tortoises look slightly different, and so recently, scientists ran genetic tests on about 100 tortoises from both groups. 7KH WHVWV ZHUH GHĂ€QLWLYH 7KH WZR WRUWRLVH SRSXODWLRQV which live only about 6 miles (10 kilometers) apart on the opposite sides of the island, are actually extremely distant relatives. The Santa Cruz tortoise species that has long been called Chelonoidis porter are the ones living on the western side, in a region of the island known as La 5HVHUYD $QG QRZ WKH QHZO\ LGHQWLĂ€HG HDVWHUQ 6DQWD Cruz tortoise has been named Chelonoidis donfaustoi. It inhabits an area known as Cerro Fatal. “We immediately found that [the eastern tortoises] were very distinct from the other ones,â€? said the study’s senior author, Adalgisa Caccone, a senior ecology and evolutionary biology research scientist at Yale University. “As distinct as species from different islands.â€? In fact, the two species evolved millions of years apart.
The western tortoises are part of the oldest giant tortoise lineage in the GalĂĄpagos, which evolved about 1.74 million years ago. In contrast, the eastern tortoises are much younger — they evolved less than half a million years ago. The genetic tests showed that the eastern tortoises are more closely related to tortoises found on other GalĂĄpagos Islands than they are to the tortoises living on the western side of their own island, the researchers found. Right now, the western Santa Cruz tortoise population is booming, with about 2,000 members, whereas the eastern species has only about 250 individuals, Caccone said. Now that researchers know the eastern group is a separate species, it may receive increased habitat protection, she said. The discovery of the new species “will help these WRUWRLVHV UHFHLYH WKH VFLHQWLĂ€F DQG PDQDJHPHQW DWWHQtion they need to fully recover,â€? James Gibbs, a coauthor of the study and a conservation biologist at the SUNY College of Environmental Science and Forestry in Syracuse, said in a statement. The name of the new species honors Fausto Llerena SĂĄnchez, a GalĂĄpagos National Park ranger who spent 43 years caring for endangered tortoises in captivity.
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Here’s how the Giraffe got Its long neck. Los Angeles, 2011
GO GREEN
Evolutionary tree
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16 million years ago
Go Green Expo
The neck of the common ancestor of the okapi and the giraffe had elongated compared with its predecessors. More recently, the evolutionary tree split into two branches. The branch that results in the okapi has animals with necks that get shorter, while the giraffe branch has animals with progressively longer necks. by Karl Tate, Infographics Artist | October 07, 2015 10:55am
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HOW GIRAFFE GOT ITS LONG NECK evolutionary tree In the Okapi branch of the evolutionary tree, the vertebrae got progressively shorter.
Starting one million years ago, the vertebrae had begun elongating in the back. OKAPI (present)
GIRAFFE
SIVATHERIUM SAMOTHERIUM
By seven million years ago, samotherium vertebrae had elongated in front. CANTHUMERYX (16 million years ago)
NECKS GOT SHORTER
PRODREMOTHERIUM (25 million years ago)
NECKS GOT LONGER
Rex was likely an invasive species by Laura Geggel, Staff Writer | February 29, 2016 07:04am
“ T. rex lived from about 67 million to 65 million years ago, going extinct when a 6-mile-long (10 kilometers) asteroid slammed into Earth and killed the nonavian dinosaurs.
“
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Tyrannosaurus rex, king of the dinosaur age, wasn’t a North American native as many experts had previously thought, a new study suggests. Instead, the giant tyrannosaur was likely an invasive species from Asia that dispersed into western North America once the opportunity presented itself, paleontologists said. “It’s possible that T. rex was an immigrant species from Asia,” said study co-researcher Steve Brusatte, a paleontologist at the University of Edinburgh in necessarily a “slam dunk,” and that more research is needed to say for sure. T. rex is one of the biggest meat eaters ever to live on land, but relatively little is known about its family tree. A family tree showing 28 species in the tyrannosaur family tree, including approximately when and where they lived. Fossil evidence is lacking, but researchers suspect that the predecessors of tyrannosaurs lived on the supercontinent Pangaea, which began to break up about 200 million years ago, during the Triassic period. This would explain why tyrannosaurs fossils have been found on different continents, including Asia, western North America (called Laramidia at the time), eastern North America (Appalachia) and Europe, Carr said. As time went on, the tyrannosaurs evolved in their respective places, meaning that the tyrannosaurs in Asia grew to look different than the ones in North America. But, around 67 million years ago, the seaway between Asia and North America went down, leaving a land bridge between the two continents, Carr said. Perhaps T. rex crossed this route into North America,
Carr said. Researchers have uncovered countless T. rex fossils in western North America, but a careful analysis of T. rex’s skeletal features suggests that it is Asian in origin, the paleontologists found. In fact, T. rex is closely related to two Asian tyrannosaurs, Tarbosaurusand Zhuchengtyrannus, the researchers found. “Tarbosaurus is the Asian version of T. rex,” Brusatte told Live Science in an email. “Or, you could say that T. rex is the North American version ofTarbosaurus. They are so similar in terms of their monstrous size, their proportions, their massive jaw muscles and thick teeth and even many minutiae of their skull bones.” Asian invasion T. rex lived from about 67 million to 65 million years ago, going extinct when a 6-mile-long (10 kilometers) asteroid slammed into Earth and killed the nonavian dinosaurs. During that time, the 7-ton (6.3 metric tons) T. rex monster spread from modern-day Alberta to Texas. (A giant seaway in the middle of North America prevented T. rex from reaching the East Coast, the researchers said.) Before T. rex invaded North America, presumably from Asia, other tyrannosaurs lived in western North America, but they disappeared shortly after T. rex came onto the scene. It’s unclear why these large tyrannosaurs went extinct, but T. rex may have played a role in their demise, the researchers said. of which say that T. rex is the culmination of tens of millions of years of dinosaur evolution within North America, Brusatte said.
Source: mypage Uniserve.ca
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:K\ GRQÂśW ÂżVK have necks? by Laura Geggel, Staff Writer | April 18, 2016 10:02am
)LVK KDYH Ă€QV DQG JLOOV EXW WKH\ GRQ¡W KDYH QHFNV 7KDW¡V SDUWO\ EHFDXVH LW ZRXOG EH GLIĂ€FXOW WR VZLP quickly with a neck that wagged back and forth in the water. :KDW¡V PRUH DQ\WKLQJ FDOOHG D Ă€VK E\ GHĂ€QLWLRQ FDQ¡W KDYH D QHFN 7KH PRPHQW D Ă€VK OLNH FUHDWXUH GHYHORSHG D QHFN LW EHFDPH FODVVLĂ€HG DV DQRWKHU type of animal, experts told Live Science. The oldest neck on record belongs to Tiktaalik roseae, a creature that lived about 375 million years ago, during the Devonian period. Scientists describe T. URVHDH DV SDUW Ă€VK SDUW WHWUDSR IRXU OLPEHG DQLPDO said Ted Daeschler, the curator of paleontology at the Academy of Natural Sciences of Drexel University in 3KLODGHOSKLD ,QVWHDG RI QHFNV Ă€VK KDYH D VHULHV RI bones that connect the skull to the shoulder girdle, ZKLFK DWWDFKHV WR WKH Ă€QV 'DHVFKOHU VDLG “The shoulder girdles are those bony elements, like the clavicle and the scapula, that support the front DSSHQGDJH ZKHWKHU LW¡V D Ă€Q RU D OLPE Âľ 'DHVFKOHU
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WROG /LYH 6FLHQFH ´>,Q ÀVK@ WKH\¡UH FRQQHFWHG QRW always terribly tightly, but it’s one solid surface of bone.� 2YHU WLPH VRPH ÀVK EHJDQ WR FKDQJH VKDSH )RU LQVWDQFH WKH OREH ÀQQHG ÀVK ZKLFK LQFOXGHV WKH coelacanth - an ancient group thought to be extinct XQWLO ÀVKHUPHQ UHGLVFRYHUHG WKHP RII WKH 6RXWK African coast in 1938. According to the fossil record, WKH OREH ÀQQHG ÀVKHV RYHU WLPH ORVW WKH ERQHV WKDW connected the shoulders to the skull. Researchers consider the 9-foot-long T. roseae a OREH ÀQQHG ÀVK 'DHVFKOHU VDLG %XW LW FRPSOHWHO\ ORVW the bones that connected the skull to the shoulder girdles, and instead developed a neck. This neck likely helped it hunt in shallow, freshwater environments, he said. The earliest known neck belongs to Tiktaalik URVHDH D WUDQVLWLRQDO DQLPDO WKDW¡V SDUW ÀVK SDUW four-limbedanimal. T. roseae was discovered in 2004 in northern Canada’s Ellesmere Island.
“Its neck allowed the head to move independently from the body,â€? Daeschler said. “That’s great if you live in in shallow, swampy areas, where you might need to turn your head quickly to grab prey or to reach up to breathe.â€? ,Q FRQWUDVW ZLWKRXW D QHFN Ă€VK KDYH WR PRYH WKHLU entire bodies to aim their head in a certain direction. 2QH Ă€VK WZR Ă€VK :DV 7LNWDDOLN VWULFWO\ D Ă€VK RU D WHWUDSRG" ´,W¡V LQ WKH gray area, which is what’s so cool about evolution,â€? Daeschler said. This gray area lasted about 20 million years as that OLQHDJH HYROYHG IURP OREH Ă€QQHG Ă€VKHV WR IRXU OLPEHG amphibians, he said. Scientists call this gray area when some parts of an animal evolve, but other parts remain in their primitive forms - “mosaic evolution.â€? Animals with necks had a unique advantage; they could quickly steer their mouth without having to move their entire bodies. In fact, “all of these early tetrapods were predators, no doubt about it,â€?
Daeschler said. %XW PDQ\ Ă€VK DUH SUHGDWRUV WRR DQG WKH\ KDYH EHHQ very successful without necks, he said. Moreover, whales and dolphins are thought to have once lived on land before they moved back into the water. Once they became marine animals again, whales and dolphins greatly shortened their neck vertebrae, so that the entire neck is short and rigid instead of being ORQJ DQG Ă H[LEOH ´7KH LGHD WKHUH ZDV WKDW ORQJ DQG Ă H[LEOH QHFNV DUH not great if you’rejetting though the water,â€? Daeschler said. “Your head gets thrown to the side by the pressure. It’s better not to have a neck and just be a torpedo and swim forward.â€?
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EVOLUTION FACTS!
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1. IT TOOK 100,000 YEARS FOR THE WORLD POPULATION TO REACH 1 BILLION. HOWEVER, IT ONLY TOOK 133 YEARS FOR THAT NUMBER TO DOUBLE TO 2 BILLION AND 44 YEARS TO REACH 4 BILLION. 2. OUR BRAINS HAVE SHRUNK OVER THE LAST 30,000 YEARS, LOSING A TENNIS BALL IN SIZE. 3. THE PLANTARIS MUSCLE, THE MUSCLE THAT ALLOWS US TO GRIP STUFF JUST LIKE OTHER PRIMATES, IS MISSING IN 9% OF THE POPULATION. 4. A NEW SPECIES IS ACHIEVED WHEN TWO POPULATIONS OF THE SAME LIVING THING BECOME SO DIFFERENT THAT THEY CAN NO LONGER BREED WITH EACH OTHER. 5. ALL HUMANS DEVELOP A TAIL IN THE WOMB THAT EVENTUALLY DISSOLVES. 6. A HOBBIT-LIKE SPECIES OF HUMAN LIVED ABOUT 18,000 YEARS AGO. ABOUT THE SIZE OF A 3-YEAR-OLD, THEY LIVED WITH PYGMY ELEPHANTS AND 10-FOOT-LONG LIZARDS. 7. BIRDS EVOLVED FROM DINOSAURS AND BOTH ARE DESCENDED FROM REPTILES. THE CLOSEST LIVING REPTILIAN RELATION OF A BIRD IS THE CROCODILE.
8. SOME SNAKES HAVE HIPBONES, WHICH SHOWS THEY ONCE HAD FOUR LEGS LIKE LIZARDS, THEIR CLOSE COUSINS.
ยดย ย ย FISH GILLS AND MAKES AMPHIBIANS GULP AIR HAS BEEN IMPERFECTLY REWIRED IN MAMMALS. IT CAN MAKE THE DIAPHRAGM GO INTO SPASMS, WHICH CAUSES HICCUPS. 10. EVOLUTIONARY BIOLOGISTS NOTE THAT A SYMMETRICAL FACE IS MORE ATTRACTIVE AROUND THE WORLD BECAUSE SYMMETRY SIGNALS GOOD GENES FOR REPRODUCTIVE HEALTH.
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GO WHEREVER IT TAKES YOU.