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1、關(guān)于科普類英語文章閱讀人類祖先露西因何而死lucy, the most famous fossil of a human ancestor, probably died after falling from a tree, according to a study appearing in nature led by researchers at the university of texas at austin.lucy, a 3. 18-mi1lion-year-old specimen of australopithecus afarensis - or southern ape of
2、afar” - is among the oldest, most complete skeletons of any adult, erectalking human ancestor.since her discovery in the afar region of ethiopia in 1974 by arizona state universityanthropologist donald johanson and graduate student tom gray, lucy - a terrestrial biped - has been atthe center of a vi
3、gorous debate about whether this ancient species also spent time in the trees.“it is ironic that the fossil at the center of a debate about the role of arboreal ism in human evolution likely died from injuries suffered from a fall out of a tree,“ said lead author johnkappelman, a ut austin anthropol
4、ogy and geological sciences professor.kappelman first studied lucy during her u. s. museum tour in 2021, when the fossil detouredto the high-resolution x-ray computed tomography facility utct in the ut jackson school ofgeosciences - a machine designed to scan through materials as solid as a rock and
5、 at a higher resolution than medical ct. for 10 days, kappelman and geological sciences professor richardketcham carefully scanned all of her 40-percent-complete skeleton to create a digital archive of more than 35,000 ct slices.“l(fā)ucy is precious. there* s only one lucy, and you want to study her as
6、 much as possible,ketcham said. ct is nondestructive. so you can see what is inside, the internal details andarrangement of the internal bones.studying lucy and her scans, kappelman noticed something unusual: the end of the right humerus was fractured in a manner not normally seen in fossils, preser
7、ving a series of sharp, cleanbreaks with tiny bone fragments and slivers still in place.“this compressive fracture results when the hand hits the ground during a fall, impacting the elements of the shoulder against one another to create a unique signature on the humerus, saidkappelman, who consulted
8、 dr. stephen pearce, an orthopedic surgeon at austin bone andjoint clinic, using a modern human-scale, 3d printed model of lucy.pearce confirmed: the injury was consistent with a four-part proximal humerus fracture, caused by a fall from considerable height when the conscious victim stretched out an
9、 arm in an attempt to break the fall.古生物學(xué)家發(fā)現(xiàn)大型礪王龍化石paleontologists with the burke museum of natural history and culture and the university of washington have discovered a tyrannosaurus rex, including a very complete skull. the find, whichpaleontologists estimate to be about 20 percent of the animal,
10、 includes vertebrae, ribs,hips and lower jaw bones. the team, led by burke museum adjunct curator of vertebrate paleontology and uwbiology professor gregory p. wilson, discovered the t. rex during an expedition to the hell creek formation in northern montana - an area that is world-famous for its fo
11、ssil dinosaur sites.two burke museum paleontology volunteers, jason love and luke tufts, initially discovered pieces of fossilized bone protruding from a rocky hillside. the bones large size and honeycomb-likestructure indicated they belonged to a carnivorous dinosaur. upon further excavation, the t
12、eam discovered the t. rex skull along with ribs, vertebrae, and parts of the jaw and pelvis.t. rex was one of the largest meat-eating dinosaurs to ever roam the earth. measuring an average of 40-feet long and 15 to 20-feet tall, t. rex was a fierce predator with serrated teeth andlarge jaws. fossil
13、evidence shows it ate other dinosaurs like edmontosaurus and triceratops, with crushed bones from the animals even showing up in the its fossilized poop. t. rex lived about66-68 million years ago in forested river valleys in western north america during the late cretaceous period.the t. rex found by
14、 the burke/uw team is nicknamed the tufts-love rex, in honor of the two volunteers who discovered it. the skull is about 4 feet longweighs about 2,500 pounds in itsprotective plaster jacket. excavation in the field revealed the right side of the skull from base to snout, including teeth. burke paleo
15、ntologists believe it is very probable the other side ofthe skull is present, but will need to carefully remove the rock surrounding the fossil before they can determine its completeness.we think the tufts-love rex is going to be an iconic specimen for the burke museum and the state of washington an
16、d will be a must-see for dinosaur researchers as well, “ said wilson.非洲草原上的大象數(shù)量大幅下降paul g. allen* s vulcan inc. today announced the results of the $7 million, three-year great elephant census gec 一 , the first-ever pan-african survey of savanna elephants using standardized data collection and valida
17、tionmethods. managed by elephants without borders ewb, the immense projects report confirms substantial declines in elephantnumbers over just the last decade. the researchers report that the current rate of species decline is 8 percent per year, primarily due to poaching. the pan-african survey show
18、s the estimatedsavannah elephant population to be 352,271 within the 18 countries surveyed to-date, representing at least 93 percent of savannah elephants in these countries. for savannah elephant populationsin 15 of the gec countries, for which repeat counts were available, populations declined by
19、30 percent between 2021 and 2021. 84 percent of the population surveyed was sighted in legallyprotected areas compared to 16 percent in unprotected areas. however, large numbers of carcasses were observed in many protected areas indicating that elephants are struggling both within andoutside of park
20、s. experts say the ivory trade and poaching pose serious threats and there is now a risk that savannah elephants could disappear from parts of africa. the scientific report ofthe gec findings was published on august 31, in the peer-reviewed open access journal peerj and is freely accessible atthe gec team used the most accurate, up-to-date counting and statistical methods toanalyze data, accurately determining the number and distribution of the great majority of african savannaelephants and this now provides a baseline on a continental scale for futu
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