The giant panda’s false thumb
Researchers discovered fossils from an extinct panda that helped scientists understand the evolution of the false thumb
Text pochází z agentury Reuters. |
Fossils unearthed in China are helping scientists get a better grasp on one of the marvels of evolution: the giant panda’s false thumb, which helps this veggie-loving bear munch the bamboo that makes up most of its diet.
Researchers recently said that they discovered near the city of Zhaotong in northern Yunnan Province fossils about 6 million years old of an extinct panda called Ailurarctos that bore the oldest-known evidence of this improvised extra digit - actually a greatly enlarged wrist bone called the radial sesamoid.
It closely resembled the false thumb of modern pandas, but is a bit longer and lacks the inward hook present on the end in the extant species that provides even greater ability to manipulate bamboo stalks, shoots and roots while eating.
The false thumb is an evolutionary adaptation to augment the existing five actual digits of the panda’s hand.
A bear’s hand lacks the opposable thumb possessed by humans and various primates that enables the grasping and handling of objects using the fingers. The false thumb serves a similar function.
Slovíčkafossil zkamenělina, fosilie unearth sth vykopat, odhalit co get a better grasp lépe pochopit marvel zázrak, div false thumb falešný palec munch žvýkat, chroupat extinct vyhynulý, vymizelý digit prst (form.) greatly enlarged značně zvětšený wrist bone zápěstní kost resemble sth podobat se čemu inward hook vnitřní háček extant species dosud žijící druhy bamboo stalk stonek bambusu shoot výhonek augment sth rozšířit co opposable thumb protilehlý palec possess sth mít, vlastnit enable umožnit grasp uchopit (pevně), sevřít co crude primitivní hooked zahnutý less-protruded tip méně vyčnívající špička bended hook ohnutý háček tight grip pevné sevření, úchop jerking action škubání bite-size chunk menší kousek precise správný, přesný minor bone drobná kost |
„It uses the false thumb as a very crude opposable thumb to grasp bamboos, sort of like our own thumbs except it is located at the wrist and is much shorter than human thumbs,“ said Natural History Museum of Los Angeles County paleontologist Xiaoming Wang, lead author of the research published in the journal Scientific Reports.
„The hooked false thumb offers a tighter grasp of the bamboo and, at the same time, its less-protruded tip - because of the bended hook - makes it easier for the panda to walk. Think of the false thumb as being stepped on every time the panda walks. And therefore, we think it is the reason that the false thumb in modern pandas has become shorter, not longer,“ Wang said.
The panda’s tight grip on bamboo acts against the jerking action of the mouth in order to quickly break food into bite-size chunks, Wang added. „One of the most important features of human beings and their primate relatives is the evolution of a thumb that can be held against other fingers for precise grasping. The panda’s false thumb is far less effective than the human thumb, but it is enough to provide the giant panda with the grasping ability to eat bamboo,“ said paleontologist and study co-author Tao Deng of the Chinese Academy of Sciences in Beijing.
The false thumb was not present in another closely related bear that lived about 9 million years ago, the researchers said.
„This is a great innovation - transformation of a minor bone into an element that is useful for a particular purpose,“ said Harvard University paleobiologist and study co-author Lawrence Flynn.
NAUČTE SE GRAMATIKUV dnešním článku jsme narazili na spojkuwhile, ve větě: „… to manipulate bamboo stalks, shoots and roots while eating.“ While (= zatímco, když, během) používáme v časových větách, často před větami v minulém průběhovém čase, např. „The phone rang while I was doing the dishes.“ While se používá i v kontrastních větách (ve významu přestože, i když), např. „While your design is excellent, it isn’t suitable for our purposes.“ Vedlejší věty se v angličtině zejména v písemném stylu často zkracují pomocí -ing, např. „I damaged the car while trying to park it.“ Přeložte (řešení na konci článku): 1. Během hlídání dětí poslouchala podcasty. 2. I když se zdá, že falešný palec pandy je méně efektivní, pomáhá jí jíst bambus. 3. Začalo pršet, když jsem běhal. |
Lekci připravila Englishka.cz
Řešení: 1. While watching the kids, she was listening to podcasts. 2. While panda’s false thumb seems to be less effective, it helps it to eat bamboo. 3. It started raining / to rain while I was jogging.
