Extinct birds were nocturnal and blind. Early plants were small, unicellular or filamentous, with simple branching. “We wanted to know whether there were similar drivers for organisms during the Ediacaran period” , said Dr Emily Mitchell of Cambridge’s Department of Earth Sciences, the paper’s lead author. “So there must have been another reason life forms got so big during this period”. Many of these animals were wiped out before there were any detailed records of their behaviour or natural history. Studying fossil flowers, especially those from earlier geologic periods, is the only reliable way to get an answer to these questions.
Different types of organisms did not occupy different parts of the water column to avoid competing for resources – a process known as tiering. Scientists are discovering and describing an astonishing new world of marine microbial diversity and abundance, distribution patterns and seasonal changes. CeDAMar ( Census of the Diversity of Abyssal Marine Life ) scientists say the most abundant multi-cellular organisms are roundworms ( nematodes ), which dominate the harsh abyssal conditions in numbers, biomass and diversity. The new research shows there may be 20-50 times as many foram species as before thought, potentially undermining CLIMAP conclusions. Other causal or contributing factors to the extinction may have been the Deccan Traps and other volcanic eruptions, climate change, and sea level change. The same events happened in North And South America.
Omnivores, insectivores, and carrion-eaters survived the extinction event, perhaps because of the increased availability of their food sources. In North America, about 57 % of plant species became extinct. The ichthyosaurs had disappeared from fossil records before the mass extinction occurred. A small fraction of the Cretaceous bird species survived the impact, giving rise to today’s birds. Long-term survival past the boundary was assured as a result of filling ecological niches left empty by extinction of non-avian dinosaurs.
Thus, under the circumstances of food chain disruption before mentioned, non-avian dinosaurs died, while some crocodiles survived. The regression would also have caused climate changes, partly by disrupting winds and ocean currents and partly by reducing the Earth’s albedo and increasing global temperatures. This holds true for all time periods. But this recently unveiled 110 million-year-old fossil is the most well-preserved of the armored dinosaurs ever unearthed. This is earlier than the now accepted oldest fossil evidence would suggest. These rocks are rich in iron and a mineral called silica, which helps keep fossils. One of the most important happened at the Permian-Triassic boundary 250 million years ago. The new paper is thus nudging Archaeopteryx a step or two closer to the family tree that leads to modern birds. All Archaeopteryx fossils date back to the Late Jurassic some 150 million years ago, a time when the first bird-like dinosaurs were emerging. In a nutshell we have discovered what A. Lithographica evolved into – a more advanced bird, better adapted to flying – and we have described this as a new species of Archaeopteryx.
Animal species aren’t alone in going extinct. To find some answers, Prpic’s research team honed in on a gene called dachshund ( dac ). The researchers found that the Atapuerca individuals were relatively tall, with wide, muscular bodies and less brain mass on body mass compared to Neanderthals. The difference between this one and the previous five is that this one is the result of human activity. A few specialized species have females with no subimago, but retain the subimago stage for males. Today, many species are endangered or threatened not for natural reasons but because people have changed the habitats upon which these species depend.
The uncovering of key clues that led to the discovery that an asteroid struck the Earth 66 million years ago, triggering a mass extinction of animals, plants, and even microorganisms. And yet we ‘ll never truly get the woolly mammoth or any other extinct species back. An impact crater on the sea floor would be evidence of a possible cause of the extinction, but such a crater would by now have disappeared.
The study, published in the Journal of Geophysical Research, said that sedimentary rocks made of compacted mud or clay are the most likely to contain fossils. At that time, the planet’s surface was abundant in water, which could have supported life. The rocks are better preserved than those of the same age on Earth, researchers say.
Destruction of the ozone layer may have contributed to the largest mass extinction in the history of Earth, known as the End-Permian Extinction, a study has found. Over 95 % of marine species disappeared and, up until now, scientists have linked this extinction to a significant rise in Earth temperatures. But researchers have now discovered that this extinction took place during a short ice age which preceded the global climate warming.
Is there evidence for a direct connection between changing climate and human evolution? In the years that followed, scientists found fossils from all way of Cretaceous Period creatures buried at the site, including turtles and the oldest caiman, a kind of croc, known to science. Of course, experts say the extinction of species can not be blamed on humans alone.
