Taxonomy term

paleoecology

Free swimmers came back first after Great Dying

About 252 million years ago, at the boundary between the Permian and Triassic periods, the vast majority of marine and terrestrial life died out in the most devastating extinction event in Earth’s history. Earth’s ecosystems eventually recovered, but not in the way — or as quickly as — scientists thought. In a new study looking at how marine species reemerged in the Triassic, researchers report a surprising trend of recovery from the top of the food chain down.

14 Feb 2019

Hammerhead herbivore pioneered vegetarianism in Triassic seas

New fossils found in southern China hint that the earliest herbivorous marine reptiles got off to a bizarre start: Atopodentatus unicus, which lived about 244 million years ago and sported a unique hammerhead-like snout for grazing underwater plants, sheds light on how the earliest marine reptiles began experimenting with herbivory after the Permian mass extinction, which killed off 96 percent of marine organisms about 252 million years ago. This “Great Dying” event left vast holes in the ecology of the Early Triassic, and a diversity of new feeding styles evolved to occupy the open niches.

 
21 Sep 2016

Owl pellets bridge ancient and modern ecosystems

In Homestead Cave near Utah’s Great Salt Lake, owls have been regurgitating pellets containing the undigested bones and hair of prey — typically small mammals like rodents — at a relatively constant rate since the end of the Pleistocene glaciations about 13,000 years ago. Those pellets have stacked up and fossilized in the cave to present a near-continuous glimpse into how mammal communities in this part of the Great Basin region have changed over time. Now, paleontologists examining bones in the pellets have found that, although small mammals in the region have generally been able to adapt to shifting ecosystems in the past, today, in the face of landscape-altering human activity, the mammal population is changing in unprecedented ways.
25 Oct 2015

Bigger is better in the sea

Since first appearing in the fossil record more than 550 million years ago, complex animals have steadily grown in average size, from millimeters to meters to many meters in length. This tendency of species to evolve toward larger sizes over time — known as Cope’s rule — has been studied before in individual species, such as horses and clams, but a new dataset of thousands of marine animals is giving scientists their first large-scale look at how Cope’s rule applies to whole ecosystems over hundreds of millions of years.
 
28 Jun 2015

Tiny plant fossils offer big view of ancient ecosystems

A key part in understanding a terrestrial ecosystem is analyzing its vegetation structure: How dense is the foliage? Is its canopy open or closed? How much sunlight reaches the ground? Answering these questions about a modern plant community is relatively easy, but for paleoecosystems, such analysis has not been possible until recently. Now, a new study published in Science reports a novel way to create what lead author Regan Dunn calls a “3-D look” at ancient ecosystems.
13 Jun 2015

Ancient food web shows modern structure

All animals have to eat, but who eats whom or what is often difficult for ecologists to discern in modern habitats, let alone in extinct ecosystems. Now a new study focusing on an exceptional assemblage of 48-million-year-old fossils in Germany has pieced together one of the most complex food webs ever constructed, and the results show this ancient ecosystem was strikingly similar to today’s food webs.

11 Jul 2014

Arctic megafauna thrived on pollen-poor plants

Ancient changes in vegetation have traditionally been studied based on fossil pollen; however, this record tends to be biased toward plants that produce lots of pollen, such as grasses, reeds and sedges. Now, researchers have sequenced plant DNA retrieved from radiocarbon-dated permafrost samples and gained further insight into the Arctic plant communities not readily identifiable by pollen analysis.
 

24 Jun 2014

Hydrological models locate ancient human migration routes

Archaeologists and geologists have long hypothesized that major river systems flowed north through the Sahara Desert about 100,000 years ago. These rivers would have provided a sort of network of “green corridors” across the Sahara that early humans could have traversed as they migrated out of Africa. Ancient lake records, fossil river systems, and radioisotope data have offered evidence for the existence of flowing water in the region.

01 Nov 2013

CSI La Brea: Tiny traces reveal big secrets of the tar pits

The La Brea tar pits in the middle of Los Angeles are known for turning up spectacularly preserved specimens of dire wolves, saber-tooth cats and woolly mammoths. But how long it took for the animals to sink down into the sticky tar after they became trapped has long been a mystery. Now a new study looking at the traces left by hungry bone-eating insects is providing a minimum time span for burial, as well as confirming some long-held suspicions about when the tar pits were at their most lethal.

27 Oct 2013

No pre-Columbian deforestation of the western Amazon

Relying primarily on clues in soil cores, a research team has unearthed evidence that pre-Columbian western Amazonian people did not significantly disturb or alter interfluvial forests, contrary to previous suggestions.

18 Jun 2012

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