Category Archives: #365papers

The Paleocene-Eocene boundary in deep ocean foraminifera – #365papers – 2017 – 65

#365papers for March 6, 2017

Thomas and Shackleton, 1996, The Paleocene-Eocene benthic forminiferal extinction and stable isotope anomalies, in Knox, Corfield, Dunay, eds., Correlation of the Early Paleogene in Northwest Europe: Geological Society Special Publication n. 101, p. 401-441.

What’s it about?

This paper examines the abundance and geochemistry of single-celled organisms called foraminiferans (forams) that were living in the oceans around 55 million years ago. Forams are still present today worldwide. They make little tiny calcite skeletons (called tests) that can be used to identify the species and then can be analyzed.

Using these foram skeletons, the authors identified the many species that lived in the ocean before and after the Paleocene-Eocene boundary and recognized some extinctions associated with the boundary. With geochemical analysis, they showed that there are some significant anomalies (rapid, unexpected changes) at the Paleocene-Eocene boundary.Continue reading “The Paleocene-Eocene boundary in deep ocean foraminifera – #365papers – 2017 – 65”

Population Structure and Cheek Swabs – #365papers – 2017 – 64

#365papers for March 5, 2017

Han and 18 others, 2017, Clustering of 770,000 genomes reveals post-colonial population structure of North America: Nature Communications.

What’s it about?

This paper uses the anonymous results from over 770 thousand AncestryDNA genomes to examine the clustering of certain genomes (ancestries) in different regions of North America. It supports empirically what we already knew: That scandinavians are all over Minnesota and North and South Dakota; that there’s an Appalachian population that was unique and isolated; and that Utahns are… special.Continue reading “Population Structure and Cheek Swabs – #365papers – 2017 – 64”

How Climate Can Drive Evolution – #365papers – 2017 – 63

#365papers for March 4, 2017

Siepielski, and 19 others, 2017, Precipitation drives global variation in natural selection: Science, v. 355, p. 959-962.

What’s it about?

The researchers here used statistical tests and models to determine which factors of climate (temperature, precipitation, and potential evapotranspiration [PET]) correlated to adaptive changes (such as changes in shape) of organisms. They looked at this for species in one area over time, and also for the same species in many areas at the same time. Continue reading “How Climate Can Drive Evolution – #365papers – 2017 – 63”

Knowing a Snail’s Diet from the Chemistry of its Shell – #3650papers – 2017 – 62

#365papers for March 3, 2017

Prendergast, Stevens, Hill, Hunt, O’Connell, and Barker, 2015, Carbon isotope signatures from land snail shells: Implications for palaeovegetation reconstruction in the eastern Mediterranean: Quaternary International, in press.

What’s it about?

This paper discusses the use of carbon isotopes in the shells of land snails to interpret what the snails were eating. To do this, they studied wild snails for which they could also measure the carbon isotopes of potential food sources.Continue reading “Knowing a Snail’s Diet from the Chemistry of its Shell – #3650papers – 2017 – 62”

The World’s Oldest Fossils? – #365papers – 2017 – 61

#365papers for February 2, 2017

Dodd, Papineau, Grenne, Slack, Rittner, Pirajno, O’Neil, and Little, 2017, Evidence for early life in Earth’s oldest hydrothermal vent precipitates: Nature, v. 543, p.60-64.

What’s it about?

This paper describes structures in a rock that lies somewhere in age between 4.28 billion years old and ~3.76 billion years old. (That’s a big range, but it’s an old rock!). The rock was almost certainly deposited in the ocean near hydrothermal activity. The structures appear to be very, very similar to those found in areas where life blossoms around deep-ocean hydrothermal vents. Continue reading “The World’s Oldest Fossils? – #365papers – 2017 – 61”

Can One Type of Animal Represent Diversity for All Members of a Community? – #365papers – 2017 – 60

#365papers for March 1, 2017

Tyler and Kowalewski, 2017, Surrogate taxa and fossils as reliable proxies for spatial biodiversity patterns in marine benthic communities: Proceedings of the Royal Society B, v. 284, 20162839.

What’s it about?

When researchers try to understand species diversity in marine systems, they often are not able to actually count all the different species present. They pick an easy-to-count group (like molluscs), and use that as a representative of the whole community. But is this legit?

Furthermore, oftentimes fossil assemblages are used for estimating diversity. But this requires only looking at species that fossilize well. Does that matter?Continue reading “Can One Type of Animal Represent Diversity for All Members of a Community? – #365papers – 2017 – 60”

Recognizing What Was Once a Safe Space Using Fossil Snails – #365papers – 2017 – 59

#365papers for February 28, 2017

Prendergast, Stevens, O’Connell, Hill, Hunt and Barker, 2016, A late Pleistocene refugium in Mediterranean North Africa? Palaeoenvironmental reconstruction from stable isotope analyses of land snail shells (Haua Fteah, Libya): Quaternary Science Reviews, v. 139, p. 94-109.

What’s it about?

There was a time in early human history when northern Africa grew arid, making life rather challenging for people. This paper is about an area where the aridity did not have such an impact, making a safe refugium for people to wait it out. The evidence that there was, in fact, a ‘safe space’ comes from isotopic analysis of fossil snails.Continue reading “Recognizing What Was Once a Safe Space Using Fossil Snails – #365papers – 2017 – 59”

Interpreting Eocene Habitat Change from Adaptive Profiles – #365papers – 2017 – 58

#365papers for February 27, 2017

Townsend, Rasmussen, Murphey, Evanoff, 2010, Middle Eocene habitat shifts in the North American western interior: A case study: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 297, p. 144-158.

What’s it about?

The middle Eocene represents the warmest times in the Earth’s last 65 or so million years. Temperatures peaked, then began to drop. There is some debate over when the drop in temperatures actually began and how it affected mid-continental environments. This study looks at mammal fossils in the Rocky Mountains of North America to find out.Continue reading “Interpreting Eocene Habitat Change from Adaptive Profiles – #365papers – 2017 – 58”

Modeling Ancient Biogeograpy from an Incomplete Fossil Record – #365papers – 2017 – 57

#365papers for February 26, 2017

Silvestro, Zizka, Bacon, Cascales-Minana, Salamin, and Antonelli, 2016, Fossil biogeography: a new model to infer dispersal, extinction and sampling from palaeontological data: Philosophical Transactions of the Royal Society B, v. 317, 20150225

What’s it about?

Biogeography is the study of the distribution of plants and animals over the Earth’s surface. Certain animals are present only in specific places, and the science of biogeography wants to know why. Fossils sometimes show that animals were once in a place where they now no longer live. Biogeography seeks to understand what happened.

In the fossil record, the study of biogeography is limited by the incomplete fossil record. This new model incorporates this problem and is able to provide insight into the past distributions of organisms and how that has changed over time.Continue reading “Modeling Ancient Biogeograpy from an Incomplete Fossil Record – #365papers – 2017 – 57”

Tempo (Rate) and Mode (Style) of Evolution Are Not Related – #365papers – 2017 – 56

#365papers for February 25, 2017

Voje, 2016, Tempo does not correlate with mode in the fossil record: Evolution, v. 70, p. 2678-2689.

What’s it about?

Tempo describes the rate of evolution. Is change happening quickly, or is it very very slow? This is distict from mode, which describes the pattern of evolution. Is there a direction to the change, all individuals growing bigger than their predecessors, for example? Is there no apparent change over time? Is there change, but it seems to be going back and forth, where sometimes descendants are bigger and sometimes they’re smaller?

This paper shows that there is no relationship between tempo and mode.Continue reading “Tempo (Rate) and Mode (Style) of Evolution Are Not Related – #365papers – 2017 – 56”