Friday coffee break

Every Friday at Nothing in Biology Makes Sense! our contributors pass around links to new scientific results, or science-y news, or videos of adorable wildlife, that they’re most likely to bring up while waiting in line for a latte.

From Sarah: Many of the biggest names in field botany are getting close to retirement, and it’s not clear who will replace their expertise.

As the star collectors disappear, botanists are debating how to fill the gap. Some researchers, including Wood, are training botanists in tropical countries, the presumed home of most undiscovered plants. But others think that it might be more efficient to recruit a large group of less-skilled collectors, aided by technology and crowdsourcing techniques. “The real question is, can we exchange a few elite collectors for an army of enthusiastic less-experienced collectors?” asks Cam Webb, a Harvard University plant scientist based in Indonesian Borneo.

From Jeremy: A new study of flowering time variation in Arabidopsis makes clever use of ecological niche modeling.

While this period of early growth has tarnished some people’s view of ENMs, it would be a shame to disregard them altogether when there are people still using them in interesting and inventive ways. A great example is Banta et al. (2012), which combines a model organism, intraspecific phenotypic variation, and spatial structure of genetic variation with ecological niche modelling. Banta et al. focus on the problematic assumption of such models that intraspecific variation in climatic tolerances is minimal or unimportant. One approach to exploring this issue more is to develop intraspecific ENMs using genotypes, rather than species, as the unit of analysis.

From Jon: Is Chagas disease “the new HIV/AIDS”?

Neglected tropical diseases (NTDs) are among the most common conditions afflicting the estimated 99 million people who live on less than US$2 per day in the Latin American and Caribbean (LAC) region [1]. Almost all of the “bottom 100 million” living in the Americas suffer from at least one NTD [1], and according to some estimates, the NTDs cause a burden of disease in the LAC region that closely approximates or even exceeds that resulting from HIV/AIDS [2]. Chagas disease (American trypanosomiasis) is a vector-borne disease and a leading cause of the deaths and disability-adjusted life years (DALYs) lost that result from NTDs in the LAC region [2]. With approximately 10 million people living with Chagas disease, this condition is one of the most common NTDs affecting the bottom 100 million in the region, a prevalence exceeded only by hookworm and other soil-transmitted helminth infections [1][2]. Moreover, among the NTDs in the Americas, Chagas disease ranks near the top in terms of annual deaths and DALYs lost [1][2]. [In-text citations sic.]

From Devin: Should be extending the Modern Synthesis? Dickins and Rahman (2012) write a very strong and clear argument against the Extened Evolutionary Synthesis as proposed by Pigliucci and colleagues.

Mass extinction: Did ancient humans get the party started 30,000 years ago?

Image

Bison priscus. The now-extinct Steppe Bison. This mummified individual, known as Blue Babe, was found in Fairbanks, AK, by a gold miner and is approximately 36,000 years old. Credit to Travis S.

During the last ice age, huge numbers of large mammals roamed the temperate zones of North America and Eurasia that lay south of vast continental glaciers. Familiar animals such as Woolly Mammoths, Woolly Rhinoceroses, Reindeer, Musk Oxen, Steppe Bison and the wild ancestors of domesticated horses along with more exotic creatures such as Glyptodon, a car-sized relative of armadillos and Megatherium, an enormous ground-dwelling sloth were abundant. With the ending of the ice age, which began around 21,000 years ago, many of these species experienced dramatic declines or went extinct. Woolly Rhinos, Mammoths, Glyptodon, and Megatherium went completely extinct, while Bison, Reindeer, Musk Oxen and wild Horse went through serious declines and range contractions.

These population declines roughly coincided with another major event in earth’s history, the global expansion of modern humans. Because of this synchronicity, there has long been debate about whether either is the cause. Did humans fuel their global expansion by hunting these animals to extinction, were they victims of a changing climate, or was it some combination of the two?

To answer this question, we need to know two main things. First, did climate change create extremely inhospitable environments for these species? Second, did the decline of these species coincide with contact with humans?

Continue reading