Yet, I do think it’s a reality of the ways in which science

August 27, 2013


Declaring The Discovery Of A New Species Can Get Tricky

moncler sale May was an exciting moncler jacket online month for new discoveries that add to our knowledge of human evolution during the period around 3 million years ago. This is before the origin of the genus Homo, 2.8 million years ago, and during the time when Australopithecus afarensis cheap moncler jackets wholesale (the famous “Lucy”) lived in East Africa.

On May 21, details of 3.3 million year moncler coats for kids old stone tools from Kenya the oldest yet discovered were published by Sonia Harmand and discount moncler jackets her colleagues in the journal Nature. The tools consist of sharp flakes, large cores moncler coats outlet and flat anvils. According to an NPR report, “While they weren’t as sophisticated as tools that have been associated with the first humans, they were definitely crafted intentionally.”

moncler mens jackets That intentionally fashioned tools predate our genus doesn’t surprise me; it makes abundant evolutionary moncler coats cheap sense, Moncler Factory Outlet given what we know of moncler jackets mens sophisticated tool use and tool making among animals moncler jackets toronto as diverse as chimpanzees and birds. (The word “deyiremeda” means “close relative” in the local Afar language.)

Whether moncler jackets for women you find this news surprising depends, in part, on whether you’re a cheap moncler lumper or splitter. The Wikipedia definition of these terms works well for our purposes:

“A ‘lumper’ is an individual who takes a gestalt view of a definition, and assigns examples broadly, assuming that differences are not as important as signature similarities. A ‘splitter’ is an individual who takes precise definitions, and creates new categories to classify samples that differ in key ways.”

moncler sale outlet Haile Selaisse et al.’s decision to create a new category for this East African hominin comes from the splitter camp and is bold (though certainly not unprecedented) given that the fossil material they uncovered consists entirely of jaws and teeth. These scientists are confident that there’s adequate morphological variation in the maxilla (upper jaw), mandible (lower jaw) and teeth compared to bady moncler womens earlier described hominins to justify the moncler outlet online store new species designation. According to the Cleveland Museum of Natural History website:

moncler outlet moncler outlet usa store “Australopithecus deyiremeda differs from Lucy’s species in terms of the shape and size of its thick enameled teeth and the robust architecture of its lower jaws. When I asked Tattersall about the new fossil material, he responded by email on Monday in this way:

“I have only seen small publicity photos, but the new species seems entirely reasonable. In fact, my book is all about the long struggle to get paleoanthropologists moncler outlet canada to recognize diversity in human evolution, and this moncler outlet mall adds grist to moncler outlets usa the mill.

cheap moncler coats The moncler jackets outlet morphological distinctiveness of the new fossils sets them apart from anything else known in this time range or as far as I can tell moncler jackets on sale any other. This diversity brings human evolution even more into line with that of other taxa, and yet farther away moncler jackets cheap from the dogma of hominid linearity that has reigned since 1950.”

cheap moncler jackets It’s certainly true that linearity, as a descriptive term for what happened during human evolution, is now a discarded concept: At least two other hominins (Kenyanthropus platyops and Australopithecus bahrelghazali) are moncler outlet thought to have lived in Africa during this same time period.

Still, it’s far from easy for paleoanthropologists to know cheap moncler coats for women when it’s better to carve up continuous variation in morphological traits by naming a new species and when to embrace, instead, the idea of variation within a species.

moncler outlet sale University of South Carolina anthropologist Andrew White considers some of the challenges surrounding the species concept in a blog post moncler outlet uk published May 29. White discount moncler outlet first moncler jackets clarifies that, among various ways to define what a species might be, in the paleoanthropological context the biological species concept is moncler jackets outlet online most relevant.

moncler outlet “A biological species is reproductively isolated from all other biological species. The biological species concept is perhaps the one most frequently applied in biology, especially moncler outlet location to living populations of plants and animals.

I think a cheap moncler jackets outlet ‘biological species’ is also moncler coats what most people, paleoanthropologists included, mean when they talk about “species” of hominids.

monlcer down jackets moncler outlet ny Because reproductive isolation is the entire basis of the biological species concept, individuals in a biological species (by definition) could not and did not interbreed with any of their contemporaries outside their own species.”

cheap moncler outlet An assertion that Au. deyiremeda is a new species equates, then, to an assertion that it could not have interbred with other hominins living nearby at the time. For White, this causes concern:

cheap moncler sale “First, I think it’s impossible to operationalize consistently and objectively (how can you determine if the populations represented by fossil individuals were capable of inter breeding?). So, I don’t trust that ‘species’ that are moncler jacket outlet equivalent in taxonomic terms reflect populations that moncler outlets uk are equivalent in evolutionary terms.

Second, I think naming lots of cheap moncler jackets ‘species’ short moncler outlet kids circuits our study of what variability in the fossil record means by erring on the side of attributing it to species level differences. Under the biological species concept, species are non overlapping, nominal categories, moncler chicago and speciation is a one way street. By moncler outlet store calling a fossil hominid a new biological species, you are making a statement about the moncler outlet woodbury nature of the relationship between that fossil and all other fossil hominids. Given the sparse nature of the fossil record, I don’t think that we can really make those kinds of statements with much confidence.”

buy moncler jackets moncler coats sale White’s two points resonate with moncler outlet online me, especially the idea that naming a new species means that scientists automatically make probably premature statements about womens moncler jackets relationships among hominins.

moncler outlet online Further, naming a new species brings more global, splashy media attention (and possibly more grant dollars, though I know of no way to test that particular hypothesis) compared to the weaker response won by a description of newly understood intraspecific variation. This last point may seem cynical, and I don’t mean to suggest it’s a primary motivator in the case of Haile Selassie et al. Yet, I do think it’s a reality of the ways in which science discoveries are rewarded (or not).

cheap moncler Haile Selassie et al.’s naming of the new australopithecine species leads them to emphasize in their Nature article the “incontrovertible evidence” showing multiple hominin species existed in East Africa during a crucial time period in our past. Taxonomic debates aside, the evidence is indeed rock solid that before we became human, our hominin ancestors were behaviorally and cognitively complex primates. Their evolutionary story moncler jackets kids is our story, too.

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