Is the Biological Species Concept a "minority view"?

| john hawks weblog

http://johnhawks.net/weblog/topics/evolution/species/species-problem-g...

john hawks weblog

paleoanthropology, genetics and evolution Home

Welcome!
Whether it's your first time here, or you've been

Is the Biological Species Concept a "minority view"?

M on , 2 0 11 -02 -07 1 7:25 -Jo hn H a wk s

reading for years, you may be interested in:

Who is John Hawks? What's this site about? Site FAQ

Last week, Science ran a couple of items by Ann Gibbons that give further perspective on the discoveries last year that Neandertals and Denisovans both contributed to the ancestry of recent human populations. The sidebar piece, titled, "The species problem," raises the taxonomic question:
Our ancestors had sex with at least two kinds of archaic humans at two different times and placesand those liaisons produced surviving children, according to the latest ancient DNA research (see main text, p. 392). But were the participants in these prehistoric encounters members of separate species? Doesn't a species, by definition, breed only with others of that species?

Malapa Soft Tissue Project

Be a part of a unique open science experiment.

I get the most awesome quote in the short article, because I get to defend the Biological Species Concept! Gibbons describes this as a "minority view among paleoanthropologists." I can't disagree: Get a dozen paleoanthropologists in a room, and I bet only 1 or 2 will seriously propose that we could apply BSC to hominins. This would be sort of understandable, if we were limited to the evidence of 15 years ago, with no genetics. It just wasn't really possible to test the hypothesis of interbreeding among populations, not at the scale at which we can today. There was always skeletal evidence that suggested Neandertals had contributed to later populations, as many of us pointed out repeatedly. But it was hard to quantify the phenomenon, and without quantification, it was possible for people to argue that interbreeding had been "evolutionarily insignificant". Paleoanthropologists have instead held species concepts that did not use interbreeding as a primary criterion. Many adopted Cracraft's Phylogenetic Species Concept, or Wiley's treatment of

Favorite links

My sketchbook
Here are some of my rougher drafts.

Hobbits
Homo floresiensis was

1 of 6

2/15/2012 12:20 PM

Is the Biological Species Concept a "minority view"? | john hawks weblog

http://johnhawks.net/weblog/topics/evolution/species/species-problem-g...

Simpson's Evolutionary Species Concept. Both of these define species in terms of morphological characters visible to the systematist, although they differ with respect to the pattern that justifies recognizing a species. Much of this is just ridiculous now. Genetic evidence shows a substantial amount of interbreeding between these Pleistocene groups. Lots of living humans trace more than a couple of percent of their genomes from some ancient non-African population; some may derive more than 8 percent of their ancestry from such populations. That's not rare hybridization. With this kind of evidence, we can apply the BSC. One hangup: maybe we can't prove that our Neandertal ancestors contributed genes in proportion to their population numbers. Maybe a large fraction of their genes had a fitness disadvantage in the later population. But this is a hypothesis, not a fact. Any estimate of the fitness of Neandertals in mating with their non-Neandertal contemporaries has to take account of the demographic growth of later populations, including selection on new gene variants. We know for a fact that some Neandertal genes are today very common -- for example, one 100-kilobase region occurs at a frequency of 28 percent outside of Africa. Any assignment to a species is a hypothesis, provisional on finding new facts to refute it. For the moment the facts point to them being the same species as us. What do we do with a population like the Neandertals, or the Denisovans? Each was more genetically distant from the average living human than members of living populations are from each other. Each evolved during a long period of isolation or strongly restricted gene flow from each other and from sub-Saharan Africans. Still, the level of genetic difference among these populations was comparable or less than that separating populations of great apes that historically have been recognized as subspecies. So that's what I would call them. Subspecies of Homo sapiens. As a postscript, I think that whoever came up with the idea of "Denisovans" as a population name has done us a tremendous favor. The great benefit of the name, "Neandertals", is that we could talk about them without trotting out a taxonomic name. Now we have something similar in eastern Eurasia. Also Jerry Coyne, coauthor of Speciation, discusses the issue. Tags: Neandertal DNA Denisova

the topic of the day when I launched the blog (photo credit: Ryan Somma, CC)

Paleodiet and evolution

The diet of our ancestors has become a huge topic. I cover the science.

Recent stories Low-velocity spatter from the Neandertal palette

A discovery of red ochre use by ancient Europeans before 250,000 years ago

Orangutan loris capture and meat-eating

A discussion of early hominin meat-eating emerges from observations of orangutan hunting

The thrifty brainotype

Were brains constrained by information efficiency, or energy efficiency?

Aleut origins and relationships

A news article covers research into the history of Aleut populations.

Public interests in data from federally funded research

My response to a federal Request for Information on the topic of digital data

2 of 6

2/15/2012 12:20 PM

Is the Biological Species Concept a "minority view"? | john hawks weblog

http://johnhawks.net/weblog/topics/evolution/species/species-problem-g...

Neandertals taxonomy species concepts species Synopsis: After Neandertal genes are found in us, I find myself defending the obvious idea that they're Homo sapiens.

access to federally funded research

Stature estimates for Sima de los Huesos

The long bones of the Atapuerca people double our information about early human statures

Looking over a

Related posts Mailbag: Neandertal interbreeding

Mailbag: Neandertal genes across the Strait of Gibraltar Which population in the 1000 Genomes Project samples has the most Neandertal similarity?
Europe has a touch more Neandertal than East Asia; Tuscans have more than any other European sample

Neandertal's shoulder
A study of the glenoid fossa finds a pattern across the genus Homo, and similarities between a Vindija specimen and more recent humans

Denisova APOE status A quick look at your Neandertal fraction Over coffee Mailbag: Did Neandertals have the derived MCPH1 allele? Mailbag: Neandertal derived SNP alleles Neandertal introgression, 1000 Genomes style
We're quantifying the amount of Neandertal ancestry in whole genome data from living people.

Best practices and tips for Twitter in the higher-ed classroom

Thinking about integrating Twitter in your class communication strategy? Here are some pointers.

James F. Crow, 1916-2012

In memory of a friend and colleague, one of the most prominent figures in the history of genetics

Mailbag: Neandertal-human comparisons When anthropological and geological facts collide

Weidenreich's introduction to the Sinanthropus cranial monograph illuminates some issues I'm facing with ancient genomes.

How widespread is Denisovan ancestry today?

A new paper contradicts earlier work, by suggesting a widespead Denisovan legacy in south China

Schools of fish, schools of thought

A paper on decision making in groups of animals prompts me to think about science.

Archaic genome snooping from GWAS Hawks lecture at University of Birmingham Sept. 22 No Neandertal safe sex
A new paper claims humans and Neandertals were reproductively incompatible. I don't think so.

Is humanistic research a waste of time?

A scholar tries to quantify the value of humanistic research.

Neandertal introgression, 1000 Genomes style

We're quantifying the amount of Neandertal

3 of 6

2/15/2012 12:20 PM

Is the Biological Species Concept a "minority view"? | john hawks weblog

http://johnhawks.net/weblog/topics/evolution/species/species-problem-g...

ancestry in whole genome data from living people.

"Transformative" research can't come from milquetoast

Grant agencies should set transformative objectives, not set aside money for transformative research

Pigmentation of archaic humans: introduction

I describe the outline of our project on the pigmentation genetics of the Neandertal and Denisova genomes

When anthropological and geological facts collide

Weidenreich's introduction to the Sinanthropus cranial monograph illuminates some issues I'm facing with ancient genomes.

Follow @johnhawks on Twitter! Check me on Google+

Support
I'm staying independent and advertising-free. Independence means I can have things like the 12,000-reference live online bibliography. No advertising means I can reach more teachers, students and international readers. But it takes some money to run the place. I've been supported over the years by small donations from a few generous readers.

4 of 6

2/15/2012 12:20 PM

Is the Biological Species Concept a "minority view"? | john hawks weblog

http://johnhawks.net/weblog/topics/evolution/species/species-problem-g...

Thank you for your support!

If you access Amazon through one of my links, Amazon will give 6% of every purchase (and more for certain items or rentals) to the site. It doesn't cost you any more, but it really helps out here. Some of my most generous supporters are companies and departments who use these links with their purchasing cards. The price is the same, the difference is that a small percentage supports this site. Either this link, the search box below, or any other Amazon links on the site will work. American version:
Search Amazon:

The Canadian version:

Search Amazon:

And the UK version:

Search Amazon:

Powered by Drupal

Neandertals

Denisova

Acceleration

Malapa

5 of 6

2/15/2012 12:20 PM

Is the Biological Species Concept a "minority view"? | john hawks weblog

http://johnhawks.net/weblog/topics/evolution/species/species-problem-g...

For years, I've worked on their bones. Now I'm working on their genes. Read more about the science studying these ancient people.

From a finger bone of an ancient human came the record of a completely unexpected population. My lab is working on the science of the Denisova genome.

The advent of agriculture caused natural selection to speed up greatly in humans. We're uncovering some of the ways that populations have rapidly changed during the last 10,000 years.

Just outside Johannesburg, the Malapa site is producing some of the most exciting finds in human evolution. This site is the headquarters of the Malapa Soft Tissue Project.

About the author

JOHN HAWKS is Associate Professor of Anthropology at the University of WisconsinMadison. I was trained as a paleoanthropologist, studying human evolution from an integrative perspective. My research focuses on the processes affecting human genetic evolution across the last 6 million years. Text and images copyright 2011 John Hawks unless noted otherwise.

6 of 6

2/15/2012 12:20 PM