Evolutionary Biology Online Journal Club

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#EBJClub 2.6 – Is regional species diversity bounded or unbounded?

Today’s meeting will be through Google+ hangouts, so here are a couple useful resources:


Last meeting for Season 2 – and a EBJClub/PEGE crossover!

Hey everyone!

Sorry for the very delayed post, this has been a hectic end of semester to me. I was supposed to choose the next paper for discussion on something related to sexual selection and speciation, but I think we’ve figured out something cooler to do!

Lynsey McInnes (@McLynsey) and Will Pearse (@willpearse) have been running the very, very cool PEGE (Phylo-Eco-Geo-Evo) Journal Club since early this year. It follows a format that is a little different than our EBJClub: they choose a paper to thoroughly review and comment on in their webpage, creating a really nice archive of their impressions of these papers, while at the same time conveying their importance and main points in a very accessible way to those interested. They also have guests come from time to time and choose a paper, contributing to the dialogue. It’s really great and I’ve learned a lot from reading their posts – you should definitely check it out!

So you can see that the goal of PEGE and EBJClub are similar – promote the reading and discussion of important topics in evolutionary biology among students and researchers that don’t necessarily share (anymore) the same lab -, but we have ended up with quite different ways of doing so, which is interesting of itself. I had known of their journal club for a while and had been following their posts, but a couple of weeks ago it kinda clicked on me – “hey, we should do something together!”

So I contacted them and here we are! Lynsey and Will were kind enough to accept my invitation, choose our next reading and will be joining us for the next discussion! At the same time, PEGE will have a post on the same paper, which should help anticipate some of the issues and questions we might have, as well as highlight interesting topics that are worth discussing in the Google Hangout.

The paper chosen is a recent Biology Reviews article by Howard V. Cornell titled “Is regional species diversity bounded or unbounded?”. Don’t let the title fool you – it might seem kinda specific, but a quick read of the abstract will show that this paper brings together many (perhaps all?) the main topics we have discussed throughout the semester, and really is a perfect way to wrap up the discussion on speciation and biological diversity!

As is usual for Biology Reviews papers, this paper is long, conceptual and thus might require a good, careful read to take the most out of it. Therefore, I am suggesting we meet Monday, May 15 13 at our usual 4:30 EST time slot to discuss it – leaving a good 10 days to go over the paper.

Does that sound good? I’m excited, and I can’t wait to see how it goes!

Howard V. Cornell (2013) Is regional species diversity bounded or unbounded? Biological Reviews 88:140-165.

Abstract. Two conflicting hypotheses have been proposed to explain large-scale species diversity patterns and dynamics. The unbounded hypothesis proposes that regional diversity depends only on time and diversification rate and increases without limit. The bounded hypothesis proposes that ecological constraints place upper limits on regional diversity and that diversity is usually close to its limit. Recent evidence from the fossil record, phylogenetic analysis, biogeography, and phenotypic disparity during lineage diversification suggests that diversity is constrained by ecological processes but that it is rarely asymptotic. Niche space is often unfilled or can be more finely subdivided and still permit coexistence, and new niche space is often created before ecological limits are reached. Damped increases in diversity over time are the prevalent pattern, suggesting the need for a new ‘damped increase hypothesis’. The damped increase hypothesis predicts that diversity generally increases through time but that its rate of increase is often slowed by ecological constraints. However, slowing due to niche limitation must be distinguished from other possible mechanisms creating similar patterns. These include sampling artifacts, the inability to detect extinctions or declines in clade diversity with some methods, the distorting effects of correlated speciation-extinction dynamics, the likelihood that opportunities for allopatric speciation will vary in space and time, and the role of undetected natural enemies in reducing host ranges and thus slowing speciation rates. The taxonomic scope of regional diversity studies must be broadened to include all ecologically similar species so that ecological constraints may be accurately inferred. The damped increase hypothesis suggests that information on evolutionary processes such as time-for-speciation and intrinsic diversification rates as well as ecological factors will be required to explain why regional diversity varies among times, places and taxa.

adaptive radiation carrying capacity coexistence diversification niche
niche conservatism phylogenetics saturation species-area species diversity species-energy