ADAPTIVE RADIATION- how the heck does this relate to White Sands lizards.

This image of White Sands, NM is from google maps.

Simone- signing on.

So Schluter focused a lot on the definitions of Adaptive Radiation and other concepts surrounding the term. Let's see what he says.
On the first few pages of chapter 3, Schluter outlines the four main features of an adaptive radiation. Here they are in abbreviated form:
1. common ancestry of component species
2. phenotype-environment correlation
3. trait utility (certain traits have a fitness advantage in respective environments)
4. rapid speciation.

We're not by any means suggesting that adaptive radiation has or will occur in White Sands lizards. But the parallel colonization by the three lineages is interesting in this context because many believe (Lister, Wilson, Simpson etc.) that this invasion of open and new territory is a key component of the initial stages of an AR. We'll talk about this concept of Ecological Release in more detail later.

Why don't we think that AR wouldn't occur in White Sands lizards?
We discussed this a little when Kayla and I met last time. Well first of all, when we look at adaptive radiations on islands... well, see, that's the thing. Adaptive radiations are on islandS! Not just one! Hawaiian silverswords, fruitflies and honey creepers, Galapagos finches and Caribbean anoles- they all inhabit archipelagos. Even if we consider White Sands as a relatively isolated and recently formed island... it is just one. Even the subdivision of interdune areas by high uninhabitable dunes is only ever temporary. The dunes are always moving, changing the configuration of habitable, vegetated space. One might imagine that the populations of lizards in White Sands are quite dynamic. And an adaptive radiation in the face of that kind of gene flow? I think not!

But some adaptive radiations seem to be born from multiple colonizations of the same lineage in one 'island' (stickleback, cichlids, anoles...):

Could we get an adaptive radiation of lizards in White Sands due to several invasions from surrounding dark soils habitats?
What do population genetics tell us about the structure of populations in White Sands?
Would this be more common in certain lizard species? (i.e. Holbrookia populations outside White Sands are far more disjunct and they have no continuous distribution over the ecotone from dark soils to White Sands).
Is there enough distinctive niche space for lizards in White Sands? Or is niche space indeterminate, with diversity begetting diversity (Whittaker)?

Over to you, Kayla!