Subject: [Tweeters] biodiversity question
Date: Mar 8 14:05:10 2011
From: Dennis Paulson - dennispaulson at comcast.net


Kelly,

I think one reason for their great diversity is that insects can do so many more things than millipedes and terrestrial mollusks, among other terrestrial invertebrates.

They have evolved into just about every food niche you can imagine, which huge numbers of both predators and herbivores, while millipedes and mollusks (and, for example, spiders) are much more limited in what they eat and how they obtain it.

Insects evolved flight, the only invertebrates to do so. This allowed them to colonize new lands fairly easily and then speciate when they got there. It allows them to access all levels of all terrestrial habitats.

They have evolved an anatomy and physiology that has allowed them to radiate into desert environments much more successfully than most other invertebrate groups.

They have been very poor at colonizing the oceans, which were already full of critters, but there are even a few insect types (marine water striders) out in the middle of the oceans and quite a few living in the salt marshes at the edges.

Just a few ideas.

Sorry, I know we have deviated from birds somewhat, but after all, birds do eat insects.

Dennis
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Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net


On Mar 8, 2011, at 12:05 PM, tweeters-request at mailman2.u.washington.edu wrote:

> Date: Mon, 7 Mar 2011 19:30:24 -0800
> From: "Kelly McAllister" <mcallisters4 at comcast.net>
> Subject: RE: [Tweeters] biodiversity question
> To: "'tweeters'" <Tweeters at u.washington.edu>
> Message-ID: <000801cbdd41$2bf9b930$83ed2b90$ at comcast.net>
> Content-Type: text/plain; charset="UTF-8"
>
> So why, among the many kinds of invertebrates, are insects being singled out as so extraordinarily numerous? Has that really been established? Based on what little I've observed, watching Bill Leonard as he collects new families, genera, and species of millipedes and terrestrial molluscs, we really don't have a good idea how many "species" (hahr) there are among the many invertebrate groups.
>
> Kelly McAllister




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