🚀 go-pugleaf

digenetic trematodes, such as Fasciola hepatica (the liver fluke) pass
through several hosts, and undergo both asexual and sexual reproductive
phases.  The utilise a snail as an intermediate host where the asexual
reproduction occurs, and then migrate into the eye stalks of the snail.  The
snail basically carries the developing parasites to teh tops of plants,
where they can be eaten by sheep and cattle (the definitive hosts) and the
cycle starts over.  This multiple host and polymorphism is a feature of this
branch of the Platyhelminthes.

hope this helps

Rick

Che Guava wrote:

> I have for some time thought that social Darwinism was based
> on a crude simplification derived from an even cruder simplification:
>
> 'survival of the fittest'
>
> It seems, as we develop a more sophisticated understanding of
> complex ecologies, that co-operation may in fact be the far more
> important
> organising principle.
>
> I was reminded of this watching Attenborough when he made a passing
> comment
> that we are only 20% us.
>
> By which he meant that the micro-organisms, bugs and bacteria with
> whom we live in symbiosis (or are hosts to their parasitism, a form of
> unconscious biological charity  ;-)  are the majority partner.  8^o
>
> Now some of these critters we can't live without..   gut bacteria
> for example, are essential to digestion... but I thought this was a good
>
> forum to seek some clarification on two related issues:
>
> Mitochondria..  I remember a sci-fi story that suggested these were
> alien DNA sitting in the drivers seat of our cells piloting us all
> toward
> a civilization which would ultimately develop technology advanced
> enough to return them home.   ;-)
>
> If ever there was an opposite to anthropomorphism, that must be it.  B^)
>
> My question is..  are these mitochondria truly 'alien' i.e., not of our
> DNA,
> but like the other 80% Attenborough alluded to,  'the other'
>
> And what basically, is their function?
>
> The other query is really a long shot.. I'm just hoping to encounter
> someone with equally eclectic interests on this one..
>
> At at friends farm while housesitting I sampled much of their bookshelf
> of an evening, by the old pot bellied stove.
>
> One story, (author and title noted but subsequently lost), described a
> micro organism
> which I found absolutely astonishing. (It was, I understood, a work of
> non-fiction
> of the genre.. 'strange but true').
>
> It described a bovine parasite.  during it's lifecycle it is excreted
> into the soil,
> from there it passes into ants.
> Now at some point in its lifecycle it migrates to the ants central
> nervous
> system, and causes it to climb to the very top of grass stalks!  8^o
>
> >From there it has the best chance of being munched by grazing cows!!!
>
> Now I understand the principles of natural selection.
> I subscribe to the theory of evoluution..
>
> but bugger me dead..  modifies ant nervous system in such a way as to
> override ant control,  causing behavioral change which amounts to
> turning it
> into a vehicle for takeoff???
>
> Q1  anyone else aware of this life cycle
>
> Q2 Anyone know the name /  author of the book?
>
> Q3 Anyone got similar stories.  (non-fiction preferred ;-)
>
> Thanks
>
> Che
> -----
> The woods are lovely, dark and deep,
> But I have promises to keep,
> And miles to go before I sleep,
> And miles to go before I sleep.
>
>  -Robert Frost "Stopping by Woods on a Snowy Evening"