Beavers could be reintroduced to Wales...

[no-one in particular]

In your head Mark may be, but alas in science they are distinctly different, as no doubt Darwin would concede 158 years on from publication of The Origins of Species

And Darwin would have conceded they are all intrinsically linked, that's what he said in the Origin of Species. Proved it in fact.

 

[ken more]

I watched a programme the other day that said about 1400 people die every day or even hour, Not sure which now, because they can't get clean drinking water or rather the diseases that brings. Just though i would throw this in to the mix.

 

[no-one in particular]

Anyone noticed the difference in fish, I have, Kennet barbel look different to Avon barbel, seen quite a few differences in chub. Roach from one stream I fish look decidedly different from roach in another river just 11 miles away. One are very silvery with red fins, the other have very dark backs with very pale orange fins or almost no color at all.. And who knows what differences might be going on under the skin surface; there must be genetic differences in these populations of roach; aka Darwinism..
There were two or three big barbel introductions in one river near me, they all disappeared without trace, the river looks suitable in parts and no one understands why, could it just be although they were barbel they were a "different" barbel who did not have the right genetic make up for the river.

 

[The bad one]

All fish have the ability to change colour at will to fit in with the water they are in. It's a survival strategy. Ie. Adaption. As to barble buggerin' off not unusual at all, read S. Clough's papers on fish movement.

 

[chub_on_the_block]

Roach in the Wensum have a distinctive thick set appearance, and in clear water habitats have more silvery blue scales, and redder fins compared to roach from a turbid water that are often drab and colourless and rather anaemic looking. Theres also the well known variation in Crucian body shape possibly linked to productivity of a water and predation risk. In each case if you transferred specimens from one waterbody to another there would be no guarantee that future generations would retain the same characteristics.

I reckon if you stocked a turbid lake with Wensum roach the next generation would be as equally drab as those that that had lived there for generations. Partly this may be explained by higher mucous covering in a more stressful environment (the turbid and usually less well oxygenated one) where risk of infection is also greater.

I doubt any of the differences are genetic, just responses in growth and development to different environmental conditions.

 

[thecrow]

Its not always the case that creatures of the same species can do well in environments they are not used to, trout water pike are an example that imo if removed from the high protein environment they live in to say a gravel pit would loose weight, are barbel in a still water another example?