Orangespotted sunfish prey/body type correlation
Posted 07 May 2015 - 09:45 PM
Lower Ogeechee/Ogeechee Coastal Drainage
Posted 08 May 2015 - 08:43 AM
This isn't with sunfishes, but I learned about this a while back about Lake Trout (Char). The body morphology of these two distinct phenotypes is pretty amazing. Pectoral fin size, mouth size and shape, etc. varied depending on where in the water column the fish live and forage (type and location). One of the folks working on a similar project showed a group of us photos of all the trout they caught. The differences between some of them were mind blowing.
Posted 08 May 2015 - 11:32 AM
Lamarck's theory (now generally un-accepted) was that animals could pass on traits that they acquired during their lives, e.g. giraffes stretching their necks to reach the highest leaves. What Steve and Willie are describing is "phenotypic plasticity" -- the ability to grow and develop differently in response to local environmental conditions. Plants of course are the real masters of this. It doesn't have to do with passing on acquired traits to the next generation like Lamarck's theory. But in certain instances, Lamarck was sort of right -- some organisms really can incorporate and pass on genes acquired from others (but not by stretching their necks).
It sounds like Lamarks theory with giraffe necks, which isn't really excepted anymore. Nutrition might have some factor in color, muscle, bone and fat composition. Maybe it has something to do with that.
Hangin' on the Neuse
"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel
Posted 09 May 2015 - 09:50 PM
From a related but slightly different angle, the article entitled: "Morphological change and phenotypic plasticity in native and non-native pumpkinseed sunfish in response to competition" by Yavno, Rook, and Fox (2014) proposes that competition affects body shape in Pumpkinseeds. This difference would presumably also affect prey selection and/or availability.
Posted 12 June 2015 - 09:29 AM
It might be phenotypic plasticity, but there isn't really enough information to determine that. I am sure nutrition might have a slight effect on color and deposition, but nothing major. I might be wrong but I doubt fish will be noticeable different if you feed black worms vs bloodworms or NLS pellets vs Hakari pellets.
I skimmed through the trout article and think a lot of the traits are more genetic base then environmental. Part of the article mentioned the position of the mouth on trout. Trout found on the top have their mouth located on top because of genetics and the effects of natural selection. I doubt the position of the mouth will shift due to a change due to water depth. It is the position of the mouth that determines where they will be found in the water column and not the other way around. Some of the traits like color might be due to environmental changes.
In Lamarks writings he stated that organisms can change their body type to a certain extent. When he wrote about the giraffes he stated that a giraffe can extend his neck throughout his life time but is limited to how much he can extended. As generations go went the addition length kept getting passed down.
Posted 13 June 2015 - 10:54 AM
For those interested in Lamarkian ideas, check out Epigenetics. It's quite an interesting read.
This business is real.
Conditions I am familiar with that promote phenotypic plasticity involve physical activity such as handling large-tough versus small-delicate food items. The epigenetics business, though real, seems to be overly played or at least not understood by much of genera public discussing it.
Posted 21 June 2015 - 01:42 PM
Perhaps it's due to a sort of survival-of-the-fittest thing. For example, if the majority of available prey items are fast and must be pursued, the naturally slender/fast sunfish babies would do better than the thick/strong ones, so you end up with lots of slender ones that outcompeted all the thick ones. Or vice versa, you get big thick sunnies if the available prey had to be thrashed around and killed. In an environment with lots of easily grabbed prey, you'd end up with a mix.
Posted 06 July 2015 - 10:37 AM
There was a paper out of the Wainwright lab look at feeding morphology (not body morphology, sorry) in pumpkinseed sunfish. They found that it was mainly a result of phenotypic plasticity.
Here's the reference:
Mittelbach, Gary G., Craig W. Osenberg, and Peter C. Wainwright. "Variation in feeding morphology between pumpkinseed populations: phenotypic plasticity or evolution?." Evolutionary Ecology Research 1.1 (1999): 111-128.
I can send the actual paper if anyone wants it- just PM me.
Posted 07 July 2015 - 07:24 AM
Posted 07 July 2015 - 11:40 AM
I don't think this is very relative, but a bit maybe.
Apparently there are two populations of rainbow smelt in the great lakes, One spawns in streams, the other spawns on sandbars and shoals farther out in the lake. Both are the same species. It seems that in lake Erie that people are catching fewer and fewer smelt. They have targeted them during the spawning run for who knows how long. These anadromous populations seem to be dwindling, but the shoal spawners are doing fine. So there are still plenty of smelt. I assume this was nature's way of preserving the species through droughts or floods. It has been a while since I read about this, so I am sure I am missing some points, but I found it very interesting.
Along with the arctic char, I think there are several lakes in Eurasia? that have brown trout populations that though the same species, there are three different phenotypes that occupy three different niches.
The member formerly known as Skipjack
Posted 08 July 2015 - 07:35 AM
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