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Re: Evolution in a microcosm
Jody, while I am not personally flaming you, I think
that you have missed the subtleties of Evolutionary
theory. The behavior is indeed more than a hungry
fish. Hatching an amphibian is not really in any way
related to evolution. The process of change in a
species is one that takes a very long time and
behavior that attempts to influence the continuation
of a set of genes over another is indeed evolutionary
process. Survival of the fittest is a simple way of
looking at a complex situation. Every organism
competes to insure that its own genes are continued,
even humans. Any mechanism used to give a set of genes
an advantage (killing or eating your "opponent's"
offspring is surely effective). For example, more
colorful and vibrant males may be the ones to
reproduce instead of less colorful ones. This keeps a
speciesvibrantly colorful. If a situation developes
where those (colorful)males become more heavily
predated (is that a word?) then there will be a
decrease in the colorful genes (very simplistic
example) leading to the species becoming less colorful
over time. This is evolution of that species. Another
example (to use the amphibians you mentioned) of this
is a certain ambytomid slamander. It did not exist
until two ranges of separate species overlapped for
some reason. In the zone where they overlapped, cross
breeding resulted in a hybrid that was fertile. That
hybrid was successful to the point that it became
established in the zone leading to a third and new
species of salamnder. This is a real thing that
happened which we studied in my 500 level herpetology
seminar. I do not recall the three species involved
other than they were ambystoma species. In this
example they did not need to eat the opposing young.
THey mearly out-reproduced the other two species in
that area.
--- Jody <fishbox@bellsouth.net> wrote:
> Tony,
> Good luck with your rams, but I don't think that was
> really evolution at work - just a hungry fish. And
> it could have been any fish. Now if the rams were
> able to hatch an amphibian, that would be different.
> Personally, I don't think that will ever or has
> ever happened. Anyway, I hope you get a successful
> spawn!
> -Jody
>
> >
> > From: "Anthony Baker"
> <anthony_w_baker@hotmail.com>
> > Date: 2002/03/12 Tue AM 10:05:14 EST
> > To: apisto@listbox.com
> > CC: bakera506@earthlink.net
> > Subject: Evolution in a microcosm
> >
> > So, last night I witnessed Evolution at work in my
> 29G plant tank. The tank
> > contains a trio of Blue Rams, a couple black
> neons, 3 molly fry, 3 ottos, 2
> > SAEs and ~12 ghost shrimp, bunch of red ramshorn
> snails and MTS. Because
> > this is a aquascaped tank, I didn't have any
> "normal" spawning locations,
> > just a few artistically placed rocks and
> driftwood.
> >
> > The tank stats are:
> > KH / GH: 3-4/6
> > CO2: 25-35ppm
> > pH: 6.65-6.70
> > NO3 - ~5-10 (added weekly for plants)
> > PO4 - ~0.5
> > Weekly water changes.
> > Temp ~81F
> >
> > Anyhow, after I fed the fish their allotment of
> live blackworms, I moved on
> > to feed my other tanks. I returned 15 minutes
> later, and sure enough, the
> > male and the "alpha" female were dancing around a
> little depression in the
> > substrate (flourite) hidden behind some tall
> plants. I peered in and could
> > see ~75-100 eggs (not bad for a tiny female) right
> on the flourite. The
> > male was busy fanning the eggs. The interesting
> part: the "beta" female,
> > who lately has been chased by both the a-female
> and the male, kept coming up
> > to the pit and appeared to "entice" the male away
> from the eggs. Then, she
> > would circle around the whole tank while being
> pursued by either the male or
> > both the male and a-female. A few times, the
> b-female would circle back to
> > the pit and quickly gobble down a few eggs! The
> male would chase her away
> > again, and the whole thing would start again! The
> male also began chasing
> > the a-female around, allowing the beta-female even
> more snack time!
> >
> > Evolution at work! The b-female was clearly
> eating the eggs to increase her
> > fitness level and simultaneously reducing the
> chance of the a-female
> > spreading her genes! Very interesting! Another
> consideration is that it is
> > quite likely that the trio are genetically related
> -- probably even siblings
> > -- as I got them from the LFS. In many higher
> animals, genetically related
> > conspecifics often take _some_ responsibility for
> care of young -- eg.
> > "aunt" chimps often take turns caring for baby
> chimps or watching juveniles
> > while the mother gets some relaxation. Apparently
> not so with Rams!
> >
> > I also think I was pretty lucky to get two true
> females and one male -- I
> > was a bit worried after reading about the lack of
> females being imported
> > from the Far East. Perhaps the trio was even from
> a local breeder.
> >
> > Well, an hour later, I checked back on the tank
> and noticed that the male
> > and alpha-female were doing a "spawning dance" on
> the other side of the tank
> > near the driftwood. The female's ovipositor was
> still very extended and
> > both had full coloration. The beta-female was no
> where in sight, and it
> > looked like most of the eggs were gone. So, I am
> hoping they do better on
> > the next round!
> >
> > I am not prepared space-wise to dedicate a tank to
> breed these fish, but
> > wouldn't mind having a successful spawn in their
> present tank. If anyone
> > has suggestions that might help, I would
> appreciate it. I could pull out
> > the other female, but think that she might be next
> in line to lay eggs! I
> > added a small clay tray (for flower pots) with
> some fine sand in it, so
> > maybe the Rams will like that more?
> >
> > TIA,
> > Tony
> > BTW - My new pair of A. trifasciata is settling in
> nicely and my new male
> > double-red aggie is adjusting to his new home...
> Still seems a bit ragged,
> > but hopefully some good food will fix him up soon!
> >
> >
> >
> >
>
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> >
> >
> >
>
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>
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