Evolution and Coral

[thecichlidpleco]

I am giving a presentation in an evolution class on "the voyage of the beagle" which is the trip darwin took and wrote about in which he based his orgins of species on. The chapter I chose to write about was about coral formations. So I wanted know if anyone had information on how coral may be used to prove or lead to Darwins belief in evolution.

 

[cutegecko3]

Stoney corals go all the way back to the cambrian(500 million years ago)with no link to them or from them.You may want to pick another topic.I hear the reptile to mammal transitions are pretty convincing.

 

[demonsp]

Im very uneducated and very confused on the whole "which came first thing" but think that any organizium (sorry as factors kept me from a simple grade school education ) that can survive in any one situation will in time only spread and learn to adapt to any surrounding inviroment if givin the ample time to do so. Life anywhere in this wierd and infinate universes would only want to do the same.

The one that gets me is all other species seem to create a harmony with its surrondings and thrive as we as humans only spread and destroy. We are human kinds worst enemy. (Matrix)

 

[greenbean36191]

Darwin wasn't writing about the evolution of coral species when he was on the Beagle. He was writing about the evolution of coral atolls as geologic structures.

Corals are an interesting model for looking at evolutionary processes though. We can often see the transitions between species. One of the most famous examples of this is the Montastrea annularis complex. If you looked at one of these corals from Mexico and compared it to one from The Bahamas you would say that the two corals are clearly different species. However, in the area in between, there's a continuous gradient of variation so no clear morphological division between the two "species." What seems to be happening is an ongoing speciation event. Several other coral genera including Acropora and Montipora show similar geographic gradients between "species." There also seems to be a fairly high level of hybridization with some of the offspring possibly being fertile. However, since it's hard to define species in corals it's hard to say if these events are truly hybridization or just different ecotypes of the same species breeding.

 

[JHemdal]

I agree with cutegecko - corals are probably not the best example to demonstrate evolution. Like cockroaches and sharks, they've been around too long, relatively unchanged. Explosive speciation as seen in Lake Victorian cichlids is a much better example.

I've always wondered if Darwin ever even looked under the water when he was in the Galapagos. I was there in 1998 and again in 2006 - huge changes there in the corals between those dates. Some sort of white Palythoa was everywhere in '98 (an el Nino year) and I didn't see any in 2006. Same thing for Porites sp. I just figured it was due to the effects of global warming, but who knows - maybe things have normally been swinging back and forth there all this time? Two data points (my two trips) obviously do not make a full study.
Still, there was a recent scientific survey done that resulted with some endemic Galapagos corals as being listed as endangered (on the IUCN redlist?). Since there are no point-source pollution issues, one can possibly assume that the reasons for this decline are due to massive global environmental changes .... I'm scared - how about you?

Jhemdal

 

[danfrith]

There was a pretty good aritcle on reticulate evolution of corals in the "Coral" magazine a year or so ago.

 

[MCsaxmaster]

It depends on what you want to talk about.

As mentioned, Darwin addressed atoll formation in his work, not coral evolution.

Also, scleractinians originated in the Triassic, not the Cambrian. The phylum cnidaria arose in the Cambrian, but those animals were quite a bit different from those living today. Also, the first coral reefs were build by rugose and tabulate corals, not scleractinians. These animals were quite a bit different from scleractinians--much more different than corals are from sea anemones or corallimorphs, for example.

A lot is known about scleractinian evolution, but there are a lot of unknowns as well. I'd pick up a copy of Corals in Space and Time as a primer if you're interested in scleractinian evolution.

Chris

 

[cutegecko3]

20 years ago scleractinians were discovered in the ordovician and the permian.Very recent discoveries in china have pushed them back even further.I havent been able to find any published reports of it yet though.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=12212345#post12212345 target=_blank>Originally posted</a> by cutegecko3
20 years ago scleractinians were discovered in the ordovician and the permian.Very recent discoveries in china have pushed them back even further.I havent been able to find any published reports of it yet though.

Hmmmm, I'm not so sure about that. The first documented examples of scleractinians I'm aware of are from ~ 5 million years after the end-Permian extinction that wiped out the rugosa and tabulata. Rugose and tabulate corals were abundant from the ordivician through permian and built reefs, but scleractinians are absent, to the best of my knowledge.

I'd be very interested to see any documentation of early scleractinians though

 

[danfrith]

Quick question: Is it evolution when Acropora corals chang their shape according to the water flow and change their color according to lighting intensity?

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=12214858#post12214858 target=_blank>Originally posted</a> by danfrith
Quick question: Is it evolution when Acropora corals chang their shape according to the water flow and change their color according to lighting intensity?

No, that's just a bit of phenotypic plasticity. A given species may well be able to alter its physiology a fair amount depending on local conditions, but this will not in any way affect things like fertilization success during a coral spawn.

When looking at speciation in the fossil record, usually we use skelatal characters to tell species apart (same in extant species) knowing that there is a range of variation within any given species. Sometimes it's fairly clear where species lines fall due to skeletal characters, and sometimes it's not so clear. Molecular biology is helping to resolve some relationships here, and muddying the waters elsewhere

Hybridization does occasionally happen though, and that makes some relationships less clear still. For instance, the Caribbean Acropora prolifera is actually just a hybrid of Acropora palmata and Acropora cervicornis, though it has historically been almost as common as either parent species in some places. This is not to say that species-level designations are entirely arbitrary though. There is a fair amount of reprodutive isolation between most species of coral and only limited genetic mixing.

Change over time within a population (or entire species) constitutes evolution. Thus, a single individual cannot possibly evolve, by definition. Speciation can result from evolution and often does if a couple of populations diverge from each other enough.

 

[cutegecko3]

<a href=showthread.php?s=&postid=12212505#post12212505 target=_blank>Originally posted</a> by MCsaxmaster
Hmmmm, I'm not so sure about that. The first documented examples of scleractinians I'm aware of are from ~ 5 million years after the end-Permian extinction that wiped out the rugosa and tabulata. Rugose and tabulate corals were abundant from the ordivician through permian and built reefs, but scleractinians are absent, to the best of my knowledge.

I'd be very interested to see any documentation of early scleractinians though

You can check out an article at jstor.org(progenitors or extinct experiments?)Read the abstract at the bottom of the page.Paleoentology is like everything else,new fossil discoveries are changing things all the time.The problem is it takes along time for it to be widely accepted,and published.

 

[sabbath]

It is hard to prove something that did not happen.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=12216932#post12216932 target=_blank>Originally posted</a> by sabbath
It is hard to prove something that did not happen.

Huh???

 

[sabbath]

<a href=showthread.php?s=&postid=12218402#post12218402 target=_blank>Originally posted</a> by MCsaxmaster
Huh???

The tread is about evolution of corals. As with the thread starters occupation is"Occupation: proving gods inexistence"

I'm not going to get started here. Because this is not the place for this I thought.

But to answer "Huh???"
My theory is corals... started with a designer not an explosion. So I don't believe there is evidence to be found of their evolution. Sure some things adapt to some level but... You know.

Just my .02 Sincerely, Not here to preach just give a one post comment.

 

[MCsaxmaster]

Oh boy...

The tread is about evolution of corals. As with the thread starters occupation is"Occupation: proving gods inexistence"

No one uttered the word "God" until you did, and for a very important reason: the existence or nonexistence of God is utterly irrelevant to the conversation. My work falls within the realm of evolutionary biology. Is my occupation "proving god's inexistence"?

I'm not going to get started here. Because this is not the place for this I thought.

Agreed

But to answer "Huh???"
My theory is corals... started with a designer not an explosion.

That is a religious belief, not a scientific theory. Scientific theories are conceptual frameworks that unite and explain countless facts and laws and consistently make verifiable predictions. Scientific theories are based on evidence. Religious beliefs are based on faith, that is, belief in the absense of evidence.

Besides the Big Bang, which it's quite clear did happen, I'm not sure what you mean by "explosion."

So I don't believe there is evidence to be found of their evolution.

You maintain this belief in spite of clear evidence, not because of it. In science we take evidence seriously, not dogmatic belief.

Sure some things adapt to some level but... You know.

Yup, and populations also show genetic change over time...the definition of evolution

Just my .02 Sincerely, Not here to preach just give a one post comment.

Ha, okey dokey

 

[cutegecko3]

if it was relly based on evidence then why do they still insist dinosaurs evolved into birds.The oldest bird "protavis" is 200 million years old.And the ratio of living forms to extinct forms in the fossil record is 10:1.If evolution and darwins tree of life were true the ratio would have to be at least 1:1,000.So i dont think its possible to prove it,at least not by the current evidece.I was always told that 99.9% of all living things are now extinct but the actual number is only 10%.

 

[seapug]

<a href=showthread.php?s=&postid=12218620#post12218620 target=_blank>Originally posted</a> by sabbath

My theory is corals... started with a designer not an explosion. So I don't believe there is evidence to be found of their evolution. Sure some things adapt to some level but... You know.

Pretty good designer....must have "designed" them to be able to live underwater and live off sunlight, bacteria, and tiny critters and given them the ability to adapt to changing atmospheric conditions and water chemistry that have occurred over millions of years.

The path that they took to survive the time between when your Designer "invented" them and the present day is what Science calls Evolution. Don't be afraid of it.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=12219474#post12219474 target=_blank>Originally posted</a> by cutegecko3
if it was relly based on evidence then why do they still insist dinosaurs evolved into birds.The oldest bird "protavis" is 200 million years old.And the ratio of living forms to extinct forms in the fossil record is 10:1.If evolution and darwins tree of life were true the ratio would have to be at least 1:1,000.So i dont think its possible to prove it,at least not by the current evidece.I was always told that 99.9% of all living things are now extinct but the actual number is only 10%.

Oh good lord.

1) Protavis is not generally accepted as an early bird. It may or may not be closely aligned with Aves. It was clearly feathered and analagous to early therapods. Lots of therapod dinosaurs, we now know, had feathers though. Protavis at the very most would push back the split between aves and dinosauria, it wouldn't negate the common ancestry.

Even so, what does that have to do even remotely with coral evolution?

As for the ratio of living species to fossil species: do you have any idea of the unliklihood of fossil formation? OF COURSE we don't have fossils of every species that has ever lived. Many species simply don't fossilize well, and we haven't even begun to search the entire planet for fossils. The fossil record is amazingly good, and clearly demonstrates evolution. Only through complete ignorance of the fossil record could a person suggest otherwise.

No one considers species level designations when describing large patterns of evolutionary change for good reason: species come and go too fast on the geologic timescale to give meaningful results. Considering taxonomic levels at and above genus it's clear that most forms that have ever existed (~98-99%) are now extinct. Geologic time is very, very long. Natural selection has brought about many, many natural experiments. The ones that show up in the fossil record work for a time, but most fail sooner or later.

But again, what does this have to do with coral evolution?

Chris

 

[greenbean36191]

Guys, lets get this thread back on track or it will get closed very quickly. It would be a shame to cut an interesting topic like this short and prevent the OP from getting the help he/she came for. While I would love to address some of the points brought up here myself, it's against RC policy to discuss topics of religion since it tends to breed bad blood among members.

If you would like to discuss the scientific basis for evolutionary biology or some perceived lack thereof, feel free to do so, but start another thread and leave religion out of the discussion. Failure to do so will lead to quick closure of the thread and likely warnings from mods.

Now back to the evolutionary history of corals...