TuxLife

[erez87]

BTW don't keep old species around. Old species don't tend to stick around. The "simple" creatures of today (well except for sponges and jellyfish, but maybe even including those) are more complex creatures losing traits to become simplified. For example Flatworms who have no inner body cavity are apparently phylogenetically inside the more complex groups (which means their ancestors used to be more complex and lost traits).

And yes, as long as my guys survive, I try to branch.

 

[Lord_Iggy]

That's not a good reason for keeping or refusing to keep 'old' species around. While it's true that endoparasitic flatworms have lost some of their complexity, it's only because their environment has changed radically from that of their possible free-living ancestors, making the possession of a digestive tract and sensory organs largely unnecessary and a waste of energy to grow and maintain. All they need to do is absorb nutrients from the intestines of larger animals and produce reproductive cysts like there's no tomorrow.

Physiological complexity goes up and down based on whatever happens to provide competitive advantages in given situations. Frequently 'old' species have been around for a very long time because they are optimally adapted for their environment. How long they have existed in that niche is unimportant, except for stochastic extinction events which may clear them from their entrenched positions and open up niches for new species- naturally the longer a species has been around, the more likely they are to be around to experience a mass extinction event that will threaten their population. However, this is true for all species. At any given time, any species has a chance of suffering chance extinction- indeed, more complex creatures tend to be more vulnerable to dramatic upsets in their environment, while simpler species can rebound with great success.

Regarding your examples of Porifera (sponges) and Cnidaria (anemones/jellyfish/siphonophores), they have existed with only relatively minor structural changes over the better part of the last billion years, they didn't gain or lose complexity in any sort of major trend- they merely varied up and down in structural complexity to best meet the competitive challenges provided by their environment. Even today you'll find huge variations in sponge structures- from extremely simple asconoid sponges, which are basically just hollow chambers, to the more elabourate syconoid and leuconoid sponges which possess interiors that border on the downright maze-like.

 

[spaceman98]

Sharks, Sponges, Jellyfish, Algae the list goes on. Really, I would say that old species have survived in many cases. However, that is not the case if, for example, two species compeate for top predator or a scarce resource. In both cases, only one usually survives.

 

[Boundless]

BTW don't keep old species around. Old species don't tend to stick around. The "simple" creatures of today (well except for sponges and jellyfish, but maybe even including those) are more complex creatures losing traits to become simplified. For example Flatworms who have no inner body cavity are apparently phylogenetically inside the more complex groups (which means their ancestors used to be more complex and lost traits).

And yes, as long as my guys survive, I try to branch.

Nonsense. There are as many ancient things as "new ones". If a niche still exists it can survive. Rarely should a new evolution destroy its elder, it merely moves into a new favorable niche, leaving the previous one behind untouched. There might not be as many of the older species, but it will live on for a long time.

 

[erez87]

Nonsense. There are as many ancient things as "new ones". If a niche still exists it can survive. Rarely should a new evolution destroy its elder, it merely moves into a new favorable niche, leaving the previous one behind untouched. There might not be as many of the older species, but it will live on for a long time.

Nonsense. Show me an ancient creature that was simple and remained simple except for Jellyfish and Sponges.

Iggy. Yes. I study Biology too. I like phylogeny. There aren't true simple creatures other than Cnidaria and Porifera, and there are theories saying even they are simplified bilaterians.

 

[Lord_Iggy]

Basically every single celled prokaryote and eukaryote has remained unchanged in their level of complexity. That's a poor term to use anyway because it's not clear- do you mean genetically or physiologically simple? Flatworms have remained relatively simple, most arthropods have not increased in complexity since the Paleozoic, and fish seemed to have reached near-modern body forms only shortly thereafter.

At any rate, I think we could agree that while some very ancient groups go extinct, there are some who do not, and that is ultimately the point I am arguing for. I suspect that having very simple species go extinct would not turn out well in this evolution-game, because people are loathe to make their creatures more simple, even if it would make them more successful.

 

[erez87]

http://en.wikipedia.org/wiki/Myxozoa a single cell multicellular animal. Closer to Cnidaria than Sponges which means it's single cell among the multicellular.

I said the words creature and animal on purpose, since I meant animals not bacteria or plants etc... We cannot know about them if the simpler ones have always been simple or simplified in time.

I mean physiologically complex btw.

 

[spaceman98]

Crinoids, Sea pen, Equisetum (Horsetail plant) the list goes on...

 

[erez87]

Crinoids, Sea pen, Equisetum (Horsetail plant) the list goes on...

What makes you think these came from simple creatures? Echinodermata are a simple form of life in the middle of many more complex ones hinting their evolution from more complex creatures. They used to be bilaterians and lost that trait.

Sea pens are Cnidarians, which are still unsure if they are evolved from simple creatures or from more complex ones, losing complexity in return for simplicity.

And I said animals, not plants.

Anyway, update, Me wants

 

[spaceman98]

Crinoid fossils have been found since the cambrian period. (same for Jellyfish and Sponges)

 

[erez87]

Crinoid fossils have been found since the cambrian period. (same for Jellyfish and Sponges)

That does not mean they didn't evolve from more complex triploblastic creatures.

 

[Terrance888]

That does not mean they did evolve from more complex triploblastic creatures.

 

[filli_noctus]

I would tend to agree with Boundless' opinion here. Daft's suggestion sounds like a good one as well- perhaps a bonus for the living species that has the most different branches descending from it? Right now that would be the Tailus, with 4 branches, 3 if you only count extant species.

The problem with this suggestion is that it rewards the person who created the original creature, not those who branch from it. Perhaps a better idea would be a branching award for the most successful creature evolved from another players creature.

 

[erez87]

The problem with this suggestion is that it rewards the person who created the original creature, not those who branch from it. Perhaps a better idea would be a branching award for the most successful creature evolved from another players creature.

Or just the person who branched the most.

BTW All except for 1 branch in the Tailus family are my creations thank you very much.

 

[Lord_Iggy]

I'm not sure that your arguments really support your thesis that today's simple animals had more complex ancestors. To me, it seems just as likely that they reached a certain level of physiological complexity and then remained in that comfortable niche.

I'm not arguing that organisms don't change in simplicity or complexity. Myxozoa is a good example of a single-celled organism closest in relation to Cnidarians- similarly HeLa and Jurkat cells are single-celled organisms derived from humans. However, suggesting that all simple animals have more complex ancestors is just unsubstantiated.

Regarding echinoderms, who's to say that pentaradial symmetry is more or less advanced than bilateral? Their larvae are bilateral, yes, but that doesn't mean that they are simpler than their possible bilateral ancestors.

 

[erez87]

My point is:

In Red are all the animals that are simpler than their ancestors in lifestyle and mostly physiologically. Yellow are their more complex ancestors.

What is a simple animal (and when I say simple, I mean something around the lines of the Tailus, who is more akin to flatworms than fish - and which will, if given the chance, evolve into the whole Deuderostomia line eventually, plans will be plans) that evolved out of a simpler animal and remained alive? Most if not all Simple animals today are not super survivors from early evolution (they aren't basal) but other more complex survivors that turned simple once the true simple ones died out of competition.


I only say all this because people sometimes say the MOD should keep ancient simple animals because they are kept in reality, when they really aren't. Simple animals should arrive from the complex winners once the niche is open again, not any other way.

 

[Lord_Iggy]

The problem here is that you're cherrypicking data, and also making assumptions on certain relationships where the jury is still out.

Placozoa appear to be basal to the eumetazoa and there are competing theories on their ancestry. Some suggest that they likely diverged before cnidaria and myxozoa, others, like yourself, suggest that they are eumetazoans which have undergone secondary losses of features. There is ultimately a lack of compelling evidence in either direction in that case.

Creatures similar to flatworms may be the common ancestors of molluscs and arthropods, which would render your flatworm arguments null. Are you basing your division of platyhelminthes into two groups on Wallberg et al. (2007)? You may need to rethink where you've placed those groups, as this article suggests that they are indeed basal.

You've not provided any argument that tunicates are anything other than descendants of early chordates. Their fossil record dates back to the Cambrian, so the possibility that they have a more recent origin with significantly more complex chordate ancestors is exceedingly slim.

My statements on myxozoa and echinodermata stand- myxozoa has undergone drastic simplification due to becoming an obligate parasite, and echinoderms are not obviously simpler than their bilateran ancestors.

Ultimately, these points are unimportant, however. You aren't convincingly supporting your hypothesis that all simple animals today are non-basal. You're just using examples of animals that have more physiologically complex relativess, and many of your cases lack evidence to support them.

 

[spaceman98]

Update?

 

[Lord_Iggy]

I'm certainly looking forward to it!

 

[Lord_Iggy]

So, Tuxedo, what's the schedule looking like for you right now?