Planimal

[Kehgrehdid]

I'd meant it as more of a similar low-density energy source, not a direct analogue. And if it was a smaller animal, it could get get away with the lower efficiency, the way that cows have to be constantly eating grass, but small rodents can afford to spend a greater percentage of their time on the move.

[Wanderer]

Which still doesn't change the fact that photosynthesis is so much less efficient than whatever you named there, that it is not a valid comparison. Being small just doesn't make up for it.

You're not going to get a plant that moves anywhere near as efficiently as those specialized cars that use solar energy. Combine that with the biological fact that photosynthesis is horribly inefficient compared to just about any way of acquiring usefull energy and you end up with the fact that mobile plants are impossible.

Off course creatures in your conworld don't have the be realistic in any way. You can even come up with some sort of justification for how these things came into being, just realize the attempts to justify the existing of mobile plants posed in this thread are not in the least realistic.

[KiKi Tampusa]

cough (kill joy)

[Kehgrehdid]

Okay, then, suppose it wasn't a pure autotroph, but also ate stuff, like a desendant of the Venus' flytrap, where its predatory nature eventually allowed it to eat enough to move.

[Wanderer]

Maybe......

Venus' Fly traps don't digest as fast as animals do, which, I suppose, makes the rate at which they gather energy much too slow to be able to move arround properly. Apparently when they catch something in one of their traps, they take about 10 days to digeste it before the trap can be used again.

Basically, plants are optimized for growing. A defining feature of plants is that they do not move.I'm not very knowledgable on biology or on the evolution theory, but it seems very doubtful to me that any plant will ever evolve to be mobile, because they are simply optimalized for living whilst staning still.
There are more problems than just the ammount of energy. They would need to get a way of getting enough energy, they would need a way for being able to transport the energy fast enough, they would need to lose their roots, they would need to grow limbs that move them arround, they would have to develop a kind of muscle tissue, they would have to develop senses or at least some sort of way to gather information from their environment, they would need a way to process that information, they would need a kind of brain to coördinate their movement.

If you've come up with a plant that does all of these things, you've just come up with an animal, but you call it a plant.

[Rik]

Any of the attempts to justify 'planimals' made in this thread fail. It is impossible for a plant to gather anywhere near enough energy to be mobile.

You need to either forsake biology and just go with some fantasy/mythical creature or forget about planimals.

Nonsense - such creatures already exist in the real world. Not forgetting various corals and giant clams.

As for my conspecies, only the sessile forms rely on photosynthesis to meet all their energy needs; the motile forms possess chloroplast equivalents in their cells, but are mainly heterotrophic.

[Wanderer]

I am astounded and perplexed and shall take back every word I said in this thread about photosynthesis not being able to produce the ammount of energy that is required to be mobile.

Good luck in designing conseaslugs. :-P

It's still not a plant with animal like qualities though, it's an animal that can do photosynthesis, one can wonder, is that enough to be called 'plant-based'.

[clockworkbanana]

Well, I know that carnivorous plants don't digest their food to get energy, as such, but to gain nutrients they can't get from the soil (but still need).So, with some tweaks, the plant could digest things to gain energy, and have a rudimentary system of movement. The only sense they would need is one for light to move toward it, and touch, to move away from things trying to eat it. Both of these could be very basic feedback loops, like those found in jelly fish (at the most complex).

[KiKi Tampusa]

Maybe the animal is nocturnal sleeps in the sun during the day and does whatever at night. Also this could also be a fusion
I watched the show Darwin 4 and this creature evidently gets a good amount of energy from trees that grow on its back. They pump sugar into him and he gives nutrients to the trees.

[Ainuke]

I suppose all you need is an animal that collects sunlight through something on it's back, and drinks water.

[KiKi Tampusa]

Now I do not think that we have looked at the possibilities. This sea slug actually is a great example. Though I must say, if the slug became equally plant and animal, you could kick out a respiratory system. The plants would oxygenate the animal part and the animal could supply carbon dioxide to the plant. It would only eat in youth to gain nutrients. A “stomach” could have bacteria that could process the waste and return it all to the plant and animal. This sounds a lot like a space faring beast. A lot like a space faring thing. It would solve a lot of problems like air and food. Mining asteroids and comets would allow the beast to grow larger. The beast could also jettison something for propulsion. This was originally to be land animals but this works.

[Crumbs]

You could kick out a respiratory system. The plants would oxygenate the animal part and the animal could supply carbon dioxide to the plant.

Eh, not quite. See, even though plants photosynthesize, they also use cellular respiration. 6CO2 + 6H2O + Light (energy) → C6H12O6 + 6O2. However, the whole point of getting glucose is so they can turn it into energy that they can use. ie, C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP (energy). So plants are already this ideal self-contained organism you're looking for. The only reason that they produce oxygen at all is because photosynthesis is ever so slightly more efficient that cellular respiration. However, even this is almost balanced out, because plants can't photosynthesize too well at night.

As for the rest of your idea, I dunno. Maybe, put it would need some serious structural reworking.

[Yačay256]

No one has yet mentioned the Edicarian Biota, which some scholars believe to be somewhere between plants and animals?

[teh_Foxx0rz]

Here you go :-)