3
$\begingroup$

Vascular plants have vascular tissues that passively allow water and nutrients to flow up between the different organs of the plant. Could a similar tissue be useful alongside animal tissues? It seems like it should work, as this extra transport method would be very useful in extending the range of nutrients from blood vessels, but I may have missed some flaw

Are there any issues with vascular tissue existing in animals?

$\endgroup$
5
  • 5
    $\begingroup$ animals already have vascular tissue, arteries, veins, lymph ducts. $\endgroup$
    – John
    Commented Sep 18, 2021 at 22:41
  • 1
    $\begingroup$ @John the circulatory system is not like plant vascular tissue, and is not a distinct tissue type $\endgroup$ Commented Sep 18, 2021 at 22:43
  • 3
    $\begingroup$ and how exactly do you think it is different? keep in mind the vast spectrum of circulatory systems in animals. also vascular tissue is a an animal tissue type $\endgroup$
    – John
    Commented Sep 18, 2021 at 23:04
  • $\begingroup$ "This extra transport method would be very useful in extending the range of nutrients from blood vessels": assumes facts not in evidence. It what way would vessels made of different materials have any influence on the contents of the fluid circulating in those vessels? (Unless you mean the mode of propulsion by cohesion-tension of the raw sap in xylem vessels. But that has nothing to do with the vessels themselves, which are just dumb pipes.) $\endgroup$
    – AlexP
    Commented Sep 19, 2021 at 0:52
  • $\begingroup$ Now this is an interesting question! A proper geopoetical query! $\endgroup$
    – elemtilas
    Commented Sep 19, 2021 at 4:41

2 Answers 2

0
$\begingroup$

Neither Plant Nor Animal...

Some preliminaries:

  1. Typical animal vascular systems are active -- some kind of muscular body pushes fluid throughout the animal's body via some kind vascular system
  2. Typical plant vascular systems are passive -- the tubes that draw fluid in from the earth are open at the top there's some kind of pressure differential that draws the fluid up. Presumably with hanging plants, gravity plays a role too.

Two questions:

  1. Will it work? One of your questions is essentially one of function. I concur with you that there is no real reason it shouldn't work. If it's there in the creature, it will function. It'll function because it's there. It's just a matter of evolving a system of vascular tissue that doesn't rely on an active pump to do its work, and that is happily outside the scope of your question! I could see this kind of system evolving in a plantimal, a kingdom of living being that is neither plant nor animal but combines traits and characteristics of both. I could see a passive vascular system evolving to become a thermoregulation device. Perhaps a warm water reservoir in the core could be connected to a passive vasculature that would slowly bleed off the water and its heat. I could see it being used in a very plant-like way of getting certain nutrients directly from the soil through rootlike "hairs" on the plantimal's limbs.
  2. Will it be of benefit? The other question speaks to utility. Nature seems to abhor useless structures. Obviously, if some kind of lifeform had two different kinds of vascular system, there must be a good reason for it, and it must be of some kind of benefit. The real question becomes, then, not "will it benefit" but rather "who would it benefit?"

Issues & Problems:

I don't think there is any insurmountable issue, problem or flaw with the concept of passive and active vascularity coexisting within the same organism. The only issue I'd have is the prescription that the organism must be an animal. On that point, I'd have to beg clarity: by "animal" do you mean an ordinary terrestrial animal that you'd like to see evolve some plant-like characteristics; or do you mean some non-terrestrial animal-like proto-creature whose evolutionary path is already moving in the plantimal direction?

$\endgroup$
2
  • $\begingroup$ plenty of animal systems are passive, especially in small animals. $\endgroup$
    – John
    Commented Sep 19, 2021 at 23:24
  • $\begingroup$ @John -- feel free to either elaborate or edit! $\endgroup$
    – elemtilas
    Commented Sep 20, 2021 at 0:48
5
$\begingroup$

It better be good

Blood vessels do not only transport things. They contain all kinds of agents, consuming the nutrients, or breaking down certain agents, like the immune system does. Plasma is 90 percent water already and makes up more than half of total blood volume. Other 10 percent is protein molecules, including enzymes, clotting agents, immune system components, plus other body essentials such as vitamins and hormones.

http://givingblood.org/about-blood/blood-components.aspx

Water contains less active components. It behaves more neutral, it would just transport stuff dissolvable in water. If you could dissolve some of blood's functional components in water (like plants have in their water channels) your water vascular channels could take over part of the arteries functions. But it would also resemble blood.. and the animal would need separate hearts, to let it work. The heart pump transporting blood takes a lot of energy already.. 2 hearts would take the double amount.

https://openoregon.pressbooks.pub/bodyphysics/chapter/human-metabolism/

It's used for waste disposal

In the animal body, the intestinal tract serves as a water channel too. Urine is 91% water, the kidneys use blatter and urethra to transport it out. Gravity and some muscular pressure take care of that, it does not need a continuous circulation. Another water channel animals have is: sweat glands in/under the skin. They serve to transport water and waste out. They also serve as coolants, the water evaporates.

https://en.wikipedia.org/wiki/Urethra

https://www.sciencedirect.com/topics/medicine-and-dentistry/sweat-gland

$\endgroup$
4
  • 1
    $\begingroup$ What do you mean by "pores in the skin"? Are they the same thing as sweat glands? $\endgroup$
    – AlexP
    Commented Sep 19, 2021 at 0:52
  • 1
    $\begingroup$ Yes, I used Google Translate from Dutch. Thx, I'll change the text. Sweat glants is also a better more general term for it. $\endgroup$
    – Goodies
    Commented Sep 19, 2021 at 0:54
  • 2
    $\begingroup$ P.S. The urinary bladder is not connected to the intestinal tract. Urine is produced by the kidneys by filtering the blood. $\endgroup$
    – AlexP
    Commented Sep 19, 2021 at 0:56
  • $\begingroup$ I hope the second part is readable now, thanks for the assist. $\endgroup$
    – Goodies
    Commented Sep 19, 2021 at 1:09

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .