I've read this plenty of places, and even those creatures that rely on chemeosynthesis (chemosynthesis?) still need the sun. So could someone tell me if this is true or what the actual little phrase is. Thanks.
All multiceluar organisms require sunlight
- Thread starter Betrayer0fHope
- Start date
Man I thought it was spelled multicellular but my spellcheck failed to perform as I wished. Sorry guys.
Last edited by a moderator:
I think you're right draq. So, is it all "complex" life on earth needs sunlight? Or what?
Ask the question differently: is there any higher organism that does not need oxygen? An anaerobic multicellular organism?
Do all multicellular organisms require sunlight?
Answer: No.
There are hydrothermal vent ecosystems on the bottom of the ocean that sustain numerous species of complex multicellular organisms, such as tube worms, crustaceans and small fish. These animals rely on chemotrophic bacteria as the base of their food chain. These small ecosystems do not require any input from the Sun as the bacteria that form the base of the food chain derive their energy from compounds emanating from the vents.
Do all multicellular organisms require oxygen?
Answer: No. (At least, not all the time.)
Facultative anaerobes can function in the presence or absence of oxygen. For instance, organisms that live in the intertidal zone, such as the bivalve Mytilus, can function aerobically, using gills when they are under water and anaerobically when exposed to the air. Such organisms display habitat-dependent anaerobic functioning, or habitat-dependent anaerobiosis. Muscles in most animals display activity-dependent anaerobiosis, meaning that they can function anaerobically for short periods. For example, when animals perform bursts of intense exercise, their ATP needs rise faster than the ability of the body to provide oxygen to the muscle. The muscle functions anaerobically until the lactic acid builds up to the point at which the fall in pH inhibits the anaerobic pathway.
Source: Biochemistry (5th Ed), Berg et al.
Answer: No.
There are hydrothermal vent ecosystems on the bottom of the ocean that sustain numerous species of complex multicellular organisms, such as tube worms, crustaceans and small fish. These animals rely on chemotrophic bacteria as the base of their food chain. These small ecosystems do not require any input from the Sun as the bacteria that form the base of the food chain derive their energy from compounds emanating from the vents.
Do all multicellular organisms require oxygen?
Answer: No. (At least, not all the time.)
Facultative anaerobes can function in the presence or absence of oxygen. For instance, organisms that live in the intertidal zone, such as the bivalve Mytilus, can function aerobically, using gills when they are under water and anaerobically when exposed to the air. Such organisms display habitat-dependent anaerobic functioning, or habitat-dependent anaerobiosis. Muscles in most animals display activity-dependent anaerobiosis, meaning that they can function anaerobically for short periods. For example, when animals perform bursts of intense exercise, their ATP needs rise faster than the ability of the body to provide oxygen to the muscle. The muscle functions anaerobically until the lactic acid builds up to the point at which the fall in pH inhibits the anaerobic pathway.
Source: Biochemistry (5th Ed), Berg et al.
Bacteria are unicellular.
the phrase that you might be looking for is "all of the earths energy comes from the sun".
I was aware of this (by the way I have the same book but 4th addition) I'm asking for a multicellular organism the is completely anaerobic, as the ecosystems of hydrothermal vents still require photosynthesis provided oxygen to metabolize chemosynthesised food.
Enmos
Valued Senior Member
I must be misreading this..
Ecosystems around hydrothermal events do not require photosynthesis, there isn't even any light to begin with.
Also, oxygen tends to be poisonous to those creatures.
Edit: Ok, I see what you meant. The multicellular organisms still require oxygen.. and that oxygen comes eventually from photosynthesizing plants.. alright.
Last edited:
I not one to teach lessons on ecology, so I will repeat my self slowly and methodically:
1. We assume any multicelluar life form most probably of the Animalia is aerobic, until evidence of a fully anarobic one can be provided.
2. All oxygen in earth's ecosystem comes from photosynthesis, unless evidence is provided for an exception.
3. We are talking about multicelluar life form living by consuming the chemosynthetic bacteria (or their products) which live of the hydrothermal vents. By reasoning 1 and 2 they are still living of the products of photosynthesis (oxygen) and thus aren't independent of it. Now if you can prove otherwise please do: I much rather hear of a complete chemosynthetic ecosystem than some oxygen breathing critters living off the scum that grows from volcano gas.
Enmos
Valued Senior Member
See my edit
Fact remains that these organisms do not directly need light. But I see the point the OP wanted to make now.
See, the thing that got me thinking was that scientists discovered that those animals at the bottom of hydrothermal vents need oxygen, and without the sun there wouldn't be too much oxygen to go around. Maybe some knowledge has changed since the 2005 article.