Theory on origin of animals challenged

Hi ATS!
I stumbled into this study today, I tried to do a search but I found nothing.

The Theory

One of science's strongest dogmas is that complex life on Earth could only evolve when oxygen levels in the atmosphere rose to close to modern levels. But now studies of a small sea sponge fished out of a Danish fjord shows that complex life does not need high levels of oxygen in order to live and grow.

The origin of complex life is one of science's greatest mysteries. How could the first small primitive cells evolve into the diversity of advanced life forms that exists on Earth today? The explanation in all textbooks is: Oxygen. Complex life evolved because the atmospheric levels of oxygen began to rise app. 630 – 635 million years ago.

However new studies of a common sea sponge from Kerteminde Fjord in Denmark shows that this explanation needs to be reconsidered. The sponge studies show that animals can live and grow even with very limited oxygen supplies.
In fact animals can live and grow when the atmosphere contains only 0.5 per cent of the oxygen levels in today's atmosphere.


Read more at: phys.org...

It didn't surprise me that much, but I must admit that it is really fascinating that animals can grow and live with only 0.5 per cent.

A little over half a billion years ago, the first forms of complex life - animals - evolved on Earth. Billions of years before that life had only consisted of simple single-celled life forms. The emergence of animals coincided with a significant rise in atmospheric oxygen, and therefore it seemed obvious to link the two events and conclude that the increased oxygen levels had led to the evolution of animals.
"But nobody has ever tested how much oxygen animals need – at least not to my knowledge. Therefore we decided to find out", says Daniel Mills.


Read more at: phys.org...

I don't understand why nobody have ever tested how much oxygen animals needs?
Maybe a ATS member can shed some more light on it?

What do you guys think about this? I find it pretty interesting, but as I said it does not surprise me at all. But I guess that the more oxygen there is in our atmosphere back then, the more the animals could evolve.

Oh and I forgot to add that in our danish newspaper, the headline goes like this "Danish findings may increase the chance of life in space"

I cant understand where the oxygen came from, never mind the sponge

reply to post by ypperst


The Cambrian explosion came within about 100 million years of the end of a period of intense global glaciation and as the earth warmed up life proceeded from the simpler form's but here is another crux to consider, the earth is aged by scientists based on isotopic decay at about 4.25 billion years old and may have had liquid water and a solid crust from about 3.9 billion years ago, now it is a mystery but isotope traces indicate life was extant in some form from at least 3.9 billion years ago, about 2.25 billion years ago the earth may have almost completely frozen with only deep water vent's and there attendant chemosynthetic life form's surviving as the earth suffered intense glacial periods with possible warmer intermediate periods until that 750 million years ago.
Maybe complex life existed long before somewhere in the window of opportunity from when life apparently first arose at 3.9 billion years ago to the start of that glacial period at 2.25 billion years ago but the argument often quoted against is that there was insufficient atmospheric oxygen based on geological sample's and as those samples are unreliable at best I suspect it did, the description of the biology of the roswell aliens if real would suggest a terrestrial origin but no one our current life tree.
Personally though I do believe in god.

reply to post by borntowatch


For one thing. Oxygen is liberated slowly from mechanical action of water. If left long enough, the ocean waves will tease oxygen out of the seas. Anaerobic bacterium also can create free oxygen from sulfur dioxide, etc. And my favorite, photosynthesis from green organisms.

ypperst
It didn't surprise me that much, but I must admit that it is really fascinating that animals can grow and live with only 0.5 per cent.

Sponges are so unlike other animals we didn't even know they were animals when they were first discovered...some thought they were plants:

Sponges

Sponges are among the most unusual animals

because of lifestyle and appearance originally thought they were plants; especially since some are green due to commensal algae

The fact they are so unlike other animals leads me to think that theories about other animals shouldn't be highly threatened by finding differences with sponges. We already knew they were different, now we suspect they might be different in yet one more way.

InverseLookingGlass
reply to post by borntowatch

 

For one thing. Oxygen is liberated slowly from mechanical action of water. If left long enough, the ocean waves will tease oxygen out of the seas. Anaerobic bacterium also can create free oxygen from sulfur dioxide, etc. And my favorite, photosynthesis from green organisms.

wow that amazing I am nigh on speechless, nigh on


Where did the water come from
Where did the Anaerobic bacterium come from
Where did all the rest of the stuff come from (sulfur dioxide, photosynthesis)