Naked Science Forum

Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: Andrew Askew on 28/09/2009 17:30:03

Title: Does air oxygen concentration limit animal size?
Post by: Andrew Askew on 28/09/2009 17:30:03

Andrew Askew asked the Naked Scientists:
   
Is the content of oxygen in the air a limiting factor in the maximum size of land based animals? Was the air oxygen rich during the reign of the dinosaurs partially explaining the immense size of the sauropods (amongst others)?

Love the podcasts (http://www.thenakedscientists.com/HTML/podcasts/) by the way. I have just started trying to catch up from 2005!!!!!

What do you think?

Title: Does air oxygen concentration limit animal size?
Post by: RD on 28/09/2009 18:17:57

The Jurassic (http://en.wikipedia.org/wiki/Jurassic) period was warmer and had higher levels of carbon dioxide than today, so more vegetation => bigger herbivores possible.

(There was more oxygen too: oxygen is the waste product of plants)

Title: Does air oxygen concentration limit animal size?
Post by: RD on 29/09/2009 06:25:25

The biggest animal that has ever lived is alive today: the blue whale, despite our current lower concentration of atmospheric of oxygen than in the Jurassic period.

Quote

... Interestingly, there is no significant correlation between atmospheric oxygen and maximum body size elsewhere in the geological record.

http://en.wikipedia.org/wiki/Geological_history_of_oxygen

Title: Does air oxygen concentration limit animal size?
Post by: Nizzle on 06/10/2009 16:35:04

Higher concentration of oxygen would allow an increase of size in creatures that use oxygen in a poor manner, ie insects.
There was an era before the dinosaurs, where oxygen levels were 40% higher than today, and in this era, insects (or more accurate arthropods) could grow to sizes you would nowadays only see in horror flicks.