Is Bigger Really Better?

Ask any of the lady biologists out there and I am sure they will tell you that bigger is better. However, most men would argue that it isn't necessarily the size that matters, instead it depends on how well the animal forages. I mean lets face it, survival of the fittest doesn't segregate by size, but I'm still thinking the women are on to something here. Let's take for instance our scaly (possibly feathery) friends the dinosaurs.

Dinosaurs walked the earth for thousands of years, and grew to massive sizes. For example, the well known Apatosaurus (formerly the brontosaurus), grew to 35 meters in length and up to 26 tons. This creature isn't even the biggest sauropod discovered. The Argentinosaurus grew upwards of 100 tons and reached lengths of about 40 meters and still didn't top the charts. Its not to be taken lightly, the incredible size these organisms grew to become. Now here comes the big "BUT." But why did these sauropods grow to such great sizes. What is the reason they evolved to tower in their environments. We know not all dinosaurs grew to such great stature so what is the reasoning?

Like most hypotheses there are plenty out there including gravity differences from then and now; how dinosaurs used the energy they consumed; and finally a coevolution between predator and prey. All of which I feel deserve a little discussion in this post.

First off, millions of years ago the Earth was smaller. Geologists have discovered this and I wouldn't argue in opposition. A smaller earth would therefore have a lower gravitational pull. Another valid point that I would not contend against. I just do not believe that dinosaurs would grow to such enormous sizes just because of less gravity. I am going to leave it at that because I think the other to hypotheses are far more likely.

The second theory has to do with the way these sauropods expended there energy. During the Mesozoic area the environment was abundant in plants to sustain large animals. Sauropods were able to obtain immense amounts of energy in the "all you can eat buffet" around them. Now I also want to add about the 'heated' debate on wether or not dinosaurs were warm or cold blooded. One man, a Dr. Brian K. McNab from the University of Florida, is suggesting a homeothermic body climate for dinosaurs. What this means is that dinosaurs were neither warm blooded or cold blooded but somewher in between. A warm blooded animal, humans and other mammals, must use the energy the consumed to keep themselves warm. Cold blooded animals, such as amphibians and reptiles, has their heat regulated by the environment around them which fluctuates and energy is used to regulate this. So the idea that dinosaurs have a homeothermic body climate would mean that the energy they consumed could be used for growth. This would account for why some dinosaurs were able to grow so big.

The last popular theory is that of coevolution between predator and prey. This is a classic case of
evolution that could explain the increased size of dinosaurs. The easiet prey for a predator would be the smallest and weakest. With these small, weak dinosaurs out of the picture the larger, more powerful dinosaurs would breed to produce large, and powerful offspring. Likewise, the predators ability to attack its prey comes from the fact that they can take their prey down. This would mean that if a predator was not big enough or strong enough to take its prey down then it will not be getting a meal and most likely die off .This leaves the larger predators who could hunt and feast to breed and produce offspring that is bigger and more powerful. This coevolution goes back and forth creating dinosuars in massive sizes.

Like I said these are all hypotheses, backed up by some scientific facts of course, which is why they are such popular ideas. Although some seem more likely than others, none of these have solid evidence to prove them correct. It's completely possible that all were factors in the growth of dinosaurs, but it is just as plausible that not one of these factors contributed. Discovery is what motivates many scientists and I am sure more ideas have and will come about as to why these creatures grew so big.

For those wondering what the largest dinosaur ever discovered is, it is the Amphicoelias. This massive sauropod has been found at lengths of up to 60 meters and a mass of around 220 tons. In case it isn't obvious that is BIG.

"Was Weaker Gravity Responsible for Larger Dinosaur Size?" Earic.com (n.d.): n. pag. 27 Feb. 2013. Web. 21 Oct. 2013.

Rettner, Rachael. "How Dinosaurs Got So Big." LiveScience.com. LiveScience, 06 July 2009. Web. 21 Oct. 2013.

"Why Were Dinosaurs so Big?" Dino Dinosaurs. N.p., 02 Dec. 2012. Web. 21 Oct. 2013.