Have you ever wondered why the species from the dinosaur era were much larger compared to the species that exist today? Why do some species tend to be larger than others? The size of a specie is one of the most essential characteristics that resemble how a specie should live. Various perspectives regarding the size of species depending on the climate have been introduced by numerous scientists. It is a very controversial topic to review but, I intend to summarize my findings and would be delighted to know about how others believe climate change and global warming will have impact on the size evolution in the near future.
I will begin by reviewing the discovery of a 60-million year old fossil believed to be a snake that weighed approximately 1140kg and measured 13 meters in length. This magnificent fossil referred to as the “Titanoboa cerrejonensis” was uncovered by the University of Florida’s Florida Museum of Natural History and a crew directed by the Smithsonian Tropical Research Institute. Soon after the discovery, the fossil was examined by Jason Head from the University of Toronto-Mississauga who made the estimates of the approximate temperature of Earth 60-million years ago (the period in which the Titanoboa cerrejonensis lived). Scientists believed that only a very hot climate would be enough to support cold blooded creatures such as this snake. Paleontologists stated that cold-blooded reptiles tend to be larger when they live in a hot climate as correlation studies indicate that as temperature rises, the upper body of poikilotherms which are cold-blooded creatures also increases in size proven by the size of their bone structure. So exactly how much hotter would the Earth have to be to support a snake as big as this? It is believed that tropical ecosystems that supported creatures such as this snake lived in rain forests such as Cerrejon at an average temperature of 32 degrees Celsius which is approximately 5 degrees Celsius higher than the average temperature of a modern rain forest. As a matter of fact, Jason Head from the University of Toronto and Jonathan Bloch from Florida Museum of Natural History indicated that the Titanoboa cerrejonensis required a minimum average temperature of 30-34 degrees Celsius to survive.
The Titanoboa cerrejonensis fossil vertebra is placed alongside the vertebra of a modern day, 10-foot-long boa constrictor. The two vertebrae are both positioned near the snake’s bellies. -Jason Head et al.
Now some of you reading this may say this has not proven or has given any reason to why animals in the dinosaur era used to be a lot bigger than the modern days’ creatures. This is where the real scientific explanation begins. Scientist believe that the main reason for massive and enormous size of species were due to the flourishing atmosphere that contained an immense amount of oxygen and carbon dioxide. As a matter of fact, the level of oxygen was 50% higher while the carbon dioxide was at the limit of 500% compared to today. Oxygen and carbon dioxide are two of the most important components that help plants grow faster and larger. With such hot conditions, not only oxygen and carbon dioxide was abundant but, hard rain and sunlight would also be very constant. In an environment and atmosphere such as this, not only the ordinary plants we see today may have been much larger but, various unknown plant life may have been abundant. I myself, even come to believe that some form of plants may have given unreal yet rich nutrients to these species, helping the species in the dinosaur era to develop much quicker and grow bigger. We cannot be sure what these unreal plants may have been, it may have not even existed as it is a personal statement unapproved by scientific evidence. Yet, I would still like to include such statement because we do know for a fact that the ecosystem at the dinosaur era was a lot different compared to the one we live in today. In addition, I would like to believe this and perhaps support this on my next blog because even today, we know for a fact that certain plants grow only at certain environments and conditions such as the “Blue Gum” that only grow in rain forests. Carrying on, as plants grew very large and was abundant during the dinosaur era, herbivores (plant eaters) ate as much of the resources that they were given and grew bigger. In addition, as herbivores grew bigger, it benefited the carnivores as there was plenty to eat for the carnivores. It was a matter of rich supply within the food chain supporting the growth and development of these species.
Scientific studies indicate that climate and the environment surrounding the species are leading factors that determine the size of species. As I said before, this is a very controversial topic that includes various perspectives on climate change and size evolution. As a matter of fact, some theories indicate that global warming will and is causing species to become smaller as time passes by while others state otherwise in the case of the Titanoboa cerrejonensis which is opposite as it states that as temperature is on the rise, cold-blooded creatures increase in size. For further information and inquiries on the general theory that supports why certain species get larger while some get smaller as temperature increases, you may want to read the link below which explains a case and validity of the Bergmann rule that states
Animals tend to become bigger as latitude increases or the climate gets colder, and animals found in warmer climates are generally smaller.
The purpose of this blog is to inform my audience that size evolution in species is also a topic that deserves more attention as global warming is on the rise. The impact of climate change will ultimately affect our food chain as size of species evolve and become larger or smaller. With uncertainty, we cannot be sure if a cat will become the prey of a mouse that becomes larger while the cat becomes smaller due to the climate change (Will probably never happen but just hypothetically). The previous statement just indicates that certain species that may have been weak in our modern world may prevail to become very dominant and powerful species in the future, threatening certain species. At worst, some species may become extinct and affect the entire food chain. We cannot predict how all of the different species will adapt to the new climate but perhaps this topic may show numerous individuals an additional reason to why we must do everything we can to stop global warming. This topic raises several questions into the future such as:
“If certain species become larger while some become smaller how will it affect the food chain? How do we preserve the lives of certain species that may become close to extinction?” ….or is climate change and size evolution just a total nonsense to you??? I am looking forward to many of your opinions.