Reptile evolution: reptilia and the apple

One of the most fascinating virtues of life is that, if environmental conditions permit, it is capable of continuing to generate new organisms of increasing structure and complexity. Following this maxim, the amphibians that colonized planet Earth about 360 million years ago were no exception, and their different progenies formed evolutionary branches that diversified the vertebrate fauna of Pangea. Some of those lines of primitive batrachians, 270 million years ago, would give rise to and evolve reptiles, without a doubt, one of the 5 classes of vertebrates with the greatest diversity of living forms in the great tree of life.

And the LORD our God said to the serpent: —Because you have done this, you will be cursed forever, more than all the animals, and more than all the beasts of the field; you will walk on your belly, and you will eat dust all the days of your life.Genesis 3:14.

Primal reptiles appeared during the Carboniferous period, within the Paleozoic era, with the Hylonomus as the first fossil identified, and they should have thrived in a world where large biomes were dense forests similar to rainforests. The need to become increasingly independent from the liquid element gave them evolutionary adaptations to adapt to the mainland; improvement of the cardiovascular system and pulmonary respiration, dry, impermeable and scaly skin, unique in the animal kingdom, and an oviparous reproduction that kept their embryos covered and protected by amniotic fluid. Being born out of water would now be possible.

Many forms evolved and flourished during the Mesozoic, also known as the “reptile era”, which reached its zenith in the Triassic with the absolute dominance of dinosaurs as the superior vertebrates of Planet Earth, and then there were up to 23 orders of species, of which only 5 have survived to this day. It seemed like a world made and designed for reptiles, but that meteorite transformed everything.

There are currently about 11,000 documented reptile species in the biosphere, of which 21% are in danger of extinction. The global assessment report published by the Journal Nature In April 2022, it determined that more than 1,800 species are at risk of disappearing.

Science has taken a long time to properly catalog these animals. Undoubtedly, reptiles are less charismatic than mammals or birds, and they don't have as many associations for their knowledge and conservation. It seems that the biblical anathema of Genesis had a great predicament, especially among countries that mostly professed the religions of the big book; Jews, Christians and Muslims. For centuries, reptiles, and especially snakes, starred in atrocious and monstrous mythological stories, personifying representations of the devil and embodying the greatest miseries of the human condition, negatively permeating the culture of societies and contributing to enormous ignorance, unfounded fear and indifference to their biology and threats. The good reptile was the dead reptile.

To find the main threat, you only have to look at a bipedal mammal: the human being, which causes deforestation, the expansion of urban areas, the transformation of soils to increase agricultural or livestock area, the introduced invasive species, the catches for terrarium pets, direct persecution and hunting in the case of turtles and crocodiles, have caused very serious population breaks in hundreds of species.

In the Iberian Peninsula there are about 60 species of reptiles, with 12 of them, 20%, classified as vulnerable or endangered, most notably the brown turtle, the common chameleon, the great saurus of the Canary Islands and the endemic lacertids of the Balearic Islands.

It is undeniable that the collective imagination of most human cultures, perhaps with the exception of Hindu and Buddhist creeds and the peoples of pre-Columbian America, has made reptiles in general—and snakes in particular—repulsive beings that should be eliminated. From the serpent of Eden to the basilisks of Greek mythology, to the snout that bit the Little Prince or the huge Python obsessed with engulfing Mowgli in the Jungle Book, their terrifying legends invaded stories and fables around the world. In this sense, in many rural myths of the Mediterranean basin, there was talk of the crazy ability of snakes to hypnotize mothers while they were breastfeeding, to stick their tail in the baby's mouth as a “pacifier” so that he would not cry and thus prevent him from waking up his mother and, through this convoluted skill, a good binge of human milk.

Although slowly, science has been able to eliminate these myths and demonstrate that reptiles, which are major consumers of insects, mollusks, granivorous birds, lagomorphs, thalpids and rodents, play an essential role in balancing ecosystems, sanitizing populations and eliminating pathogen carriers, becoming great allies for the control of species that feed on agricultural crops and are harmful to crops or act as potential transmitters of numerous human infections, specifically, up to 20 types of diseases in the case of rats and mice.

Reptiles are one of the most fascinating animal groups in existence. The stealth of their movements, their elusive habits, their beautiful colors, the surprising hunting techniques they use on their prey, the indomitable nature of their behavior and their very rich evolutionary phylogeny, must make us understand their importance in evolutionary history, the functioning of nature and the multiple benefits they bring to human beings and, therefore, learn to respect and conserve them.

And so, and once and for all, to ensure that that diabolical apple does not continue to be the excuse or the revenge to continue destroying this lineage of amazing living beings.

To learn more:

• Manual for the identification of reptiles and amphibians in Europe and the Iberian Peninsula. (2001). Halliday, M. O'Shea. Omega Publisher.
• Atlas and Red Book of Amphibians and Reptiles in Spain (2002) Ministry for Ecological TransitionJuan M. Pleguezuelos, Rafael Márquez Miguel Lizana (Scientific Editors)
• Amphibians and Reptiles from Spain, Canary Islands and Balearic Islands. (2011) Editorial Omega. New Field Guides. A. Masó, M. Pijoan
• Reptiles from Spain (2013). Omega Publisher. Alfredo Salvador; Juan M. Pleguezuelos.
• My first field guide for amphibians and reptiles (2017). Tundra Publisher. Víctor J. Hernández
• Guide to Amphibians and Reptiles of the Iberian Peninsula, the Balearic Islands and the Canary Islands. Ed. GeoPlanet. Barcelona. Year 1999.