We all hear occasionally about one species or another that is about to go extinct. Some people might dismiss it on the spot as non-important, while others may not fully comprehend what it actually entails.
The term species is a tricky one to begin with. Currently, there are several different definitions, none of which is over-encompassing or overly consensual. One definition (the older and more traditional one) follows distinctness in morphology (e.g. different color, different size, different shape) in order to differentiate between different species. Yet another (widely used but under much debate in recent years) is the 'reproductive isolation'. This entails that if two individuals cannot reproduce and bring a viable reproductive offspring then they belong to different species. Issues with this definition are also occurring due to the fact that it does not include species with asexual reproduction (e.g. prokaryotes), and the appearance of different species that can reproduce and bring viable offspring although clearly belonging to different species (e.g. lions and tigers).
Recent decades have seen a major change in the approach to species' definition and taxonomy. The field of phylogeny following the advances in DNA technologies brought new definitions for species based on their genome and molecular markers. Defining species according to their DNA however is also proving to be an extremely subjective issue. It can vary significantly in accordance to what level of DNA distinctness we are to define as demarcating between two different species. What is more, there is that problem with prokaryotes' DNA conjugation where one individual is transferring an entire bulk of DNA to another individual regardless of their type/species. These are just a few of the problems/issues with regards to speciation and species definition (the scope of which is too big to be fully covered in this blog). For more information it is probably best to take any online (or on-site) course on evolution and taxonomy and dive deep into this amazing subject.
So, as we can see, defining a species is not as straightforward as one might think. Does that mean that we should abandon the species concept all together and the term extinction along with it? Personally, I do not think that this is a smart move. Another approach towards placing the right importance on species and taxonomy could go in terms of species uniqueness and adaptation to its environment. What do I mean by that? Let us pull back to our species of interest, the Arabian leopard. Keeping in mind that saving a species from extinction is a costly and extremely difficult task, let us exam the case at hand. Morphologically speaking, the Arabian leopard is paler and smaller than any other sub-species of leopard which makes it unique in that sense. But is that sufficient for us to want to save it and direct all the needed resources towards that end? Genetically speaking, the Arabian leopard is very similar to other leopard subspecies and can produce viable offspring with individuals of other subspecies. So, does that make it a non-unique item that is redundant and thus not worth the investment of resources and time?
To tackle this question one could bring another factor to the equation - the actual function and location of the species. The Arabian leopard diverged from the other subspecies of leopards many generations ago. Along that time, it became a specialized predator that is uniquely adopted to its harsh habitat in the arid deserts of the Arabian peninsula, Israel, Sinai, and Jordan. Living in such a harsh environment demands adaptations that other subspecies of leopards do not posses. Practically speaking, that means that if we take two leopards from Africa or Iran and release them in the deserts of Israel, they will not survive as they are not adjusted to such an environment. Moreover, specialized predators such as the Arabian leopards learn how to hunt in unique ways that are determined by their environment. To learn how to hunt on the steep cliffy terrain of the deserts in Israel is something that is best done by learning from the mother in the terrain and along a relatively long period of time. That is why leopard cubs remain with their mothers for a few years before splitting to their own fate. Accordingly, we have a two-fold problem with regards to extinction of specialized species and the Arabian leopard amongst them.
"The Arabian leopard diverged from the other subspecies of leopards many generations ago. Along that time, it became a specialized predator that is uniguely adopted to its harsh habitat in the arid deserts of the Arabian peninsula, Israel, Sinai, and Jordan."
We have many reasons to believe that if the population of Arabian leopards will go extinct in Israel (and worldwide), no substitution will ever be able to fill its space in the ecosystem. In the absence of such an apex predator that fulfills the niche of hunting on the cliffy terrains of these deserts, the rest of that ecosystem will be impacted in ways that we do not yet fully understand. There are examples of ecosystems in which the removal of a predator had tremendous impacts on the entire environment (such as the wolfs in Yellowstone that once reintroduced made us start to understand how great the impact is they have on their entire ecosystem (please check out this short clip below, where this is beautifully shown).
"We have many reasons to believe that if the population of Arabian leopards will go extinct in Israel (and worldwide), no substitution will ever be able to fill its space in the ecosystem."
If nothing else, this by itself is a reason to fight as hard as we can and devote whatever needed resources for saving species (including the Arabian leopard) from extinction. If we don't fight for them, there will never be leopards again in the deserts of Israel and the Arabian peninsula - and their absence will bring about changes (potentially drastic ones) that we are currently only able to speculate. This is why we want to save the Arabian leopards and this is why we truly believe that you too should want to save this magnificent animal.
Jonathan
Comments