In Australia, the hybrid Posidonia plant shows how evolution works
Whether we are talking about the few weeks in which the variables of Covid emerge or the thousands of years needed to change ecosystems, the truth is that there is no ‘natural equilibrium’
Sometimes, to get a feel of how the process goes Darwinian evolutionJust watch the emergence of new species for a few months genome In the population and the gradual replacement of the old. This is the case with variables SARS-CoV-2: Viruses with novel properties that confer some advantages, in terms of transmissibility, evasion of our immune response, etc., rapidly invade the environmental niche represented by our bodies, extinguishing previous strains within a few weeks.
Other times, however, the impression The apparent stability of ecosystems And organisms for thousands of years hide the evolutionary process, creating the illusion of A basic “natural balance” does not exist. What harm does it do to support reactionary ideologies without a scientific basis. For example, if we look at a file Shark Bay In the western tip of Australia, an idyllic place with an amazing marine ecosystem, we can imagine that the submerged prairie consists of a plant also found in the Mediterranean, Posidonia, represents a stable equilibrium point; In fact, if we could go back thousands of years, that environment would still appear in its place.
Now researchers have determined that behind this apparent stability there is in fact a Adaptation process and continuous biological invasion. in article Just published, facts worthy of a sci-fi movie have emerged: The Posidonia that can be observed in Shark Bay is actually the result ofSpontaneous crossbreeding of two species closely related, which formed Organism whose growth and expansion seem unstoppable. One hybrid plant, i.e. today, extends even further 180 square kilometersconstitutes the largest organism so far identified and beats the previous record by more than an order of magnitude mushroom. It seems that the current plant, the clone that has expanded disproportionately, has 40 chromosomes, instead of the usual 20, after the original crossbreeding; Of these, 20 belong to Posidonia australisthe other ad Another type, now unknown.
Starting with a single event in which the original hybrid was formed, which is estimated to have occurred 4500 years agoTake the new body Downwind of all ten Posidonia meadows examined in Shark BayExcept for one. Very old giant genetic hybrid – A genetically modified organismsif we are – that continues to conquer space at the expense of other species, perhaps because some acquired genetic trait is particularly useful and able to increase the fitness of its owner, perhaps because of greater Withstand high temperatures and salinitythe study authors speculate.
Now, this example shows how, at all time scales, the Darwinian process of evolution keeps ecosystems far from a state of permanent equilibrium, even when environmental conditions remain relatively constant. Whether we observe the evolution of the SARS-CoV-2 cluster occurring within a few weeks, or those of the Posidonia population in which a single individual has taken over for thousands of years, The essence of biological communities is their diversitynot only the adaptation to an optimal and constant state over time: the selective pressure is constantly changing, but also the simple occasional appearance of individuals more tolerant of a greater number of conditions or better adapting to a single highly diffuse state that results in the alternation of organisms on the Darwinian stage.
Accurate awareness of the fact that there is no recoverable state, but rather a set of change processes that occur a Continuous different rhythms, it should raise awareness of the harmful effects that human action can have on ourselves: that is, it is not damage to a non-existent “state of equilibrium”, but rather the interaction with a dynamic process, in which we blindly accelerate and change its course, without any possibility of controlling its development even Short term. As we know, perturbation of a dynamic system is much more dangerous than not bringing a stable system out of equilibrium; If a dynamic system exhibits chaotic behavior – as with the evolution of ecosystems – the risk of reaching conditions very harmful to many organisms, including our own, is extremely high. It is not the balance that we need to restore, it is a balance Evolutionary dynamics very quickly We need to stop activating.
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