About a number of facts and observations that show how evolution works
The Galapagos Islands served as Darwin's inspiration for the idea of evolution. Because of the great biological diversity of species in a small number of genera, when the representative type was the spreaders: because of different conditions on each island, the spreaders developed into many species that were adapted to the unique environment. The differences between the different species can be distinguished even by someone who is not an "expert" and when you check the habitats and the environmental conditions present how on each island abilities have been developed that will allow the settlers to continue to exist, abilities that are expressed in different morphological features, features that caused the formation of new species.
Recently, researchers have seen evolution in the making: researchers Peter and Rosemary Grant (GrantI) published in the journal Science the findings of their research on a small island called Daphne Major, on the island the spread 'P' existed mainly from the seeds of a prickly bush. The seeds, which were relatively large, provided a reasonable existence for the owners of the larger source, in recent years a species known as 'M' invaded the island and these competed for the food sources. A bigger source gave retiree 'M' an advantage. Sometimes hatchlings with a smaller beak "accidentally" hatch (in nests spread 'P'). Under the conditions that existed until the arrival of Parosh 'M', such chicks were in an inferior position and the chances of their existence were few, but because of the competition from Parosh 'M', chicks with small beaks managed to reach small seeds (seeds that were not reached by those with large beaks). This success gave them an advantage, an advantage that resulted in the proliferation of small-beaked Prosh 'P' and thus for a short time (ten years) Prosh 'P' developed morphological (form) characteristics that may one day constitute a new species.
Much has been written about global warming and its effect on the flora and fauna. It is accepted by biologists that the cause of the beginning: the sparking of leaves, the blooming of flowers, the beginning of nesting, the migration of birds and even
Entering winter, for all of these the main marker is the length of the day (photoperiod). That is, the biological world adjusts its clock according to the length of the day. Where until not long ago the length of the day was parallel to the rise in temperatures and thus those who directed their flowering, awakening, the beginning of their migration, throughout the day would be rewarded with temperatures suitable for activity.
Because of global warming, "the creators got confused" and the correspondence between the length of the day and the warming is not what it used to be. The first to respond to the change are annual plants and insects. These breed in large numbers, and their generations are short. That is, in each generation there are many offspring, when the biological clock is "advanced" in a number of offspring, it is a malfunction, a malfunction that under normal conditions would have caused their extinction, but when it is warmer, the malfunction is an advantage because the plants that have benefited from improved conditions and the insects that have hatched benefit from an abundance of food without competition And so annual plants and insects will be the first to benefit, the first to adapt to the new conditions.
The situation will be different for species that multiply slowly. The smaller the number of offspring in each generation, the longer the generations, the more time it will take for the species to adapt to changes. One of the countries where it is convenient to measure the effect of warming is England. Because it is a relatively isolated island, it is possible to measure the changes that apply in the biological diversity and behavior of different species. Indeed, a survey conducted to test the effect of warming on migratory birds that roost/incubate in the British Isles showed surprising results. The initial assumption was that the longer the migration route, the longer the adaptation. To the delight of the reviewers, it turned out that the assumption was inaccurate. It seems that the need to coordinate arrival at the nesting areas with an abundance of food/insects constitutes a stronger (evolutionary) pressure than the need to listen to the biological clock. The reason may lie in the fact that the warming is global, which means that the bird's breeding areas are also warming and this warming is a factor that affects the biological clock and pushes the birds to leave their breeding areas early?
From an evolutionary point of view, again, it is possible that young people / chicks whose "clocks are not set properly" return early, they of course have an advantage, and therefore will produce more offspring (whose clocks are ahead) and these will form the next generation, and thus an apparent malfunction allows adaptation to changing conditions. The survey showed that "far-migrating" birds arrive at nesting areas (in Europe) about ten days earlier than was previously known.
Of course, relative to annual plants and insects, the natural reproduction of birds is very slow, therefore together with the fact that birds arrive earlier, there is a sharp and alarming decrease in the numbers of birds. My colleague and friend Dr. Yosef Reuven, who is in charge of the nesting station in Eilat, closed the station two weeks earlier than usual, due to a very low number of birds that were "captured". It is clear that the evolution of the birds cannot keep up with the changes and therefore there are fewer birds, but we can hope that one of the reasons for the low number is the fact that birds begin their migration earlier than usual, that is, before the station's activity begins?
One way or another because of the rapid changes in environmental conditions we are given the rare opportunity to see the wondrous ways of evolution!
Dr. Assaf Rosenthal
Tour guide/leader in Africa and South America
0505640309 / 077-6172298 for details Tel.
Email assaf@eilatcity.co.il
