What a Strange Idea that tumours could become mothers!
I have mentioned in a previous blog that it was possible to create mosaic specimens from the fusion of embryonic cells of different donors at an early stage of development. Such mosaic animals are often also called “chimaeras” (after the Greek mythological beast that combined features of lion, goat, and dragon) and they can be extremely useful “tools” for the genetic researcher. —>—>
The Turtle is a Gold medal diver
With a bit of exercise and healthy lungs, anybody can do what I could do even a few years ago: holding my breath and staying underwater for 2-3 minutes. The lazy South American sloth isn’t a good diver, but should the branch it clings on break off and the animal finds itself under-water, it can indeed hold its breath for 10-15 minutes; it’s simply quite a tough animal. But there is, of course, a limit to the duration anyone can stop breathing and ducks, for instance, can do much better than the average human. They, and other diving vertebrates as well, slow down their heart beats during the under-water period, which allows them to remain without oxygen longer in the submersed condition than in air with a normal heart beat. But while a duck’s dive would rarely exceed 10 minutes, that of the emperor penguin can last for 20 minutes and may take the bird to depths of around 200 m. —>—>
The fittest survive, but what does that mean?
Even now there are still people who do not fully understand the tenet of the survival of the fittest and believe it has something to do with winners and losers of a combat and physical strength. However, that even the smallest individual could be the fittest individual perhaps under conditions of a food shortage or an availability of shelters best suitable for small individuals and that an individual which is weak, but smarter than others could become the “fittest” through the process of selection is something that needs to be emphasized. To explain natural selection, zoologists often use the example of the white and dark specimens of the peppered moth Biston betularia in England: the originally rather rare dark variety became increasingly more common as industrial pollution increased and the whitish tree trunks of birch trees turned grey with soot. When pollution levels subsided and the environment became cleaner again, it was the lighter coloured variety that gained the upper hand once more.