Friends, did you know that June 21 is World Giraffe Day? The festival is the International Union for Conservation of Nature, and on December 8, 2016, after the giraffes were listed as vulnerable animals, the Giraffe Conservation Foundation created the festival to remind everyone and encourage everyone to take action to protect the giraffes. It is said that this day is the longest day in the northern hemisphere, which complements the "length" of the giraffe.
Regarding giraffes, that's a lot of features. It is said that each giraffe looks different, they sleep standing up, and giraffes can stay longer than camels without drinking water. And today, our theme will be why is the giraffe's long neck so long?
Giraffes are considered the tallest land animals on Earth. A tall adult giraffe was once measured with a height of up to 6 meters and a neck up to 2 meters long. However, in the early days of antiquity, this tall animal was said to be the size of a fawn and was active in Europe, Asia and the African continent. However, as the planet has changed, the giraffe's range of activity has gradually shrunk to a few areas in eastern Africa. These areas are often arid and the grasslands are yellow.
The principle of "use in and out" believes that as a herbivore, in order to eat, giraffes must often extend their necks to be able to touch the leaves on the tree. Those whose necks are not long enough, because they cannot eat the young leaves of the tree, are slowly eliminated. In this way, after generations of evolution, the giraffe's neck slowly became longer, and finally became what it is now.
Genetic studies suggest that the okapi and giraffes share a common ancestor and parted ways 11.5 million years ago. Recently, an international joint study xiaozuo, using gene sequencing technology, compared the genomes of giraffes and their close relatives, Okapi, and other mammals, and found that the difference between the long neck of the giraffe and the short neck of the okapi is mainly related to the changes in the two groups of proteins. One group controls the gene expression process for body and limb development, and the other controls the expression of growth factor genes. These gene expressions are exactly the genetic mutations that giraffes carry out to adapt to their environment.
Therefore, the evolutionary view holds that the essence of evolution is not "to use it and lose it", but to change genes. Some giraffes in the giraffe population have genetic mutations, and their necks become longer, and these giraffes are more able to eat the leaves of the trees and survive when food is scarce, while the ungenerated groups are slowly eliminated due to lack of food. Over time, the "long neck" gene after the genetic mutation was retained and became the giraffe today.
That is, the giraffe's "long neck" is the result of a randomly occurring genetic mutation, not a purposeful act to eat leaves from a tree. It's just that the long-necked population is more able to adapt to the environment, so the gene of this advantage is preserved.
In general, the giraffe's long neck is the result of random genetic mutations, and the long-necked giraffe is more adaptable to survive, so the giraffe's long-neck gene continues to this day.
The mystery of the "long neck" of the giraffe is explained here, welcome friends to leave a message to pay attention, we will see you in the next issue.