Life forms on Earth have evolved, which is the subject of evolutionary biology. However, what is evolution exactly? It is necessary to understand the context of the origin of life, as well as the evolution of the planet, of stars, and even of the universe, to understand the evolution of flora and fauna on earth over the millennia. This is just the beginning. DoubtConnect will make things easier for you.
Why does evolution make sense?
There is plenty of evidence suggesting that evolution has taken place on Earth. Rocks contain fossilized remains of hard parts of animals and plants. The arrangement of sediments on the surface of the earth throughout Earth’s long history is visible in a cross-section of its crust. In sedimentary rocks from different ages, fossils of different life forms have been preserved that likely died during sedimentation.
As well as based on the observation of certain characteristics that are common to all vertebrates at the embryonic stage, Ernst Heckel proposed the theory of evolution based on embryological evidence. A comparative study of embryological development stages in a variety of vertebrates provides embryological evidence. During the early stages of embryonic development, the embryos of different vertebrates resemble each other and this similarity gradually diminishes as the embryo develops.
There are two types Of Evolution-
- Divergent Evolution
- Convergent Evolution
Compared with organisms of the past, the anatomy and morphology of today’s organisms clearly show similarities and differences. The similarities among these families can be used as evidence that they share ancestors. Mammals (such as whales, bats, cheetahs, and humans) have a similar pattern of forelimb bones. Despite the various functions of these forelimbs, they all share a similar anatomical structure — they all possess humerus, radius, ulna, carpals, metacarpals, and phalanges. These animals developed similar structures in different directions due to adaptation to different environments. This is divergent evolution and the structures are homologous. Ancestry indicates homology.
Both Bougainvillea and Cucurbita have thorns and tendrils that represent homology. A homologous system is derived from divergent evolution, whereas an analogous system is derived from the exact opposite. Butterfly wings and bird wings resemble one another. Although they perform similar functions, their anatomical structures are different. An analogous structure is a product of convergent evolution — multiple structures evolving to accomplish the same function.
Adaptive radiation- what is it?
An adaptation to specialized modes of living occurs when a group of animals or plants evolves into a variety of types. In closely related groups that have evolved rather rapidly, adaptation radiations are often exemplified. The Galapagos finches, which Darwin discovered there, are a good example of adaptive radiation.
Birds of different kinds were observed on the islands, all of which form seed-eating species that accidentally landed there. Therefore, different beak shapes developed as a result of the varied feeding habits of birds. In a changing environment, birds with varying food availability developed unique eating habits that enabled them to survive.
- HACKS AND TRICKS
Developing a topic through tricks and hacks makes it more interesting; however, for full comprehension, you need a book that gives easy explanations and colorful diagrams to make it easier for you to grasp. These books are a wise choice for that purpose!!
Remember: You must finish your NCERT book chapter first, the most valuable book anyone has ever written for school students, both for the basics and for the NEET exam.
- CBSE Biology Chapter-wise Solved Papers class 12th by Arihant Expert.
- Together with Biology by S.Chand Biology by Campbell and Reece.
- S.Chand’s Biology for class XII by B.P. Pandey.
- Pradeep’s A Text Book of Biology class 12 by P.S. Dhami.
Nevertheless, you must go through the tricks weekly for a lifetime of remembering, never forget to note important points and always highlight them for better results.
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