EVOLUTION #2

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• EVIDENCE FROM COMPARATIVE ANATOMY:- There is evidence of evolution in certain anatomical features of a vertebrate. There is a progressive evolutionary change in the anatomy of the heart in all categories of a vertebrate. The piece has a simple heart with one auricle and one ventricle, amphibians, two auricles and one ventricle, reptiles, two auricles and a partially divided ventricle and two ventricles. In the process of these changes, the circulation of blood also changes from a single to double circulation

• EVIDENCE FROM EMBRYOLOGY:- Embryo is the organism that develops after fertilisation of the egg before birth or hatching. It is noticed that in the embryology of vertebrate, for instance, there are stages which resemble the embryo of other are stages which resemble the embryo of other vertebrates from which they are believed to have evolved. For example, the embryo of man in the womb at different stages of development resembles embryo of fish amphibians and reptiles. This is as a result of the fact that man evolved from ancestors whose embryo were like those seen in human embryology.

• EVIDENCE FROM VESTIGIAL ORGANS:- The presence of vestigial organs also help to explain evolution. Vestigial organs are minute or incomplete organs that have no special function. In line with evolutionary theory, vestigial organs are the remaining parts of once-functioning organs e.g the caecum in herbivore. Again the rudimentary tail in human is well developed in many other mammals.