Define evolution, How does it occur?
Describe, how fossils provide us with Evidences in support of evolution?
Answers
Evolution is the sequence of gradual changes from simple life forms to complex life forms, i.e., from primitive organisms that lived over millions of years ago to new organisms that exist today.
Evolution occurs by changes, improvement and modification of simple life forms. Fossils are the remains or impressions of organisms that lived in the remote past. Fossils provide the evidence that the present animal have originated from previously existing ones through the process of continuous evolution. Fossils can be used to reconstruct evolutionary history of an organism. The distribution pattern of fossils shows that the ancient fossils present in the bottom rocks are simple, while the most recent fossils found in the upper starta are more highly evolved. It means fossils form and become more and more complex as we proceed from earliest to recent rocks. It gives us an idea of time in history when different species were formed or became extinct. Thus, fossils provide us evidence in support of evolution.
⚫ Evolution is the process of change from simple life forms to complex life forms by gradual change. It is generating diversity and shaping the diversity.
⚫ It occurs over the course of time and generations by variation, speciation, natural selection, genetic drift etc. Fossils are preserved traces of living organisms.
⚫ It helps us to find the intermediate forms in between two classes etc. For example fossils of archaeopteryx helps us to know better about the intermediate form between reptiles and aves.
⚫ It tells about the extinct species through the fossil or their retained body impressions.
⚫ It helps us to know the evolutionary relationships.
⚫ This also shows the line of development from primitive to complex organisms.