Origin and Evolution of Life
Points to Remember
· Lamarck proposed that the acquired characters are passed on to the offsprings in the next generation
· Internal vital force, environment and new needs, use and disuse theory and inheritance of acquired characters are the main principles of Lamarckism.
· Overproduction, struggle for existence, variations, survival of the fittest or Natural
· selection and origin of species are the main postulates of Darwinism.
· Each species tends to produce large number of offsprings, but only the fittest can survive.
· Homologous, analogous organs and
· embryological evidences explain evolutionary relationships.
· Some traits in organisms would be similar because they are inherited from a common ancestor.
· Fossils are evidences of ancient life forms or ancient habitats which have been preserved by natural processes.
· Ethnobotanical importance of various types of plants are know through traditional knowledge.
· Astrobiology/exobiology is the science which looks for the presence of extra terrestrial life in the universe