evolution life on earth began as simple and primitive forms, by natural selection, over a long time...
TRANSCRIPT
EVOLUTION
Life on earth began as simple and primitive
forms, by natural selection, over a long time various complex
organisms form
Evidences of Evolution
1. Paleontology
2. Geographical distribution of
organisms
3. Comparative anatomy
4. Embryology
5. Comparative bio-chemistry
PaleontologyStudy of fossil:
Differences between ancient and recent form of an organism
Development of Horse
Development of Whale
Geographical distribution of organisms
Owing to geographical isolation, organisms adapted to that isolated
habitat and become different. (adaptive radiation)
Migration between continents
Finch Beak
Galapagos tortoise
Comparative anatomyHomologous structures as pentadactyl limb have same fundamental structure but different function
Eye Evolution
Although adult structure is different, structure in embryonic stage is similar.
Embryology
Comparative bio-chemistry
Mechanism of Evolution
Lamarck’s Theory• Change in environment• Organism modify itself• More used organ enlarge• Less used degenerate• The acquired character is
inheritable
Darwin’s Theory• Change in environment• Population has inborn
different• Some good feature fit the
environment survive (natural selection)
• These reproduce and become new species
Neo-Darwinism1. Variation : Mutation and sexual reproduction
2. Natural Selection: The fittest has better chance to survive
and reproduce
3. Speciation: New species formation is caused by isolation
•Geographic isolation: physical barrier
•Ecologic isolation: different season or zone in habitat
•Reproductive isolation: different reproductive behavior
•Genetic isolation: genetic different due to isolation
Example