List the five major events during geological time period beginning from origin of life. You may begin with origin of animals
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Answer:
I am beginning from origin of life forms in earth. If you want to take after that then start from the 2nd event.
1st Event: 3.5 Billion years ago: First unicellular life evolved in the form of photosynthetic bacteria which produced oxygen in the atmosphere.
2nd Event: 500 Million years ago: Evolution of fish like vertebrates occurred in the water bodies.
3rd Event: 450 Million years ago: First living organism moved into land from water. They were arthropods which further evolved to form species like spider, scorpions, etc.
4th Event: 420 Million years ago: First phototropic life on lands evolved in the form of plants.
5th Event: 360 Million years ago: The four-limbed vertebrate life forms moved into land from water.
6th Event: 225 Million years ago: The evolution of species of dinosaur and mammals took place.