The beginning of life on earth is characterized by a favorable suite of conditions. as the climate and environment changed, so did the types of organisms that developed. describe the conditions on earth that made life possible for different types of organisms. think about geologic and evolutionary time scales in terms of how long it took for different organisms to development and become successful. relate the history of life on earth to how the climate and environment is changing today, especially in terms of rate of change.

Is the explanation of life in Earth.

Explanation:

At the begging in the era called Archean, 3500 millions of years ago, the first life forms or Earth started to appear, in seas, where there were nutrients, water, heat from sun, etc. Later on 2500 millions of years ago, the first stromatolites appeared, they were so important because were the first group of cyanobacteria together, they can start to produce a little bit more oxygen in water seas. In the precambrian era (600 millions of years ago), the bacteria evolve into a complex living things like worms, jellyfish, etc. to the cambrian period, they evolve in the first vertebrate animals. by the ordovician period (489 millions of years) the first plants started to appear in Earth, turning the atmosphere greener because of the photosynthesis that they made. and at that time also,  the ocean seas started to separate the continents ( the supercontinent called Rhodinia). Later in Devonian period ( 418 millions ago) the first reptiles started to appear on earth, with this step the first animals appear to conquer the Earth. By evolution, these animals turned into different living things like birds and dinosaurs. It was until the Jurassic period (200 million of years) where the pangea split in different continents and it was the gold era of dinosaurs. Later until the Quaternary period (1.8 millions of years)  humans we started to appear.

sex cells are usually half's then they find another half and make a fertilize egg