Primary Succession Gradual growth of organisms in an area that was previously bare, such as rock. (For example lichens, mosses, and ferns will first appear on bare rock). The Following Steps: Secondary Succesion It is the series of community changes which take place on a previously colonized, but disturbed or damaged habitat, (examples include areas which have been cleared of existing vegetaion such as a tree-felling in a woodland). Primary succession occurs following an opening of a pristine habitat, for example, a lava flow, an area left from retreated glacier, or abandoned strip mine.
In contrast, secondary succession is a response to a disturbance, for example, forest fire, tsunami, flood, or an abandoned field. Compare && Contrast Primary Succession starts at bare rock. Secondary Succession starts with soil and dirt already there. Secondary Succession takes 100 +(plus) years to develop. Primary Succession takes thousands of years to develop.
Answer:
In evolutionary biology, abiogenesis, or informally the origin of life (OoL), is the natural process ... For the oldest life forms, see Earliest known life forms. ... There are several principles and hypotheses for how abiogenesis could have occurred. ... In 2017 scientists found possible evidence of early life on land in 3.48 Gyo
Explanation:
Many scientists favor the RNA world hypothesis, in which RNA, not DNA, was the first genetic molecule of life on Earth. Other ideas include the pre-RNA world hypothesis and the metabolism-first hypothesis. Organic compounds could have been delivered to early Earth by meteorites and other celestial objects. We can only speculate about these questions, since we haven't yet found any life forms that hail from off of Earth. But we can think in a more informed way about whether life might exist on other ... When did life appear on Earth? ... For many millions of years, early Earth was pummeled by asteroids and other celestial objects.
