Question

What organisms were dominant after the five mass extinctions?

Answer 1

After each mass extinction, new species evolved to fill ecological niches, such as the rise of mammals after the Cretaceous-Paleogene mass extinction.

Step-by-step explanation:

After each of the five mass extinctions, there was a sudden burst of new species evolving to fill the ecological niches left empty by the extinctions. For example, after the end-Permian extinction, 96% of all marine species and 70% of all terrestrial species were lost, but it allowed for the rise of new species, including mammals (our ancestors). Similarly, after the Cretaceous-Paleogene (K-Pg) mass extinction that led to the extinction of dinosaurs, mammals thrived and became dominant.

Answer 2

The last of the first five mass extinctions was at the end of the Cretaceous and almost 50 percent of the organisms living then went extinct. This is when all non-flying dinosaurs died. The major theory for this extinction was an asteroid or comet hitting the Earth. After this extinction, the dominant organisms in this new time period were mammals. In fact, many of the most common mammals that we know today originated in this period such as primates, rodents, and hoofed- herbivores like cows and deer. There were also a lot of birds in this time period including many large, flightless birds that are now extinct.