An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. There is a sharp change in the diversity and abundance of multicellular organisms. I
Paleontologists have found evidence that after a major extinction occurs,many new species often appear at about the same time .
A biotic crisis or a mass extinction crisis is a rapid and widespread decrease in biodiversity. There is a clear change after the mass extinction, in the diversity and of multicellular organisms.
Genetic drift is referred to the changes in allele frequency in a gene pool. Gene flow is the process of alleles moving from one population to another.
