Explanation A keystone species is an organum that that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exists altogether. Any organism, from plants to fungi, may be a keystone species;they are not always the largest or most abundant species in an ecosystem.
Genetic drift is changes in allele frequencies of a gene pool due to chance or random events. This can occur in large or small populations. Genetic drift causes gene pools of two isolated populations to become dissimilar as some alleles are lost and other are fixed.
Dinosaurs, based on recent studies show that they were larger animals and its not possible now for a bird to be the same height or weight as a dinosaur back then
