Humans (about 6.8 billion worldwide, as of June 2010), but the Common House Mouse and the Norway Rat are also very populous.
The kingdom Animalia has the greatest number of species.
mammal
Humans are a species of mammal.
Yes
The insects, of which about one million species are known. This is about half of the total number of species known.
Habitats
The family taxonomic level for a given genus typically includes the greatest number of species. Families consist of multiple genera, each with their own set of species.
rhizopods
Australia
Insects have the greatest number of different species. There are literally millions of species of beetles.
The greatest number of species extinctions took place during the Cretaceous-Paleogene extinction event. During this event, almost every species on the planet became extinct.
Actually, the rainforest supports the greatest number of species of plants and animals. The grasslands support a greater variety of species than the desert.