How many species concepts are there?
It's an old question in biology: what is a species? Many ... species concepts in biology are biological, and so I call them "reproductive isolation concepts". Let's call them "reprospecies" for short. So, back to Chicago: 26-27, or 7, or 2. But wait! There ...
How many dead eagles?
However, golden eagles undergo a 10-year population cycle and there is data only from four years. Also not understood is exactly how many golden eagles are in Wyoming, Sweanor said. It's difficult, especially with migratory birds, to get accurate counts ...
Just How Many Species Are There, Anyway?
from marine invertebrates to birds. "It points the way for getting the answer to how many species there are worldwide," says Rosenzweig. Society For Conservation Biology. "Just How Many Species Are There, Anyway?." ScienceDaily. ScienceDaily, 26 May 2003.
For many birds, the world's a very colourful place
but there isn't a single answer. Birds are diverse, and so the answer depends largely on the species. Birds have four types of cones in their retinas, where humans have only three types. Theoretically, than means they can see twice as many colours.
How many species are there? My latest for the New York Times
So they used this relationship to estimate how many species there are in well-studied groups like mammals and birds. They found this method got them a number close to the actual number of species. So they applied to other groups, such as plants and fungi.