Question: Biologists have several different ways to define species. 1. According to the ________ species c…

Biologists have several different ways to define species.

1. According to the ________ species concept, a species is a group
of populations whose members have the potential to interbreed in
nature and produce viable, fertile offspring. The separation
between species is maintained by ________ isolation, which prevents
gene flow between species. But in some cases, distinct species can
occasionally interbreed, producing ________ offspring.

2. Alternatively, the _________ species concept identifies species
based on physical traits or body form. This species concept can be
applied to _________ species, and it is the way most of the 1.8
million named species have been identified.

3. In the _________ species concept, species are defined by their
niche–the role they play in the environment.

4. The _________ species concept defines species as the smallest
group of individuals that share a common ancestor and form one
branch on the tree of life.