Figure 22.1 Not All Members of the Same Species Look Alike (A) It is easy to identify these two male hooded mergansers as members of the same species, even though they were photographed thousands of miles apart in British Columbia and New Mexico, respectively. Despite their geographic separation, the two individuals are morphologically very similar. (B) Hooded mergansers are sexually dimorphic, which means the female’s appearance is quite different from that of the male.