Comparing the physical structure of a fish found in the arctic ocean to a similar fish found in the southern pacific ocean is one example of the science of genetics biogeography comparative anatomy taxonomy examining physical structure of organisms to determine common ancestry is the science of biogeographical analysis comparative anatomy molecular biology taxonomy the most broad category in the classification hierarchy is kingdom species genus domain two popluations of lobsters that look almost the same, but show significant genetic differences would be classified into separate species within the same genus. separate families within the same species. separate genera withing the same species. the same species. a grouping of similar species is called a habitat genus family community