Final answer:
Aristotle classified animals based on whether they had blood, as well as categorizing 'dualizers' with mixed characteristics. His foundational work influenced future classification systems, including the Linnaean system. Modern classification now also considers anatomy, development, and genetics.
Step-by-step explanation:
Aristotle classified animals on the basis of their blood, distinguishing blooded animals such as humans, mammals, birds, and fish from ‘non-blooded’ animals, like shelled animals, insects, and soft-skinned sea animals. Additionally, he categorized dualizers: animals with mixed characteristics, such as whales and bats. Aristotle's work laid the foundations for future classification systems, including the Linnaean system of classification, which categorized life into kingdoms and further divisions based on a binomial system of genus and species.
While Aristotle's methodology was groundbreaking for its time, modern classification criteria involve an animal's body morphology, developmental pathways, and genetic makeup. These criteria align more closely with an evolutionary perspective, noting common traits among animals and distinguishing features that set apart different groups. Aristotle indeed set the stage for centuries of scientific inquiry into the natural world, inspiring others like Carl Linnaeus to develop classification systems that strive to reflect the underlying natural organization of the diversity of life.