• Preservation of our world’s diversity depends on Taxonomy. Measures cannot be taken to protect a species until its existence is known, it is differentiated from other species, and can be referred to by an accepted name.
• Those fancy scientific names eliminate the ambiguity of classification. Take the flying lemur for example. They certainly aren’t lemurs, and they don’t fly. This is a perfect example of why we need a universal and logical manner of classifying organisms.
• Genetic based Taxonomy (modern-day) leads to information about an organism’s evolutionary history. By figuring out an organism’s phylogeny, we can learn about changes within individual populations and even what Earth’s environment was like millions of years ago.

• It is not enough for a group of organisms to merely share some characteristics; many organisms can share many different characteristics and not be considered part of the same group. For example, fish and starfish both live in the water and have gills, however they are not taxonomically the same. It is not the presence of shared characteristics, but the presence of shared derived characteristics (those that are not present in distant ancestors) that make the difference. In the previous example, the two characteristics mentioned are believed to be present in the common ancestor of both organisms, so they are not used to distinguish the two organisms taxonomically.
• Another example of this is the “hairlessness” of whales. Hair is a primitive state for all mammals (since they all have it), while the hairlessness of whales is a derived state for their group. This can be a synapomorphy for this group.

• The gray wolf we are familiar with (Canis lupus) is a eutherian (meaning “true mammal”, or one that has placenta, as opposed to a “pouch” in marsupials). Canis lupus has long canine teeth, shearing premolars and grinding molars, like those in the common domestic dog. They are currently found in the United States, Canada, Mexico, and Eurasia.
• The Tasmanian wolf (Thylacinus cynocephalus – now extinct) has many convergent characteristics to the gray wolf—overall body shape, the aforementioned teeth structure, padded feet, and most likely diet. However, the Tasmanian wolf is a metatherian (meaning it is a marsupial—it has a pouch), and was found only on the southwestern side of the island of Tasmania (off the coast of Australia).
• What does it all mean! Well, when looking at this information, it may appear that the Tasmanian wolf is a type of gray wolf, or vise versa. However, if you look more closely at this information, you can see that this resemblance is solely on the surface, and does NOT reflect evolutionary relationships. They only look alike because they have adapted to the same environment. The presence of the pouch inside the Tasmanian wolf is proof enough that it is in no way a “true” mammal like the gray wolf.
• Look on page 3 of Lab 11 in your lab manual for another good example of this concept. It is very important to understand, especially if you plan on taking more biology classes and learning more about taxonomy or cladistics.

• The character state “hair present” is shared by both species A and B, but not by C. This represents a shared derived character (a synapomorphy) for species A and B.
• The character state “specialized teeth” is shared by all of the species shown. Therefore, it is a primitive character, and is NOT a shared derived character.
• The character state “wings” evolved independently in species A and species C. This represents a convergent characteristic.
• The stars represent the most recent common ancestor. The points show when species A and B diverged from C, and when B diverged from A.

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