CBSE Class 11-science Answered

We use special methods of phylogenetic inference, developed over the last several decades, to compare features present in a given group of species to allow us to figure out how they are related to one another. These methods are based on the same simple principle that closely related individuals tend to share a larger number of similar features than do distantly related individuals, as a result of their shared common ancestry.

The following classification history will help us to decide the evolutionary relationship between humans, chimpanzees, cats, tigers, rabbits, mouse, crocodile and lizards.

From the above classification system, following inferences can be made:

• All the stated organisms are chordates.
• Humans, chimpanzees, cats, tigers, rabbits and mice are more closely related to each other. Crocodile and lizards are more closely related to each other.
• Humans and chimpanzees are more closely related since they belong to the same order, Primates and same family, Hominidae.
• Cats and tigers are more closely related to each other since they belong to the same order, Carnivora and same family, Felidae.

More concrete and detailed inferences can be made by constructing a cladogram reflecting the evolutionary characters of these organisms.

Scientists can compare the DNA of two organisms to compare the evolutionary relationship between the organisms. The more similar the DNA, the more closely related the organisms.