26.17. Classification of Living Beings: Phylogenetic Tree

The classification of living things is a crucial aspect of biology. Understanding the organization and interrelationship between different forms of life is fundamental to understanding biological diversity. One of the main classification methods is the phylogenetic tree.

A phylogenetic tree is a diagram that represents the evolutionary relationship between different species. It is based on the idea that all forms of life share a common ancestor and that biological diversity is the result of a long process of evolution. Therefore, the phylogenetic tree is a graphical representation of the evolutionary history of life on Earth.

In the phylogenetic tree, each branch represents a species or group of species. The position of the branches on the tree indicates the relationship between the species. Species that are closer together on the tree are more related to each other than those that are further away. The point where two branches meet, called a node, represents the most recent common ancestor of these species.

To build a phylogenetic tree, scientists use various sources of information, including the morphology of species, their behavior, their geographic distribution, and, more recently, their genomes. DNA analysis has been particularly useful in resolving phylogeny questions that were difficult to answer based on morphology alone.

There are different methods for building phylogenetic trees, but they are all based on the idea that the characteristics shared by different species are an indication of their evolutionary relationship. For example, if two species share a trait that is not found in other species, that is evidence that they have a more recent common ancestor.

A classic example of a phylogenetic tree is one that represents the relationship between different groups of vertebrates. In this tree, fish are the most primitive group, followed by amphibians, reptiles, birds and mammals. Each of these groups is represented by a branch on the tree, and the position of the branches indicates the order in which these groups evolved.

The phylogenetic tree is a powerful tool for understanding the history of life on Earth. It allows us to visualize the relationship between different species and understand how biological diversity has developed over time. However, it is important to remember that the phylogenetic tree is a simplified representation of reality. The history of life on Earth is much more complex, and there's still a lot we don't know about it.

Finally, understanding the phylogenetic tree and the classification of living beings is essential for any student who is preparing for the Enem test. These concepts are often tested on the exam, and a good understanding of them can make the difference between a good and a bad grade.

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