26.14. Classification of Living Things: Classification of living things in phyla

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The classification of living beings into phyla is a fundamental part of biology, being essential to understand the diversity and complexity of life on Earth. Phyla are one of the main taxonomic categories used by biologists to group living things with similar characteristics. Each phylum groups together several classes, which in turn group together orders, families, genera, and species.

There are currently about 35 recognized phyla in the Animalia kingdom, the largest kingdom in terms of species diversity. Some of the best-known phyla include the Chordata (which includes humans and all other vertebrates), the Arthropoda (which includes insects, arachnids, and crustaceans), and the Mollusca (which includes molluscs such as snails, squid, and oysters).

The phylum Chordata is characterized by the presence of a dorsal chord, or notochord, at some stage of the organism's development. This phylum is divided into three subphyla: Urochordata (tunicates), Cephalochordata (amphioxus) and Vertebrata (vertebrates). Vertebrates are the most diverse and well-known group in this phylum, including fish, amphibians, reptiles, birds, and mammals.

The phylum Arthropoda is the most diverse in terms of the number of species, with over a million described species. Arthropods are characterized by having a rigid exoskeleton and joints, which allow for a wide range of movement. This phylum includes insects, arachnids, crustaceans and myriapods.

The phylum Mollusca is the second largest in terms of number of species, with about 85,000 described species. Molluscs are characterized by having a soft body, usually protected by a shell. This phylum includes gastropods (such as snails and slugs), bivalves (such as oysters and mussels), and cephalopods (such as squid and octopus).

In addition to these, there are many other lesser known, but no less important, phyla. For example, the phylum Porifera includes sponges, the first animals to evolve. The phylum Cnidaria includes corals, jellyfish and sea anemones. The phylum Echinodermata includes starfish, sea urchins and sea cucumbers. Each of these phyla contributes to the incredible diversity of life on Earth.

The classification of living things into phyla is an ever-evolving process as new species are discovered and the evolutionary relationships between species are better understood. However, despite the changes, classification into phyla remains a valuable tool for biologists to understand life on Earth.

Understanding the classification of living beings into phyla is essential for the Enem test, as it is a fundamental part of biology. Furthermore, this understanding can help you appreciate the incredible diversity of life on Earth and the importance of conserving that diversity for the future.

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