Final answer:
Humans are classified in biology from the broadest to the most specific using the taxonomic levels: Kingdom, Phylum, Class, and Order, further based on characteristics like symmetry, germ layers, coelom, and embryological development. A phylogenetic tree reflects the evolutionary relationships in this hierarchy.
Step-by-step explanation:
Classification of Humans in Biology
In biology, the term classification refers to organizing living organisms into categories based on shared characteristics and evolutionary history, which is important in understanding the relationships between species. Humans are further classified from the most general to the most specific levels. We belong to the Kingdom Animalia because we are multicellular and heterotrophic. Within this kingdom, we are part of the Phylum Chordata because we possess a spinal cord. Moving further, humans belong to the Class Mammalia as we have hair and mammary glands. As highly developed mammals, we are in the Order Primates. This classification is based on various aspects like symmetry, germ layers, coelom, and embryological development, which are used to categorize organisms effectively and systematically.
At each level of classification, from the broadest to the most specific, organisms are grouped together based on more detailed criteria. Symmetry refers to the balanced distribution of duplicate body parts or shapes. The germ layers represent the early layers formed during embryonic development which will develop into all organs and tissues. The coelom is a fluid-filled body cavity found between the intestinal canal and the body wall in most multicellular animals, and it is important in the development of the internal organs. Embryological development further displays the complexity and specialization of species as they evolve from a single cell into a full organism.
The purpose of these criteria in classification is to reflect the evolutionary relationships between organisms, which is depicted using a phylogenetic tree. This is a diagram that shows lines of descent among organisms, representing the phylogeny, or the evolutionary history and relationships of species.