Protozoans are animal-like unicellular organisms, belonging to the kingdom Protista, whereas metazoans are multicellular organisms, belonging to the kingdom Animalia.

The meaning of METAZOAN is any of a group (Metazoa) that comprises all animals having the body composed of cells differentiated into tissues and organs and usually a digestive cavity lined with specialized cells.

2019年4月4日 · The main difference between Protozoa and Metazoa is that Protozoa is a group of unicellular primitive animals known as protists whereas Metazoa is a group of multicellular animals. Furthermore, the main forms of protozoans are Amoebae, flagellates, ciliates, and Sporozoa while the two main forms of metazoans are vertebrates and invertebrates.

…origin of multicellular animals (metazoans) was long dominated by German embryologist Ernst Haeckel’s theory that the original metazoan ancestor was a spherical protozoan that was structurally similar to the cnidarians (e.g., jellyfish and corals). Currently there are two alternative explanations. The first traces metazoans back to Read More

2021年8月15日 · The significant difference between the Protozoa and Metazoa is that the Protozoans are single-celled, though the Metazoans are multicellular. Secondly, the former one (Protozoa) belongs to the primitive type while the latter (Metazoans) belongs to the developed type of animal kingdom.

2024年10月2日 · Metazoa, also known as the animal kingdom, encompasses all animals that are multicellular and possess differentiated tissues. These organisms are characterized by their complex cellular structures and specific functions, making them distinct from single-celled organisms like protozoa.

All the rest of the animal kingdom consists of Metazoans, where cellular differentiation has led to three cell layers. First the ectoderm and endoderm form. Then, in between these two layers the mesoderm secondarily forms, the cells of which become muscles and …

2017年5月8日 · Here, we review the results of these investigations and discuss their implications for understanding the earliest stages of animal evolution, including the origin of metazoan genes and genome...

2020年1月21日 · Animals (Metazoa) are a group of living organisms that includes more than one million identified species and many millions more that have yet to be named. Scientists estimate that the number of all animal species is between 3 and 30 million species.

any animal of the group Metazoa, whose bodies are multicellular, as distinct from the PROTOZOANS where the bodies are unicellular. Sponges (see PARAZOAN).are the only nonprotozoan group excluded from the Metazoa.