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.

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

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

…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

Oct 2, 2024 · 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.

May 8, 2017 · 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...

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 …

Jan 21, 2020 · 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.

Our exhibits on animals will help you make sense of the complex and beautiful story of their history. For each group of organisms (each taxon), we present information on the group's fossil record, life history, ecology, systematics and morphology.

Metazoans – heterotrophic, multicellular organisms that posses eukaryotic cells. Heterotrophs – organisms that must ingest organic carbon to support growth, unlike plants that are autotrophic and can use light to photosynthesize organic compounds.