The first animal phylum to evolve three germ layers was the Cnidaria. These germ layers are the ectoderm, endoderm, and mesoderm, found in more complex animals for the development of different structures and organs.
The phylum Cnidaria has two layers of tissue: the outer epidermis and the inner gastrodermis separated by a jelly-like mesoglea layer. This simple body plan is characteristic of organisms like jellyfish and sea anemones.
Yes, platyhelminthes are diploblastic, meaning they have two primary germ layers during embryonic development: the ectoderm and endoderm. They lack a mesoderm layer.
Leeches belong to the phylum Annelida, which is characterized by segmented bodies, a lack of internal or external skeleton, and bilateral symmetry. Leeches also have a closed circulatory system, a well-developed nervous system, and a body covered in a layer of cuticle.
Phylum Aschelminthes
Gastrulation is first step towards germ layer development .
The tongue is derived from the ectoderm germ layer during early embryonic development.
The first animal phylum to evolve three germ layers was the Cnidaria. These germ layers are the ectoderm, endoderm, and mesoderm, found in more complex animals for the development of different structures and organs.
The phylum that has three germ layers is the Chordata phylum. This phylum includes animals with bilateral symmetry and a notochord, which gives rise to the three germ layers (ectoderm, mesoderm, and endoderm) during embryonic development. Examples of Chordata include vertebrates like mammals, birds, reptiles, amphibians, and fish.
Melanocytes are derived from the neural crest, which is a transient embryonic structure that forms from the ectoderm germ layer.
endoderm
Ectoderm
Phylum arthropoda does fall under the Protostomia clade characterized by bilateral symmetry and three germ layers.
If your question is 'Is the trophoblast present during germ layer formation (i.e. gastrulation) ?' then the answer is YES
The primary germ layer that forms the brain and spinal cord is called the ectoderm.
Nervous tissue is derived from the ectoderm germ layer during embryonic development.
The three primary germ layers in the gastrula are the ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer). Each layer gives rise to different tissues and organs in the developing embryo.