Webannelid nervous system. The brain of most annelids (phylum Annelida; segmented worms, including the leeches and terrestrial earthworms) is relatively simple in structure. The earthworm brain is a bilobed mass …
Nervous system - Annelids Britannica
WebJun 8, 2024 · Only sponges (phylum Porifera) have asymmetrical body plans. Some animals start life with one type of body symmetry, but develop a different type as adults; … WebSponge. Image courtesy of Biodidac Sponges are the only multicellular animals without a nervous system. They do not have any nerve cells or sensory cells. However, touch or pressure to the outside of a sponge will cause a local contraction of its body. Hydra. The hydra has a nervous system characterized by a nerve net. A nerve net is a ... er1882 thermo
What is the definition of cephalization in biology?
WebJul 7, 2024 · Does a sponge have cephalization? Sponges have no particular symmetry; they are not radially or bilaterally symmetrical. … Cephalization only occurs in bilaterally symmetrical animals. Body cavity. The body cavity is the place where digestive and other internal organs form. WebStudy with Quizlet and memorize flashcards containing terms like Give an example of an animal with bilateral symmetry not mentioned in the text., Use the characteristics of … Cephalization is a characteristic feature of the Bilateria, a large group containing the majority of animal phyla. These have the ability to move, using muscles, and a body plan with a front end that encounters stimuli first as the animal moves forwards, and accordingly has evolved to contain many of the body's sense … See more Cephalization is an evolutionary trend in which, over many generations, the mouth, sense organs, and nerve ganglia become concentrated at the front end of an animal, producing a head region. This is associated with See more Cnidaria, such as the radially symmetrical Hydrozoa, show some degree of cephalization. The Anthomedusae have a head end with their … See more • Noogenesis • Organogenesis • Phylogenetics See more er 16 angry birds coin crash