Question

Use the animal phyla to explain the evolutionary development of tissues. Include which phyla they first appeared in. Include what structures/organ systems those tissues become. Include the advantages organisms have with each tissue (what does that tissue allow).

Answer 1

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Trends in Animal Evolution | Sponges: The Phylum Porifera ... animal fossils and burrows (presumably made by multicellular animals) first appear 700 million . Sac-like body plan animals do not have tissue specialization or development of organs.

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As larvae, sponges are able to swim, but as adults, they are sessile, spending their life attached to a substrate.

• Although the majority of sponges live in marine habitats, one family, the Spongillidae, is found in fresh water.
• Calcarea, Hexactinellida, Demospongiae, and Homoscleromorpha make up the four classes of sponges; each type is classified based on the presence or composition of its spicules or spongin.
• Most sponges reproduce sexually; however, some can reproduce through budding and the regeneration of fragments.
• The majority of sponges are filter-feeders, but a few species are carnivorous due to the nutrient -poor environment in which they are found.
• parazoan: include only one phylum known as the sponges
• endosymbiont: an organism that lives within the body or cells of another organism
• spongin: a horny, sulfur-containing protein related to keratin that forms the skeletal structure of certain classes of sponge
• spicule: a sharp, needle-like piece
• holdfast: a root-like structure that anchors aquatic sessile organisms, such as seaweed, other sessile algae, stalked crinoids, benthic cnidarians, and sponges, to the substrate

---Ans: Sponges are important in nutrient cycles in coral reef systems. ... This process would lower excess nitrogen levels in coral reefs, also preventing harmful ecosystem changes. Scientists believe that the conversion of nitrogen gas into useful nitrogen is also beneficial to the survival of other organisms in the area.

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