Body
All creatures in Phylum Annelida are segmented worms. With bilateral symmetry, these worms are made up of small segments shaped like rings. Inside they have a remarkably incredible body cavity. Their circulatory system can transport nutrients and gases easily. Their digestive system is also very interesting. The worms gut travels all the way through the body. Separated into segments corresponding with the outer segments, the gut is filled with a fluid which give the worm its tube shape. Just like our system, the worm gut is lined with muscle to help move thing along. Clearly, a segmented worms body is exceedingly extraordinarily, inside and out.
Reproduction |
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Segmented worm can reproduce both asexually and sexually. They reproduce asexually by being broken and regenerating or budding. They can reproduce sexually by releasing free swimming fertilized eggs that turn into larvae, then they gather together and form a cocoon. The final stage of sexual reproduction is the cocoon hatching and larvae that come out are no longer larvae, and look like their parents in a smaller form.
Class Polychaeta
Animals in Class Polychaeta, also known as polychaetes, are astonishing. Their habitat can vary some of the worms live and crawl around on the ocean floor, while others burrow in the mud and sand. The last habitat is when the segmented worm makes a hollow tube created from limestone and a variety of other particles. Their body depends on their habitat, if it lives on ocean floor it will look like the pictures above, but if it lives in a tube than it will look like the pictures down below.