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Phyla Nematoda. By: Alex Palasz , Alex Roszczyk , Danielle Perri , Vicky Moskal. Germ Layers. 3 germ layers: endoderm, mesoderm, and ectoderm. Nematodes are considered triploblasts because they have three germ layers. . Symmetry. Bilateral symmetry. Coelom.
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Phyla Nematoda By: Alex Palasz, Alex Roszczyk, Danielle Perri, Vicky Moskal
Germ Layers • 3 germ layers: endoderm, mesoderm, and ectoderm. • Nematodes are considered triploblasts because they have three germ layers.
Symmetry • Bilateral symmetry
Coelom • Nematodes have a pseudocoelom because they have a body cavitiy that is lined with mesoderm and endoderm as opposed to just mesoderm.
Digestive Tract • Tube-like digestive tract with a mouth and an anus.
Cephalization • Centralization of nerves in the head region. • Nematodes have a rear nerve ring around the area of the pharynx.
Segmentation • Non-segmented.
Skeleton & appendages • The hydro-skeleton maintains high water pressure in the nematode to keep its structure. • They have a tough elastic outer-cuticle that is used for movement. • The flexibility of the muscles combined with the hydro-skeleton allows the nematode to swim in a “whip-like” movement.
Circulatory system • None • The outer-cuticle of the nematode allows nutrients and necessary materials to flow into the nematode and through its body through diffusion.
Respiratory system • None • The outer cuticle is permeable to water and gasses so it is used to breathe and absorb necessary nutrients.
reproduction • Nematodes reproduce sexually. • They reproduce through internal fertilization. In most species of nematodes, organisms are separated by sexes and the females tend to be larger.
habitat • Nematodes usually inhabit water, soil, and bodies of other plants or animals. • As many as 1 million nematodes inhabit one square yard of soil.