We start our look at the animal kingdoms diversity at the start of its diversity. Sponges are the simplest animals we know of, very few specialized cells, maybe tissues, but no organs or organ systems. As we move up through the ranks of invertebrates things will become more complex: body cavities will become digestive systems, nerve nets will become nervous systems, more and advanced sensory organs will develop. That is the journey, let's begin at the start.
Compare and contrast sponges, cnidarians, and worms.
Contract 7 has you choosing a unique species of simple invertebrate to present to class: the four characteristics it shares will all living things, but how your animal shows them differently, how we classify your organism and by what traits, and where your species fits in the trends of growing complexity of invertebrates.
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Look at the pretty sponge
Comparing and contrasting cnidarians, worms, and sponges
Worms, cnidarians, and sponges can all reproduce sexually which is where the sperm fertilizes the egg. Worms and cnidarians can reproduce asexually, too. Cnidarians can only reproduce sexually when they are in the medusa stage and can only reproduce asexually when they are in the polyp stage.
Every cnidarian has stingers on it for paralyzing its prey. Also every cnidarian can regenerate a body part it has lost. Worms and sponges can also respond to getting cut in half by regenerating the part lost. Sponges and polyp stage cnidarians are sessile and stay attached to a sturdy surface unlike worms and medusa stage cnidarians. Worms use the muscles on their stomachs to help them move while medusa stage cnidarians float around.
Cnidarians and sponges filter feed while worms don’t. I think between the cnidarians that float around have an advantage to getting more food because they can follow their food like the golden jelly fish follows the sunlight because the plankton are always in the sunlight. Worms feed by a little opening at the front of the body. The food goes down the body into a gizzard which grinds up all the food. Since the opening is so small all it can eat are microscopic organisms.
. They all have different circulatory systems. Worms have a closed circulatory system while cnidarians and sponges don’t have one. Sponges don’t have a distinct circulatory system because they don’t really need it because water flows through it and brings in a steady amount of oxygen and food. Cnidarians don’t need one either because all of the cells in their body are in contact with water. On the outside they are very different. Sponges are very porous and is a attached to a sturdy non-moving surface.
Erik OHman did this and I have no idea what i'm doing.
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