Sponges are the most simple of all animals. Because they have no tissues, some scientist believe that they should not be categorized as their own animal, but rather a community of specialized single celled organisms working together. They still have many characteristics in common with the protist ancestor shared by all animals.
Specialized Parts in Sponges
A sponges life is entirely dependent on water. It's specialized cells all work together so that the sponge can receive optimal usage of the water it lives in
Pore (Ostium)
As the name "porifera" means "pore bearer," sponges are covered in small holes that allow water to flow into their bodies. Because the water moves into the sponge, we call them incurrent pores. Pores are also called Ostia. Osculum
Water exits the sponge out of the large opening at the top called an osculum. Filter Feeding
Sponges filter the food out of the water that goes in their pores. The "filtered" water then exits through the osculum. |
Choanocytes or Collar Cells
Choanocytes are specialized cells that use flagella, whiplike structures, to create a water current and trap the food from the moving water. Archaeocytes or Amoebocytes
Amoebocytes are specialized amoeba-like cells that can move around within the walls of the sponge. They can move and digest food, move sperm cells of other sponges to egg cells, They can move to build spicules where needed. Spicules
Harder sponged have a simple skeleton made of small spike-shaped structures called spicules. Softer sponges are made of a network of fibers called spongin. in the ostia
out the osculum |
Reproduction
All animals reproduce sexually so that they receive a set of chromosomes from two different parents, but some, like sponges can also reproduce asexually, creating an identical copy of one parent.
All animals reproduce sexually so that they receive a set of chromosomes from two different parents, but some, like sponges can also reproduce asexually, creating an identical copy of one parent.
Sexual Reproduction
An adult sponge releases sperm cells into the water
The sperm enters through the pores of another sponge and fertilized an egg cell
A larva develops and leaves through the osculum
The larva settles on a hard surface and develops into an adult sponge.
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Asexual Reproduction
Sponges can reproduce asexually by budding and fragmentation
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