Sponges
The First Living Organisms
Level of Organization
Sponges have cellular level organization which means their cells are specialized to perform different functions.
Germ Layers
Sponges are the only animals with just one germ layer.
Symmetry
A sponge has neither radical symmetry nor asymmetrical symmetry. Sponges grow in many different shapes and sizes.
Cephalization
Sponges do not undergo cephalization because they do not have a brain.
Body Cavity
The body cavity of sponges is large, it is open to the outside world, and it allows the sponge to consume food.
Segmentation
No segmentation
Digestive System
A sponge takes in food from the water that flows through their pores. The sponge filters out the small food particles within the water.
Circulatory System
The sponge gets the food and oxygen it needs from the water flow through its pores.
Respiratory System
The sponge take water through its pores and the oxygen from the water is used.
Excretory System
The sponge removes carbon dioxide and other waste products through its pores as the water goes through.
Nervous System
Sponges have a low level of reaction to the world around them. They also do not have a brain.
Reproduction
A sponge reproduces by budding and growing new sponges.
Support
Sponges are made up of collagen which supports the shape of the sponge.