Multicellular Organisms and Their Nervous Systems (Enhanced DVD)
How does complex life evolve from simple single cell organisms to multicellular organisms of both invertebrates and vertebrates? This enhanced DVD shows what is necessary to create a multicellular creature. All cells of any creature contain the same DNA, but in multicellular organisms, the need exists for different types of cells to perform unique functions. For example, this need for differentiation creates nerve cells, muscle cells, brain cells, and blood cells. The same type of cells group together to form a specific type of tissue. The tissues create organs. The organs support the complex needs for the life of a larger creature.
The process is fascinating. In multicellular organisms, nerve tissues are vital to keeping all the organs working properly and everything organized. In vertebrates, there is the central nervous system, which is connected directly to all other parts of the body by the peripheral nervous system. For invertebrates, the nervous system is more simply constructed such as that for the earthworm where the neurons are grouped into ganglia and all are connected by a central nervous cord.
This documentary video shows the dissection of a cane toad and an earthworm to teach the differences between the nervous systems of invertebrates when compared to vertebrates. This is a clear way to understand the complexities of the nervous systems of multicellular organisms. It shows why vertebrates differ from invertebrates in how the nervous system is organized. Vertebrates and invertebrates took different fundamental pathways in the evolution of the nervous system in order to solve the similar problems of self-organization and have a feedback response system to monitor the bodily functions.