In 1921, Sanger founded the American Birth Control League, which later became the Planned Parenthood Federation of America. In New York City, she organized the first birth control clinic staffed by all-female doctors, as well as a clinic in Harlem with an entirely African-American staff.
Cephalization is considered an evolutionary trend, whereby nervous tissue, over many generations, becomes concentrated toward one end of an organism. This process eventually produces a head region with sensory organs.Cephalization is intrinsically connected with a change in symmetry.It accompanied the move to bilateral symmetry made in flatworms, with ocelli and pinnae placed in the head region.his process eventually produces a head region with sensory organs. Cephalization is intrinsically connected with a change in symmetry. It accompanied the move to bilateral symmetry made in flatworms, with ocelli and pinnae placed in the head region.
Platyhelminthes. Members of the phylum Platyhelminthes are flatworms, such as the planarian. Grubs and tapeworms are other examples of flatworms. Flatworms display bilateral symmetry; that is, the left and right halves of the body are mirror images of one another.Another characteristic of the platyhelminthes is cephalization.Cephalization means that one end of the animal functions as a head.The âheadâ contains a mass of nerve cells that acts as a brain and specialized regions for sensing light, chemicals, and pressure.nother characteristic of the platyhelminthes is cephalization.Cephalization means that one end of the animal functions as a head. The âheadâ contains a mass of nerve cells that acts as a brain and specialized regions for sensing light, chemicals, and pressure.