<p> This pathway is found in all animals, including those that do not have antibodies i.e. animals lower in order than cartilaginous fish. It was discovered after the classical pathway and was thus called the 'alternative pathway'. | <p> This pathway is found in all animals, including those that do not have antibodies i.e. animals lower in order than cartilaginous fish. It was discovered after the classical pathway and was thus called the 'alternative pathway'. |