Write short notes:
Connecting link

Explanation

i. Connecting links are some plants or animals that show morphological characters by which they can be related to two different groups of organisms.
ii. Peripatus is the connecting link between two different groups- annelida and arthropoda. It shows annelid-lide characters such as segmented body, thin cuticle and parapodia like organs. It also shows arthropod like characters such as tracheal respiration and open circulatory system.
iii. The duck billed platypus is a connecting link between mammals and reptiles. It shows similarity with mammals due to the presence fo mammary glands and hairs. It lays eggs like reptiles.
iv. Lungfishes are connecting links between fishes and amphibians. The lungfish performs respiration with lungs even though it is a fish.