Adaptations of the Platypus adam Ohl

Question What types of adaptations has the platypus evolved what purpose do these adaptations serve? Focus on: Appendages, Venom, and Sensory Adaptations.

Lineage Monotremes- Egg laying mammals. Only found in Australia Synapsids- Mammals, and mammal like animals. Monotremes- Egg laying mammals. Only found in Australia Platypus and Echidna

Steropodon Cretaceous period 65-146 MYA Obdurodon 5-25MYA larger beak and body then platypus Little is known about platypus ancestry. Earliest known platypus fossil is about 100,000 years old.

Present day Platypus

Appendages/Swimming mechanism Four webbed feet Front feet have retractable webbing for land use Front feet are used for to paddle through water Hind feet are used for stabilization. Beaver like tail Used as a rudder Video

Feet on land Frontal feet Hind feet Very clumsy walkers Walk as reptiles with feet to the sides Frontal feet Used for digging Hind feet Used for anchoring Why did they evolve these mechanisms? Believed that as ancestors began to depend on food sources from water they less relied on land sources Proven by platypuses ability to move on land. Ancestors such as Steropodon had feet with little webbing and were probably more home on land near water then actually in the water.

Venom Only males can produce venom Venom is strong enough to kill smaller animals, and can cause sever pain and disable a person. Males spurs are grow larger in mating season. Meant for male to male competition. Spatial Segregation.

Senses Eyes and Ears an Nose Small eyes and ears and nose Eyes, ears, nose are closed when diving. If Platypuses spend the majority of their time in water or in underground nests then why do they retain these attributes at all?

Believed that ancestors who used to live on land but dive in water actually used their outward senses. Traits of eyes and ears were passed on though the uses of them were diminished If platypus does not rely on outward senses then what do they use?

The Bill!!!!! Hundreds of thousands of tiny electroreceptor's and mechanoreceptors. Located on Dorsal side of beak Detects water disturbances and electrical discharges. Possibly developed during Cretaceous- Tertiary extinction event. Roughly 65 million years ago.

Mechanoreceptors- Detect physical disturbances in the environment Electroreceptor's- detect electrical discharge from muscle contractions of other organisms.

Ideas of New research Study of genetic make up to create a defined ancestor lineage. I would like to know more about the significance of the why the platypus continues to lay eggs.

Gregory, J. , Iggo, A. , Mcintyre, A. , and Proske, U. 1988 Gregory, J., Iggo, A., Mcintyre, A., and Proske, U. 1988. Receptors in the Bill of the Platypus. Journal of Physiology 400: 349-366.   Pasitschniak-Arts, M., and L. Marinelli. 1998. Ornithorhynchus anatinus. Mammalian Species 585: 1-9. Pettigrew, J., P. Manger., and S. Fine. 1998. The sensory world of the platypus. The Royal Society 353: 1199-1210. PLATER, G., R. Martin., and P. Milburn. 1995. A Pharmacological and Biochemical Investigation of the Venom from the Platypus (ORNZTHORHYNCHUS ANATZNUS). Toxicon.33: 157-169.