1. Adaptations of the Platypus adam Ohl

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

3. 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

4. Steropodon
Cretaceous period 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.

5. Present day Platypus

6. 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

7. 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.

8. 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.

9. 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?

10. 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?

11. 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.

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

13. 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.

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