Cetaceans Flashcards
What are the sister taxa to cetaceans?
Hippopotamids.
How did marine mammals evolve?
Archaeocetes invaded the water and evolved.
What are the three main suborders of cetaceans?
Archaeoceti.
Mysticeti.
Odontoceti.
How did mammals adapt to living in the water?
Blubber and hair used to increase volume. Lipids influence thermal conductance and hair increases density. e.g. fur seals and polar bears trap air (in seals) and water (in bears) under fur as insulation.
What are the three types of countercurrent heat exchangers?
Flat plexus.
Vascular bundle.
Periarterial venous rate.
Where do baleen whales have CCHE’s?
In mouth to prevent heat loss when gulping water.
How do marine mammals deal with increases in core temp?
Dump blood where transported heat can be dissipated (flippers and fins).
What are the three types of marine mammal divers?
Shallow divers e.g. otters.
Intermediate divers e.g. bottlenose dolphins.
Deep divers e.g. weddell seal.
What is the diving response?
Stop breathing. Bradycardia. Peripheral vasoconstriction. Reduced aerobic metabolism. Oxygen depletion. Increased carbon dioxide. Increased lactic acid.
What are the advantages of diving with empty lungs?
Buoyancy control and reduced gas exchange.
What are the two stages of dives?
Aerobic stage and anaerobic stage.
What are marine mammalian respiratory systems like?
Flexible rib cage.
Rigid structure further down respiratory tract.
- Non-gas exchanging tissue, no N absorbed.
- Avoid bends.
What are anaerobic conditions?
Lowers blood pH.
Decrease in haemoglobin oxygen affinity.
What are sources of water for marine mammals?
Food.
Can consume sea water.
Metabolic water.
