Cetacean And Pinniped Diversity And Adaptations Flashcards
What is the only air breathing vertebrate class that doesn’t have marine species?
Amphibians
What are the problems associated with returning to the sea?
Breathing
Air breathing is a waste of time and energy
What are the advantages of air over water as a respiratory medium?
Air has a low mass compared to water so it’s easier to breathe
Air has a high rate of diffusion
Oxygen is fairly constant in the air
Air has a low heat conductivity and capacity
What are the current groups of marine mammals?
Cetacea: whales, dolphins and porpoises
Pinnipedia: seals
Sirenia: dugongs and manatees
Ursidae: polar bear
Mustelidae: sea otter
What two groups make up Cetacea?
Mysticetes (baleen whales)
Odontocetes (toothed whales)
What three groups make up Pinnipedia?
Otariidae (sea lions and fur seals)
Odobenidae (walrus)
Phocidae (true seals)
What is the most recent marine mammal extinction?
The Baji and Yangtze River dolphin
What are the adaptations of Cetacea?
Increased insulation
Circulatory adjustments
Countercurrent heat exchangers
Adaptations for osmoregulation
Can dive for an extended period of time
How long can Cetacea love for?
18-100+ years
How many calves do Cetacea have at each breeding event?
One
What is the population growth percentage of dolphins and porpoises?
1-4%
How can you determine age in toothed animals?
By reading decalcified, sectioned and stained teeth
They show growth later groups (a complete GLG is one year)
How is age determined in baleen whales?
Look at growth layer groups in their ear plugs
How many species of dolphin are there?
38
In general what type of mating system do cetaceans have?
Polygynous and promiscuous mating systems
