Marine Mammals Flashcards
Name the three main groups of marine mammals and their approximate number of species
Sirenians (4 species), Pinnipeds (36 species), and Cetaceans (87 species). These groups evolved independently.
Name two adaptations marine mammals have developed for aquatic life and explain their function
Streamlined shape reduces drag in water. (2) Increased oxygen-carrying capacity due to higher myoglobin concentration and increased blood volume allows longer dives.
Name the three families in the order Pinnipedia and their distinguishing features.
(1) Phocidae (earless seals) – lack external ears, move by undulating on land.(2) Otariidae (eared seals) – have external ears, use forelimbs for propulsion.(3) Odobenidae (walruses) – have tusks, adapted for ice habitats.
What is the countercurrent principle, and why is it important for thermoregulation in marine mammals?
A heat exchange system where warm arterial blood transfers heat to cold venous blood, minimizing heat loss in cold environments.
What are the two major groups of whales, and how do they differ in diet?
Mysticeti (baleen whales) filter-feed on small organisms using baleen plates. Odontoceti (toothed whales) hunt prey and use echolocation.
What role do baleen plates play in baleen whale feeding, and how are they structured?
Baleen plates, made of keratin, hang from the upper jaw and filter small organisms like krill and plankton from the water.
What factors led to intensified whale hunting in the 19th century, and what were the consequences?
Introduction of harpoon guns and steamships increased hunting efficiency, leading to massive overhunting and population declines.
What is the “whale pump,” and how does it influence ocean nutrient distribution?
Whales transport nutrients by feeding at the surface and excreting waste at depth, promoting phytoplankton growth.
Why do large whales have a lower mass-specific metabolic rate, and what impact does this have on ecosystems?
Their large size reduces their metabolic rate, allowing them to store more carbon. Their carcasses also contribute nutrients to deep-sea ecosystems.
What is baleen?
Keratin plates in baleen whales’ upper jaw used for filtering food from water.
What is myoglobin?
A protein that stores oxygen in muscle cells, allowing longer dives in marine mammals.
What is osmoregulation?
The ability of an organism to regulate water and salt balance in the body.
What are pinnipeds?
A group of marine mammals that includes seals, sea lions, and walruses.
