Exam 1 Flashcards
What is a marine mammal?
Mammal bound to marine habitat.
Viviparous
Lactation/mammary glands
Hair/fur
Define viviparous
It means “live births”
What are the Orders of Cetaceans?
Odontocetes
Mystecetes
Order Odontoceti characteristics
Toothed whales (includes dolphins) One blow-hole
Order Mysticeti
Baleen whales
Two blow-holes
Order Sirenia
Manatees and dugongs
What are the sub-order names for Manatees and dugongs?
Manatees: Trichechidae
Dugong: Dugongidae
If Pinniped is a sub-order, what is its Order name?
Carnivora
What are the families of Pinnipeds?
Phocidae
Otaaridae
Odobenidae
What are Phocides?
True Seals
What are Otaarids?
Sea lions and Fur seals
What are Odobenids?
Walrus
Other Carnivora families and what are the animals?
Mustellidae: Sea Otters
Ursidae: Bears
What was the cause of marine mammal evolution?
- Lack of terrestrial resources (No space, no food)
- Predators on land
- Swimming
- Sea Level
- More food in the aquatic environment
How many million years ago was the cretaceous/tertiary extinction? (End of the dinosaurs)
65 Mya
When did the first cetacean fossil show up? where was it found? and what was the name of the animal?
54 mya, in Pakistan, and named Pakicetus
When did the first sirenian fossil show up? and where?
50 mya in Egypt/Italy
Why were there also fossils of sirenians and cetaceans found in Jamaica and South Carolina?
They migrated because the tethys sea was closing up.
What animal arrived about 30 mya? Where? and what present day animal did they resemble?
Desmostylians showed up in the North Pacific and looked like a modern day Hippo.
What animals started to show up about 27 mya? and where?
Pinnipeds in the North Pacific
What happened major event happened about 30 mya and explain it?
The circumpolar current and polar ice caps are established from Antarctica splitting away from South America.
Cold water circulation sinks and develops deep water currents, which leads to coastal upwelling which produces an abundance of nutrients.
What showed up about 15 mya?
Bears
What showed up about 5 mya?
Aquatic Sloth
What showed up about 1-3 mya?
Modern sea otters
When did polar bears show up?
Roughly 300,000 years ago.
What are the subfamilies of the family Otariidae? and which animal are they? and where do they specifically live?
- Otaarinae: Sea Lions
- Arctocephalinae: Fur Seals
Only in the Pacific in the northern hemisphere
What is the closest outgroup of Cetaceans?
Ungulates (Cows, etc.) (Even-toed, hoofed animals)
What cetacean characteristics did Pakicetus have?
Cetacean ear
Amphibious predator but more terrestrial.
What evolved from Pakicetus? And what did they look like?
48 mya- Ambuloretus - “Crocodilian”
48 mya- Protocetidae - more aquatic - started dorsal kicking
40-34 mya- Basilosauridae - Looks like a whale but still has tiny hind legs
40-34 mya- Dorudontidae - Direct ancestor of modern odontecetes
Physical adaptations from Pakicetus to Dorudontidaes (54-34 mya)
Reduction in hind legs, pelvic girdle
Blowhole moving back (about half-way back on head)
Flexible elbow
Heterodont teeth
Differences between Mysticetes and Odontocetes
Mysticetes: Teeth, symmetrical craniums, 2 blow-holes, more floating ribs, telescoping of skulls differ.
Odontocetes: Baleen, 1 blow-hole, Asymmetrical cranium, large breastplate/ribs
Types of Cetacean distribution
Cosmopolitan
Anti-Tropical
Circumpolar
Pantropical
Pachyostotic bones
Solid bone throughout the manatee body that does NOT have bone marrow.
3 species of the family trichechidae
West Indian
Amazonian
West African
Around what time did Polar bears split from Grizzly bears?
343,000-479,000 years ago
Adaptations mammals had to make to become a marine mammal.
Propulsion/locomotion Thermoregulation Diving/breath-holding Communication Osmoregulation Sensory biology
Seawater is ______ more dense than air
800 times
Modes of propulsion
Drag-based (paddling) – Max 50% efficient
Lift-based (Hydrofoils)– Up to 80% efficient
Hydrodynamic Adaptations
Maximize Laminar flow
- Parallel boundary layer flow
- More hydrodynamic critters have a higher “critical velocity”
Decrease drag
- Frictional or viscous drag
- Pressure drag
How do you measure hydrodynamic efficiency?
Fineness Ratio and Reynolds number
Fineness Ratio equation and what value is the most ideal?
Length/max diameter
4.5 is ideal
Reynold’s number
R=(Body length x Swim velocity)/[(Water viscosity)/(water density)]
The lower the R value means the more hydrodynamic it is.
Balaenidae
Right Whales (only 2 species exists)
Eschrichtiidae
Gray Whales (Only 1 species left)
Balaenopteridae
Rorqual whales
Physeteridae
Sperm whale (Only 1 species left)
Kogiidae
Pygmy/dwarf sperm whales
Ziphiidae
Beaked whales
Monodontidae
Belugas and narwhals
Delphinidae
Dolphin
Phocoenidae
Porpoises
Trichechidae
Manatees
Dugongidae
Dugongs
