Lecture 2 Flashcards
study for midterm and final
How long have marine mammals been adapting both physiologically and anatomically?
60 million years
What are some examples of adaptations? (7)
- Locomotion (swimming/buoyancy)
- Skin (type/color)
- Sensory (smell/hearing)
- Respiration
- Cardiovascular
- Movement (propulsion)
- Kidneys (specialized - conserving need for water)
What are the planes that the body is divided up into?
- Anterior (front “head”)
- Dorsal (back “top”)
- Posterior (back end “butt”) (sometimes refered to as caudal)
- Ventral (abdomen “stomach”)
How are fins named where?
Based on body position
(pectoral fins = arms on the side of chest)
(Dorsal fins = if present located on the dorsal plane (back))
(Caudal fins = located on the posterior plane)
List the features of Cetaceans (Whales, Dolphins, Porpoises) (8 things)
- Nostrils (Blow holes) on dorsal side of the head
- Large breath capacity
- Blubber (thermoregulation)
- Cardiovascular adaptations
- body size
- Propulsion
- Stability
- Echolocation
List the features of Pinnipeds (Seals, Sea Lions,, Walrus) (7 things)
- More amphibious (less extreme aquatic adaptations)
- Propulsion (hind legs/flippers)
- Dense fur
- Nostrils
- Dentition (Carnivorous)
- Sensory (vision, touch)
- More Varied diving capabilities
What are the seal fur differences between the earless seal and the eared seal?
Eared Seals have more secondary hairs for warmth than earless seals
List the features of Sirenians (Manatees, Dugongs) (5 things)
- Similar body shape to cetaceans
- Paired nostrils (reduce gas exchange)
- Dense bones (buoyancy)
- Flexible lips with bristles
- Dentition (plant eater)
List of features of Polar Bears (5 things)
- Covered in fur (reduce heat loss)
- Skin coloration is black (absorbs heat)
- Thick layer of fat (fasting and buoyancy)
- Streamlined head and body (swimming)
- Forepaws (swimming)
List of features of Sea/marine otters (4 things)
- Flexible bodies & long tails (allows for movement on land and water)
- Has a high metabolic rate (large food intake compared to body size)
- Densest fur (164,662 hairs/cm2)
- Vision
What is the body shape for MOST marine mammals and what is the exception?
- long and slender to short and tubular
- exception is Polar bear
How do cetacean forelimbs differ from other marine mammals in terms of what we call them?
Cetaceans = fins
Sirenians = flippers + caudal fin
Seals/Walrus = flippers
Otters/Polar Bears = Paws
Which mammals have the largest range in body size?
Whales (from 33m (blue whale) to 1m (newborn Vaquita))
Which marine mammals have the largest range for body mass?
Whales range from 220 tons (Blue Whale) to 6 tons (Minke Whale)
Seals range from 3200 kgs (Elephant Seal) to 45 kgs (Baikal Seal)
What are the 4 base color patterns for marine mammals
- Uniform - mainly one color
- Spotted
- Striped
- Saddled or counter shading
How is the uniform pattern described?
What are the marine mammals that have a uniform color pattern?
- Mainly one color
- Belugas, polar bears, sea otters, manatees
How is striped pattern described?
What are the marine mammals that have a striped pattern?
- Distinct pattern may be along head, side, belly, or flukes
- Pacific white sided dolphin/killer whale
How is the saddled or counter shading pattern described?
Which marine mammals have this pattern?
- Dark on dorsal side and light on ventral side
- Dolphins and whales
What other factors can determine skin color differences
AGE
- Walrus young darken with age
- Beluga young whiten with age
- Harp seals develop pattern over time but are born white
SEX
- Males are darker than females
How are colorations adaptations in marine mammals? Which species belongs to which adaptations?
- Blend into habitat (seals)
- hunting (killer whales, polar bears)
- protection (whales/otters)
- communication (Dolphins - swimming in groups) and (seals - differentiate between sexes)
In Cetaceans what does a bridle consist of?
- a blow hole stripe
- an eye stripe
- flipper stripe
What is a lanugo?
- Fetal pelage (soft fur) usually lost a few days or weeks after birth (in pinnipeds)
What factors determine color in pinnipeds?
- Various colors of hair or pelage
- may change between dry and wet
- between sexes
- physiological changes (constriction/expansion of blood vessels in epidermis)
What external skin features do Cetaceans lack?
- sweat or sebaceous glands
- hair except bristle like hairs around the mouth
What are some external skin features that sirenians have and lack?
- lack skin glands
- have sparse hair on dorsal surface
What are the three layers of skin?
- Epidermis
- Dermis
- Hypodermis
What does the epidermis consist of?
What is unique about pinnipeds?
- Consists of fat, solid keratinized cells
- Protection
- Contains pigmented cells
- In pinnipeds, keratinized cells are lubricated by sebaceous oily glands -> waterproofing
What does the Dermis consist of?
- Contains hair follicles, sebaceous glans, sweat glands and claws
- Well vascularized and contains fat cells
What does the Hypodermis or Blubber layer composed of?
Which marine mammals does it help act as insulation and streamline the body to aid in swimming:?
- Composed of fact cells and collagen which forms the blubber layer
- Walrus, Phocids, Cetaceans and Sirenians
How fast is the epidermis renewed?
- renewed every 2 hours (12 times a day)
- 9 times faster than humans
What marine mammals have the thickest and thinnest blubber layers? Which has NO blubber but large amounts of fat?
- Mysticetes (baleen whales) have the thickest blubber
- Sirenians (Dugongs and Manatees) have the thinnest blubber
- Sea otters and Polar Bears have NO blubber but lots of fat
What happens to dolphins in captivity in terms of vision?
- Vision takes on a more demanding role
- ecolocation reduction
How are the eyelids of cetaceans unique?
- There are glands which produce viscous tears
What spectrum of color vision do Cetaceans have?
Blue/green spectrum only
How do Pinnipeds use their vision differently on land vs in water?
- In water, vision is used for prey detection/avoiding enemies
- On land, eyes play a role in breeding, birth, feeding pups, intrapopulaiton relationships
In captivity what are seals able to recognize?
- seals able to recognize shapes, distinguish small objects and analyze visual images
What spectrum of color vision do Pinnipeds have?
Blue/green spectrum only
In terms of vision, which marine mammals do we know little about?
Sirenians, sea otters, polar bears
What does amplitude of a wave represent?
Amplitude defines brightness
What does wavelength determine?
Color
What are the properties of violet/blue?
Decreased wavelength
What are the properties of red?
Increased wavelength
What is the atmosphere consist of?
- Molecules (Oxygen, Nitrogen, CO2)
- Water (vapor, crystals, droplets)
- solid particles (dust, pollen, salt)
What factors alter atmosphere composition?
- Location
- Weather
- Pollution
- Natural events
How do light rays travel and what color do they appear as
- travel in straight line
- appear as a white light
What two things may happen if light hits an object?
- It will change either amplitutde, wavelength or both
- molecule will absorb some of it and release that absorbed part of the light in a different direction
What are higher frequency colors and how does their absorption compare to lower frequency colors?
- Violets and Blues
- absorbed more frequently than lower frequency colors (red)
What is Refraction?
- process wich light changes or bends after traveling through a different medium
When light goes through water it is slowed down by how much?
30%
How do objects change when looking at them from air to underwater?
Objects underwater appear magnified (larger) and closer than it actually is
What is absorption?
Absorption is the how the light is absorbed by other objects
- 18% of light rays reach a depth of 18 meters
- only 1% of light rays reach 100 meters
