Unit 9 Exam Review

Review• Characteristics of Mammals – – Mammals have a 4 chambered heart.– Mammals are warm-blooded.– They have hair/fur.– Have mammary glands.– Give birth to live young.

Review• Pinnepeds – – Pinnepeds are marine mammals that

have flippers and blubber, that need to breed on land.

– Seals, Walruses, and Sea Lions all belong to this Order.

– They are mostly carnivores and feed on squid and fish.

– They have streamlined bodies and are excellent swimmers.

– Seals are the largest group of pinnepeds.

Review• Carnivora– – For this unit: this order included polar

bears and sea otters– These organisms have dense fur,

blubber, or both to keep themselves insulated in and our of the water

– Feed almost exclusively on meat

Review• Sirenia – –Manatees and Dugongs– also known as sea cows, have a pair of front

flippers, but no rear limbs– Herbivorous– Live in brackish water– Most common methods of death are boat strikes

and red algae blooms (red tides)

Review• Cetaceans –– The largest group (both in size and in numbers) of

aquatic mammals– Divided into Baleen Whales and Toothed Whales– Included dolphins, whales, and porpoises– Spend their entire lives in water– Most adapted mammal for aquatic life

Review• Seals – – Limbs are not suited for walking on land .– Seals do not have ear flaps.– They are hunted for their fur and are protected

by the Marine Mammal Protection Act of 1972.– There are approximately 19 species of Seals

(most diverse pinniped).

• Sea Lions – – they have external ear flaps.– Limbs are suited for walking on land.– MMPA of 1972

Review• Walrus –– Have large protruding tusks for digging up

mollusks. – They have stiff whiskers for feeling around on

the ocean floor Thigmoreceptors).– They are the largest Pinneped, weighing up to

2700 lbs.

• Sea Otter – – They are the smallest Marine Mammal,

weighing 60-80 lbs.– They lack a layer of blubber, and make up for it

by trapping air in their dense fur.– protected by an international agreement in

1911

Review• Capstone/Keystone species:– A species that has a disproportionate impact on

stabilizing its environment– Example: Sea otters They eat sea urchins and

are eaten by ocras. If they disappear, the sea urchins eat all the plant life, bottom out the food chain, and the system as a whole suffers a great reduction

Review• Polar Bear – – They feed primarily on seals.– They have recently been put on the

endangered species list because of loss of habitat due to global climate change.

– Least adapted for marine life (not good divers due to blubber) but are considered marine based on their diet

Review• Marine Mammal Protection Act (MMPA,

1972)– Established in response to crashing cetacean populations– This act makes the hunting of any cetacean illegal, except

for traditional American hunters such as Native Alaskans

• Manatees – – Can be found around Florida and the Gulf of

Mexico – Vestigial nails on front flippers– Rounded tail

Review• Dugong – – Found around Australia and Eastern Asia– V-Shaped tail

Review• Baleen Whales vs. Toothed Whales:– Baleen – filter feeders• Includes the largest animals on the planet• Tend to live alone• Communicate over long distances using low frequency

sound• Migratory

Review• Baleen Whales vs. Toothed Whales:– Toothed Whales – active hunters• Smaller & more social• Most are not migratory• Use sound for echolocation of food & communication

with other members of the group

• Cetaceans & Sleep:– Voluntary breathing– Duplicated brain function for “active sleep”– Right whales & sperm whales can sleep in a more

traditional manner

Review• Contemporary Whaling Countries:– Japan– Iceland– Norway– Faroe Islands

• Grindadrap – – Traditional annual whaling event in the Faroe

Islands– Up to 1,000 whales killed/hunt– Majority of biomass is discarded since the meat is

no longer considered safe to eat

Review• Coping with cold:– Smaller cetaceans have higher metabolic rates

(generate heat faster)– Countercurrent exchange system in flippers and

flukes– Large cetaceans have a small surface area to

volume ratio– Both have a thick layer of blubber for insulation

and buoyancy

Review• Physiological adaptations for deep diving:– 12% oxygen uptake compared to a human’s 4%

oxygen uptake– Twice the number of erythrocytes (red blood cells)

in their blood– Slow heart rate– High tolerance for lactic acid and carbon dioxide

Review• Cetacean Communication:– Sound is generated by passing air over the vocal

cords of the organism– The sound is focuses and amplified in the melon– When sound returns it is absorbed by mandibular

fat– The vibrations in the fat are transmitted to the

auditory bulbs and relayed to the brain

Review• Cetacean Communication:

Review• Cetacean Communication:

Review• Whaling in the 1930’s– Whaling in the Antarctic began on an industrial

scale during this decade– The Antarctic was/is a common breeding and

feeding ground for many large baleen whales– Over 30,000 blue whales (the largest animal on

the planet) were killed for their oil in the 1930-1931 hunting season

– Its estimated the over one million whales were killed in the Antarctic in the 1930’s

Review• International Whaling Committee:– Established in 1946– Created to regulate/make quotas for hunted

whales to prevent seasonal over fishing

• 1985/1986 Moratorium– Passed by the IWC banning all commercial whaling– Scientific Whaling is permitted & exploited by

Norway & Japan– Toothed whales (small cetaceans) are not covered

in this moratorium

Review• Scientific Whaling:– A loophole in the whaling moratorium allows for

whales to be killed and harvested for scientific reasons

– Japan and Norway exploit this loophole to kill & sell large cetaceans

• Cetaceans as Food:– Some countries consider cetacean meat a delicacy– In other countries, only the poor consume

cetacean meat based on its price– In both circumstances, the meat consistently

contains dangerously high levels of mercury (Hg)

Review• Echolocation – – A cetacean’s use of sound to find & gather information

concerning predators & prey

• Pitch – – Frequency, determined by wavelength– Lower pitched sounds will travel further in water

• Frequency – measured in hertz (Hz)

Same frequency,Different amplitude

Review• Loudness – – Determined by size of amplitude– Measured in decibels (dB)

• Amplitude –

• Air/Water decibel comparison –– Sound levels in air and water have different reference

levels, so – 0 dB (air) ≈ 26 dB (water)

Same amplitude,Different frequency

Review• Different acoustic targets for echolocation – – Squid and large fish are:

• More likely to be solitary• Good acoustic targets

– squid mantle and fish swim bladders have density different from water

– Plankton are:• More likely to aggregate• Poorer acoustic targets

– density similar to water

• Snapping Shrimp – – Snapping shrimp make noise to stun their prey.– They create a cavitation bubble that “snaps” as it

collapses.

• Atlantic Croaker – – Some fish use sound for courting and as a fright response

Review

Review• Toothed Whales & Sound– – Used for communication & echolocation– Create squeaks and songs for communication (102.25 to

104.25 Hz)– Create clicks/cracks for echolocation of food (104 to 105.25

Hz)

• Baleen Whales & Sound– Use sound for communication only (10 to 103 Hz)– Their calls/songs can potentially be heard by other

organisms hundred of miles away– Significant disruption by man-made noise

Review• Frequencies of SONAR and air guns – – Airgun

• 10 to 500 Hz• Up to 232 dB

– Low-Frequency Active Sonar• 100 to 500 Hz• 230 to 240 dB

Review• Noise-induced mass strandings: • Many Examples• Seismic Testing & Strandings in Peru (2012):– Northern Peru (February 2012)– 900+ dolphins stranded or washed ashore dead• Middle Ear Bleeding• Cracked bones in ear• Hemorrhage in mandibular fat• Air bubbles in liver, kidneys, bladder, and blood vessels• Pulmonary emphysema– * The last two are associated with acute decompression

syndrome