Unit #8 ExamOverall: Average – 82.99% Highest – 109 Lowest – 20

1st: 84.33% 4th: 86.75

2 Failures 2 Failures

100028564 (62) 100022745 (50)

100023842 (26) 100028473 (60)

2nd: 80.87% 5th: 82.65%

3 Failures 2 Failures

100023258 (54) 100023446 (46)

100023161 (64) 100029541 (20)

100038241 (52) 7th: 80.92%

3rd: 87.52% 2 Failures

2 Failures 100023579 (30)

100023608 (55) 100034582 (36)

100023260 (60)

Most Missed Questions:

• A shark that carries its eggs within its body prior to the eggs hatching shortly before birth would be considereda) Oviparous

b) Viviparous

c) Cannibalistic viviparous

d) Placental viviparous

Most Missed Questions:

• Scientists have discovered scales of chondrichthyes that date back to the ____________ period.a) Cambrian

b) Silurian

c) Ordovician

d) Quaternary

Most Missed Questions:• All of the following are true when considering

shark eyes, EXCEPT:a) Melanin helps shield their eyes from bright light

b) The tapetum lucidum covers over the eyes of larger sharks when they bite into prey that could hit and damage their eyes

c) Sharks have eyes that are well developed for detecting prey during the day and during the night

d) The tapetum lucidum helps to amplify light in low-light situations so that the shark can hunt effectively in the dark

Most Missed Questions:

• Chondrichthyes have several potential methods of respiration. The method of respiration that is most similar to our own (human) isa) Two-pump

b) Ram ventilation

c) Lobed-lungs

d) Spiracles

Most Missed Questions:

• Using Chart #2, which chondrichthyan can be found in the greatest numbers in contemporary times (Cenozoic):a) Sharks, rays, and skates

b) Chimeras

c) Modern bony fishes

d) Lungfishes

Figure 24.01

Most Missed Questions:

• Using Chart #2, which chondrichthyan can be found in the greatest numbers in contemporary times (Cenozoic):a) Sharks, rays, and skates

b) Chimeras

c) Modern bony fishes

d) Lungfishes

Most Missed Questions:

• When considering respiration, a stingray uses spiracles and _____________ to breathe.a) Ram ventilation

b) Two-pump ventilation

c) Nictitating membrane

d) Ampullae of lorenzini

Bellwork: 03/23/2012

Collect the following data:• Chlorine (Fresh water only) Salt Water Tanks Only:

Water Hardness• DO - Phosphate• Turbidity - Salinity• Nitrate - Calcium• Nitrite• Ammonia• pH• Temperature

Make sure to clean out any excess food from your filter and gravel/sand. Scrub off the inside of the glass & clean the outside with Windex once you are finished.

Bellwork:

1) The Ampullae of Lorenzini detects:

2) A shark’s olfactory senses can reach up to _________ meters.

3) What is the benefit of a “rete mirabile?” What type of fish would have this?

Bellwork: 03/20/20121) What organisms are considered Pinnipeds?

2) What are two physical differences between seals & sea lions?

3) Name 4 characteristics that are found in all mammals:

Bellwork:

1) Test your water for TAN (nitrate, nitrite, ammonia) & report all values to me.

2) Change 10 to 25% of your water depending on those values.

Marine Mammals

Marine Mammals• Like the marine reptiles and birds before them,

several different types of land animals successfully invaded the ocean:– Seals, sea lions, and the walrus (order

Pinnipedia)– Sea otter and the polar bear (order Carnivora)– Manatees and dugongs (order Sirenia)– Whales, dolphins, and porpoises (order

Cetacea)• 120 species altogether

What is a Mammal?•Mammals have a 4

chambered heart.•Mammals are warm-

blooded.•They have hair/fur.•Have mammary

glands.•Give birth to live

young.

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.

• Pinnepeds live in cold water, they have a thick layer of blubber to keep them warm.

• 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.

Seals• Seals have rear flippers.• They move forward by

pulling themselves along the ground.

• 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.

Weddell seal

New Zealand fur seal

Sea Lions• Are also called Eared Seals,

because they have external ear flaps.

• They can move their rear flippers forward to walk.

• They are graceful and agile swimmers.

• These are the animals that you see at Sea World or an Aquarium doing tricks and they also work for the US Navy.

• At one time they were hunted for their fur, but are now protected by the MMPA of 1972.

Sea lions and fur seals vs. Seals

Sea lions and fur seals (Otariidae)

Seals (Phocidae)

Walruses• Have large

protruding tusks for digging up mollusks.

• They have stiff whiskers for feeling around on the ocean floor.

• They are the largest Pinneped, weighing up to 2700 lbs.

Sea Otters• 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.• They were slaughtered to the brink of

extinction for their beautiful fur, but became protected by an international agreement in 1911.

• They are playful, and intelligent.• They eat mostly shell fish and spend most

of the day maintaining their fur.

Sea Otter• Enhydra lutris

– Native to north Pacific

– 394,000 hairs/cm2

– No blubber– Female 45 lbs; Male

65lbs – Diet: Sea urchins,

abalone, mussels, clams, crabs, snails and about 40 other marine species.

– Uses tools

– Dives to 330 ft

– Rests in coastal kelp forests

Sea Otters

Sea otter as a keystone species

Pop size: 22,000 to 27,000Weight: 550 to 1,700 pounds

Polar BearPolar Bear

Polar Bear• Ursa maritimus

– United States, Canada, Russia, Greenland and on the Arctic islands of Norway

– Male: 10 feet tall and weigh over 1400 lbs

– Female: seven feet and weigh 650 lbs

– wild polar bears live up to age 25.

– Good swimmers

– Thick blubber

– Thick fur

Polar bears

• Polar bears are the least adapted to the marine lifestyle

• Land animals that are adapted to the cold

• Considered marine mammals because they feed almost exclusively on marine organisms

• Very good swimmers, but can’t dive below surface well

• Hunt seals and walruses, occasionally cetaceans

Range: • Circumpolar in Arctic• Range depends on sea ice

• normal range          occasional range over pack occasional range over permanent ice

Polar Bears

• They are semi aquatic, and inhabit both the land and the sea.

• 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.

Sea Otters and Polar Bears

• Sea otters are found only in the Pacific Ocean, and have the densest fur of all animals

• Sea otters inhabit nearshore environments and dive to the sea floor to forage on mollusks, crustaceans and echinoderms (sea stars and urchins)– Must eat ~25-30% of their body weight per day

Polar Bear

• Polar bears are semi-aquatic mammals that spend a good deal of their life drifting on sea ice in the Arctic

• They feed primarily on seals, which they stalk at breathing holes

• World’s largest land carnivore

• Thick blubber; translucent fur, black skin!

• Threatened by the loss of Arctic sea ice!

Manatees and Dugong• Sirenians (order Sirenia) include the

manatees and dugong

• Sirenians, also known as sea cows, have a pair of front flippers, but no rear limbs

• Swim with up-and-down strokes of their paddle- (manatee) or V- (dugong) shaped tails

• Closest land relative is the elephant!

Similar to W. Indian manatee but: blunter snout

more protruding eyes

more slender body

West Indian manatee

West African manatee

Cetacean-like tail

No nails on flippers

<3m long

Dugong

Tusks

Amazonian Manatee

Totally marine

Totally freshwaterWhite patches

Manatees

The Florida Manatee

Dugong

Manatees and Dugong• Sirenians are the only herbivorous marine

mammals; feed on aquatic plants and algae

• Some species live in fresh and/or brackish water

• Inhabit temperate or subtropical waters

• Severely threatened by motor boat collisions, harmful algal blooms, pollution, and severe winters

Dugong Range

10,000

Manatee

9.8 ft, 800-1200lbs3,000 in U.S.

Stellar’s Sea Cow (the sirenian you’ll never see)

• The Stellar Sea Cow was a large, herbivorous marine mammal formerly abundant in the North Pacific

• Described by naturalist Wilheim Stellar in 1741; hunted to extinction within 27 years of discovery!– 8 meters long– Fed on kelp– Did otter hunting

play a role?

MANTEE ECOLOGY

• Nutritionally poor diet• Metabolic rate 20-30 % lower than expected• Primarily plant diet-some times eat fish captured in nets & tunicates

• Predation low: crocodiles/alligators and sharks

• Most mortality: coldred tidesboat collisionby-catch

Cetaceans• This is the largest group of Marine

Mammals, consisting of Whales , Dolphins, and Porpoises.

• These, of all the Marine Mammals, have made the most complete transition to aquatic life.

• These animals spend their entire lives in the water.

• They are streamlined, and look remarkably fish-like.

• They breathe air through lungs and have nostrils on the tops of their heads called a blowhole (some single, some double).

• There are more than 90 species of Cetaceans.

• They are divided into two groups: toothed Whales (which includes Dolphins and Porpoises), and toothless Whales which have a Baleen.

• Instead of teeth, Baleen Whales have rows of flexible, fibrous plates, that hang from the upper jaws (called a Baleen). These are used to filter out plankton and tiny organisms from the water.

• Baleen Whales are the largest animals to ever have lived on this planet.

• There are 13 species of Baleen Whales, the Blue Whale being the largest at up to 110 ft. long, and up to 200 tons.

• The remaining 80 species of Cetaceans are toothed Whales.

• Their teeth are adapted for a diet of squid, fish, and other prey.

• Teeth are used to catch and hold prey, not to chew it.

• The largest of the toothed Whales is the Sperm Whale, made famous by the novel “Moby Dick”.

• Killer Whales, or Orcas, are predators, eating seal, penguins, sea otters, and fish.

• They are more common in cold water, but are found round the world.

• Voluntary breathing – must be conscious to open blow hole.

• A few species sleep as such:– Right whales (very buoyant)– Sperm whales (float – do not have to breathe

for hours at a time)

• Duplication of brain function – part of brain can sleep while another part awake.

SLEEP

How do Cetaceans reduce drag for fast swimming?

• Fusiform body– Tapered at both ends

• Paddle-shaped front limbs• No external digits or claws• Tail flattened laterally and bearing horizontal

flukes at the tip• Vestigial ear pinnae• Hairless body• Thick subcutaneous blubber layer filled with

fat and oil

• Dolphins are highly intelligent creatures, and can be easily trained.

• They are very playful, and have been known to “escort” ships for miles at a time.

• Porpoises have flattened spade-like teeth and shorter noses than dolphins

• Dolphins, Porpoises, and Whales travel in groups called Pods.

• They are protected by the MMPA of 1972, but are still hunted.

• The Japanese, and Norwegian fishing Industries have been illegally whaling under false pretenses (scientific whaling).

• It is common for Cetaceans to get caught in fishing nets meant for other species.

Coping with Cold Climates

• Small cetaceans – Have high metabolic rates– Flippers and flukes have a

countercurrent heat exchange system

• Heat from arterial blood warms venous blood as it returns to the heart

• Large cetaceans– Small surface to volume ration

• Lose little heat to the surrounding environment

• Both are insulated by thick blubber layer

Physiological Adaptations for Deep Diving

• Rapid exchange in lungs– Enhanced by double capillary layer in the

intraalveolar septae– Humans use 4% of Oxygen inhaled,

Cetacea use 12% – Twice the number of erythrocytes and

myglobin molecules in their blood• Allows for efficient capture and transport of

oxygen

Cont.

• Alter blood distribution– Rate of flow slows down (Undergo bradycardia)

• Heart rate slows by as much as 80 beats per minute

– Eliminated at non-critical organs via shunts• i.e. digestive tract

– Reserved for critical tissues• i.e. heart and brain

• High tolerance to Carbon Dioxide and lactic acid build up in tissue

Taxonomic History

• Hippopotamids are closest living relatives– Followed by ruminants

• i.e. cows

Communication• One way Cetaceans communicate is

through Echolocation.• They release tiny bubbles through their

blowholes and make clicking sounds to communicate with each other and determine distances, and warn others about danger.

• This is natures version of Sonar.• The Melon (fatty structure on the top of

their heads) focuses and directs these sound waves.

• Cetaceans produce a rich variety of sounds tha are associated with different moods, sexual signaling, feeding, alarms……

• Harbour porpoise – 15 years• Bottlenose dolphin – 50 years• Killer whale – 90+ years

• But only 20-25 years in captivity• Blue whales - 100+ years• Bowhead whales – 218 years +

Long life cycles and low reproductive rate Long life cycles and low reproductive rate means that the recovery of depleted means that the recovery of depleted

populations is slowpopulations is slow

LONGEVITY

Social behavior

• Highly sociable within their respective species; often forming pods– Pods often collaborate in hunting, playing,

traveling, and taking care of young– Usually remain in pods throughout their life– Pods are beneficial because hunting is

easier in a group; also pods decrease predation

Communication

• Flukes or Flippers– Slap the surface

• Breaching– Leaping from the waters

surface– Helps them to attain an

elevation of several yards

• Spy-hopping– Raise head out of water to

investigate objects or potential prey

Breaching• When Whales leap in the air and

loudly crash on the surface of the water.

• This can be a warning signal, getting rid of external parasites, fun, or a way of scanning the surface.

Ecosystem Roles

• Vital roles as consumers • Host a range of internal

parasites– Cestodes in their intestines

(Tetrabothrium and Diplogonoporus)

– Plerocercoids in their blubber (Phyllobothrium and Monorygma)

– Trematodes in their stomachs, livers, intestines, and sinuses (Bolbosoma)

• Host a range of external parasites– Cookie-cutter sharks (Isistius

brasiliensis)

Cont.

• Cetaceans are mutualists with animals that feed on ectoparasites

• Birds have a commensal relationships with cetaceans– Seagulls often follow schools of dolphins and

consume small fish stirred up by the feeding cetaceans

– Pilotfish (Naucrates ductor) sometimes accompany killer whales and eat scraps from their kills

Economical Importance for Humans

• Disadvantage– Impact commercial

fisheries due to competition for fish

• Advantage– Hunted for meat, oil, and

blubber in 19th century• Oil is used for lighting and

heating

– Important for entertainment and tourist industriesKiller Whale – Orcinus orca

www.destination360.com

Bellwork – 03/22/2012

1) What is echolocation & which organ helps focus the sound used in echolocation?

2) Which marine mammal has the most dense fur?

Whaling• 1600’s Europeans exploited whales in North Atlantic• Americans dominated whaling industry.• Hunted for blubber which was used to make soap

and lamp oil• Baleen used for making stays on corsets.• Explosive harpoon developed in 1800’s• Right Whales first to be seriously depleted. Slow-

swimming, floats after being harpooned.

Whaling• 1900’s Whaling moved to Antarctic feeding grounds.

Reached its peak in 1930’s Estimated that more than 1 million whales killed in Antarctica.

• Blue whales yielded more than 9000 gallons oil. 30,000 blue whales killed during 1930-31 season, 200,000 killed between 1924 and 1971.

Whaling (cont.)

• 1946 – International Whaling Commission set up by 20 countries to stop “over-fishing”. Collected data on whale numbers from whalers, set non-binding, annual quotas.

• After WWII - Demand for whale oil dropped, due to substitutes created. Whale meat still in demand by pet-food industry and Japanese kujiraya or whale-meat bars

• 1972 U.S. passed Marine Mammal Protection Act which bans hunting of all marine mammals(exception are Alaskan native fisheries) and importation of all marine mammal products.

Whaling (cont.)

• 1974 IWC protected blue, gray, humpback, right whales• 1985 moratorium declared on all commercial whaling by IWC.• 1987 Soviet Union halted all whaling/1988 Japan, Iceland and

Norway opted to continue whaling of minke, fin and sei whales under “scientific whaling”. Iceland dropped out of IWC

• 1994 IWC members created Antarctica as sanctuary, main feeding ground of 80% of remaining great whales.

Dolphins and Man

• Dolphins are being substituted for whales by some countries. Not protected by IWC

• 28 species are in immediate danger of extinction• Vaquitas – small, shovel-nosed porpoise of Gulf of

California – only 200 to 500 left.• Depleting fish and squid on which dolphins feed.• Peru – dolphin meat cheaper than beef or chicken• Tuna Fishermen – use purse seine nets and drift

nets which trap and drown many dolphins

Purse Seine and Drift Nets

Drift net

Purse seine net

Closing Purse Seine Net

Fishing