Biologi Laut - Mammalia

7/27/2019 Biologi Laut - Mammalia

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Marine Mammals

Erwin R Ardli


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Return to the OceansMammals have returned to the oceans multiple

times

Adaptasi

vivipary

suckling young

thermoregulation

feeding

diving

osmoregulation

Well look at adaptation in marine

mammals from the least to the most


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Adaptations for diving

Exchange a large amount of air on each breath

Up to 90% in each breath (humans exchange about

20%) Blood with more oxygen carrying capacity

Heart rate slows

Blood flow shunted

Higher concentration of myoglobin in the muscles Collapsing lungs

Dive with no air in contact with blood vessels to avoid

problems of nitrogen being forced in


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Fusiform Shape and Streamlining

Evolutionary Convergence


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Two basic bioenergeticstrategies used by animals :

Endothermy warm blooded Ectothermy cold blooded


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Countercurrent Exchange

Concurrent exchange

Countercurrent exchange


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Marine Mammals


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Marine mammals

Karakteristik: Warm-blooded

Breathe air

Have hair (or fur)

Bear live young

Females have mammary glands that

produce milk for their young


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Marine mammals: Order Sirenia

Sirenian characteristics: Large body size

Sparse hair all over body

Vegetarians

Toenails (on manatees only)

Includes: Manatees

Dugongs


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Manatee & Dugong

Most complete transition to marine lifealong with whales and dolphins

Related to the elephant, but common

ancestor didnt look like either of them

Once many more species around Large layer of blubber

Origin of the mermaid myth

Herbivores

Nostrils on top of snout have valves tokeep water out

Both species have one calf at a time

Tend to have a single calf every 3 years


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Location:coastal and inland watersof the western Indo-Pacific region

Dugongs are exclusively marine

and have a dolphin-like tail

Dugongs tend to dig seagrass

rhizomes

Predator includes tiger sharks

Dugong


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Dugong Range

10,000


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Family Dugongidae

Dugong dugong Steller's Sea CowtHydrodamalis gigas

Discovered 1741,

extinct 1768.

8.9 ft, 551-661lbs

30ft, 4.4 tons


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Location: Florida, Central and South

America

Manatees have paddle-like tails

and frequent freshwater

Manatees tend to crop and grabwith prehensile lips

Manatees are larger than dugongs

Few predators

Threats:

Careless boaters

Habitat loss

Manatee


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Manatee

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


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Million of years before present

80 60 40 20 0

Ancestral

mammals

Asian elephant

African elephant

tmammoth

tmastadon

Dugong

tStellars sea cow

West Indian manatee

Brazilian manatee

West African manatee

Other mammals

Relationship

between Sirenians

and elephants

(mtDNA)


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Marine mammals: Order Carnivora

All members of order

Carnivora have

prominent canine teeth

Includes:

Sea otters

Polar bears Pinnipeds (flipper-footed)

Walrus

Seals

Sea lions/fur seals

Hawaiian Monk Seal


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Sea Otter


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Sea Otter Enhydra lutris

Native to north Pacific

394,000 hairs/cm2

No blubber

Female 45 lbs; Male65lbs

Diet: Sea urchins,

abalone, mussels,clams, crabs, snailsand about 40 othermarine species.

Uses tools

Dives to 330 ft

Rests in coastal kelp

forests


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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


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Pinnipeds

Pi i d


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Sea Lion

Walrus

Family Phocidae

Family Otariidae Family Odobenidae

Hawaiian Monk Seal

Pinnipeds
http://www.psrc.usm.edu/macrog/sea/images/walrus.jpghttp://www.psrc.usm.edu/macrog/sea/images/walrus.jpg


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Order Pinniped(seals, sea lions, & walruses)Family Phocidae- true, earless seals

Family Otariidae- eared seals and sea lions

Family Odobenidae- walruses

34 known species

Evolved 20 mya from Order Carnivora (ancestors of dogs

and bears)

Differ in possession of external ears and mode oflocomotion

Biology and Natural History


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Family Phocidae

Hawaiian Monk Seal

Lack external ears Hind flippers propel them while swimming

Front flippers act as rudders

Travel on land is difficult (wiggle)


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Sea Lion

Family Otariidae

Eared seals Front flippers propel animal when swimming

Rear flippers act as rudders

Fairly mobile on land


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Walrus

Family Odobenidae

Found in Arctic region

Lack external ears

Paddle with front flippers

Rear flippers act as a rudder

Fairly mobile on land


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Pacific walrus is in lavender, Atlantic walrus is

in rose.

Walrus Range Map


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Walrus Facts

Location:

Bering sea, Pacific Ocean, Atlantic Ocean, Arctic Ocean

Pop Size:

250,000

Size: Weight:2,000-3,500 lb.

Breeding:

Sexually mature late

- females, usually 6-7 years

- males, 15 years.

Produce few offspring


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Walrus Facts

Lifestyle

Habit: Gregarious, living mainly

in herds.

Diet: Benthic suction feeders.

Feed mainly on bivalve

mollusks, but also other

invertebrate marine animals,

fish, sometimes seals and

whales. Predators:polar bears, killer

whales, and humans

Lifespan:Up to 40 years.


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Walrus Facts Swim speed: 7-35 kph

Tusks:

- Both male & female- Used for dragging body across land or ice

- Symbolize age, sex, and social status

Pharyngeal pockets:

- 2 found on either side of the esophagus that hold upto 50 liters of air ).

- For buoyancy; these pockets facilitate sleep in the

water in an upright position

- May be used to amplify mating calls


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Whales, Dolphins,

& Porpoise


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Whale Evolution


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Marine mammals: Order Cetacea


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Two suborders of order Cetacea

Suborder Odontoceti (toothed whales) Echolocate (send sound through water)

Includes killer whale, sperm whale, dolphins,porpoises, and many others

Suborder Mysticeti (baleen whales) Have rows of baleen plates instead of teeth

Includes blue whale, finback whale, humpback

whale, gray whale, and many others

(55 mya- entered sea)


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Differences between dolphins and porpoises

Dolphins have:

An elongated snout

(rostrum)

A sickle-shaped (falcate)

dorsal fin

Conical-shaped teeth

Killer whale

jawbone


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Echolocation

Sensing environment

Produce clicksthat travel out, hitobjects and reflect back

Produced by a structure in the airway

called the monkey lips

Sound received through the lower jaw

Low frequency clicks travel further but

can only be used for big objects

High frequency clicks can discriminatesmall objects but dont travel as far


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Deepest Diver

(3km~1.5 miles)


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Mysticeti: The baleen whales

Mysticeti whales have baleen instead of teeth

Baleen plates:

Hang as parallel rows from the upper jaw Are made of keratin

Are used as a strainer to capture zooplankton

Allows baleen whales to eat krill and small fish by the ton


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Baleen


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Types of baleen whales

Baleen whales include three families: Gray whale (a bottom-feeder with short baleen)

Rorqual whales (medium-sized baleen)

Balaenopterids (blue whales, finback whales, and otherlarge whales )

Megapterids (humpback whales) Right whales (surface skimmers with long baleen)


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Whale Migration


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Whale Carcass Removal

Biologi Laut - Mammalia

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