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“Study nature, not books” (Louis Agassiz) . Bi 1 Lecture 29 Thursday, June 2, 2005 Evolution 3. Voyages to the Galapagos; The physiology of Diving Mammals. Announcements on the Bi 1 Web page: http://www.its.caltech.edu/~bi1/schedule.html.

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“Study nature, not books” (Louis Agassiz)

Bi 1 Lecture 29

Thursday, June 2, 2005

Evolution 3. Voyages to the Galapagos;

The physiology of Diving Mammals


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Announcements on the Bi 1 Web page:

http://www.its.caltech.edu/~bi1/schedule.html

Review Session takes place here, today, here, 4 - 6 PM.

Sections meet as usual today and tomorrow.

The final exam is posted Thursday (today) 6 PM;

Due Fri 6/10 4:30PM in the Bi 1 Closet

Graduating seniors: papers are due today 5 PM in the Bi 1 Closet


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Acknowledgements

“It takes a village to teach Bi 1 at Caltech”

TAs, both grads and undergrads

Professional staff:

Dr. Jane Mendel, Head TA: Sections and grading

Patricia Mindorff, communications

David Mathog, Molecular Graphics

Eric Slimko, Webmaster

Biology Electronics shop computer support:

Mike Walsh and Pam Fong

Guest lecturers:

Robert Freedman

David Anderson

Cameo appearances from Biology Faculty

Advice from other Core Curriculum Resources

You, the students


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The Voyage of the HMS Beagle 1831-1836

Charles Darwin (born 1809), unpaid naturalist

Azores

Cape Verde Islands

Canary Isles

Cocos Islands

Tahiti

Bahia

Rio de

Janeiro

King George

Sound

Cape of Good Hope

Galapagos

Islands

35 day visit

Valparaiso

Montevideo

Tasmania

New

Zealand

Falkland Islands

journey out

journey home

Cape Horn


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Equator

Punta Espinoza

Age of the archipelago:

~ 1 million yr

British Admiralty chart of the Galapagos Islands, based on the Beagle’s observations


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Darwin’s Finches(5 genera, including Geospizia)

cactus finch

ground finch

tree finch


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The voyage of the Beagle convinced Darwin that

1. Members of the same species often change slightly in appearance after becoming geographically isolated from each other

2. Organisms living on oceanic islands often resemble organisms found living on a close mainland

3. Factors other than or in addition to climate play a role in the development of plant and animal diversity

4. Organisms of the past and present are related to one another (but there are no fossils in the Galapagos)


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"The distribution of the tenants of this archipelago would not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."

Darwin, The Voyage of the Beagle

http://www.literature.org/authors/darwin-charles/the-voyage-of-the-beagle/chapter-17.html


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Finch family tree based on a 660-nt sequence not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."

Molecular Biology and Evolution 18:299-311 (2001)

Darwin’s

Galapagos finches

.01 change per position


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Red-Footed Booby not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."

(Ben Lester)

Blue-Footed Booby


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Masked booby not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."

A recently discovered a behavior, called siblicide, occurs among booby chicks.

The larger chick always kills the younger chick, sometimes aided by the parents.

Scholars debate the selective advantage of such behavior.

Perhaps the parents succeed better by insuring the survival of at least one chick.


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Male Frigate Bird Displaying not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."

no oil on feathers

cannot land on water

steals other birds’ fish


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Galapagos Waved Albatrosses in Courtship not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."

2 m wingspan


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Video of Galapagos Waved Albatrosses in Courtship not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."


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photo by not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."

Ben Lester

Female Albatross on the nest


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photo by not be nearly so wonderful, if, for instance, one island had a mocking-thrush, and a second island some other quite distinct genus.... But it is the circumstance, that several of the islands possess their own species of tortoise, mocking-thrush, finches and numerous plants, these species having the same general habits, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder...."

Ben Lester


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The Galapagos tortoises reach sexual maturity at the age of 40

and have clutches of 2 - 26 eggs.

Eggs hatch at 85 -180 d.


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Galapagos Penguins 40

World’s Northernmost population of penguins.

After "El Nino" in 1983 the population decreased from 12,000 to just 2,000 birds.



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Marine Iguana feeding 40

Marine iguanas feed once a day.

The mature lizards swim out through the tidepools to dive to the bottom for algae; smaller iguanas feed off the rocks in the tidal zone.

An iguana may lose up to 10 degrees C of body temperature on these feeding missions. Because they are cold-blooded ("ectothermic") , iguanas must bask on the hot lava rocks throughout the day until they raise their internal temperature.


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The increased rainfall that accompanies El Niño results in greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Green and red algal species, which are the marine iguanas' preferred food, disappear and are replaced in intertidal areas by brown algae which iguanas find hard to digest. Up to 90% of marine iguana populations on islands can die of starvation as a result of these environmental changes.

During a recent El Niño event (1997–98), larger individuals of the two island populations shrank more than smaller individuals. The scale of the shrinkage — up to 20% of body length — means that it cannot simply be explained by decreases in cartilage and connective tissue, which together make up only 10% of total body length. Apparently bone absorption accounts for much of the reduction.


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The fight against salt at Punta Espinoza: greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

marine iguanas

cormorants

sea lions

Marine Iguana


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salt crystals greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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Flightless Cormorant drying its feathers at Punta Espinoza greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

large flightless birds are common on islands, e.g. kiwi (New Zealand)

extinct:

Great auk (north Atlantic), dodo (Mauritius),

solitaire (Reunion, Rodrigues), moa (New Zealand)


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California Sea Lions greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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short-eared owl (flies) greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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Flamingos in a salt marsh greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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Pelicans greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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Land iguana greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen. (Conolophus sp)


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Lava lizard doing pushups greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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Territorial iguana chase greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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Sally Lightfoot crab greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Resembles black crab of Hawaii’s Big Island


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stingless bee greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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Pinnacle Rock on Bartolome: greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Excellent diving, lots of marine life


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The Physiology of Diving greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.


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Emperor penguins greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Aptenodytesforsteri

550 m

22 min

typical: 2-10 min, 50-500 m


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Elephant seal greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Mirounga leonina

1600 m

120 min

typical: 20-30 min, 200-800 m


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Weddell seal greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Leptonychotes weddellii

> 600 m

82 min


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Bottlenose dolphin greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Tursiops truncutus

210 m

5 min

typical 30 m, 120 s


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Blue whale greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Balaenoptera musculus

300 m

50 min


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Sperm whale greater food availability for most terrestrial organisms in the Galápagos, but marine life generally suffers from the higher water temperature, which decreases the amount of dissolved oxygen.

Physeter macrocephalus

3000 m

90 min


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In metabolism, electrons move around inside cells until they reach oxygen,

which has the highest electron affinity of the biological elements

Little Alberts 2-7

© Garland


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Emperor penguin reach oxygen,

Baikal seal

Weddell seal

In the absence of oxygen,

glucose ®

pyruvate and lactic acid.

~ 2 moles of ADP are converted to ATP.

In the presence of oxygen,

glucose + O2® H20 + CO2.

~ 24 moles of ADP are converted to ATP

enzymes and carriers transfer 40% of the bond energy to high-energy phosphate bonds, in small steps.

Diving mammals must store oxygen in order to conduct aerobic metabolism


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two oxygen-carrying heme proteins reach oxygen,

Diving mammals have much higher:

blood volume

hemoglobin concentration

and especially myoglobin

than other mammals.

More than 80% of the oxygen is in the blood and muscle.


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two oxygen-carrying heme proteins reach oxygen,

Diving mammals have much higher:

blood volume

hemoglobin concentration

and especially myoglobin

than other mammals.

More than 80% of the oxygen is in the blood and muscle.


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Crittercam (UC Santa Cruz) reach oxygen,

35 cm

batteries

and

computer

detachable

CCD

camera

8 mm

tape recorder

lens

float

transmitter

Ti or Al

housing

900 nm LEDs

fins

Audio channels

(1) accelerometer

(2) microphone

Transducers for pressure, water speed, and compass bearing are sampled once per second, and the data are stored on a PCMCIA card. A separate housing (17 cm long and 5.5 cm in diameter) for the gimbaled flux-gate compass is positioned behind the main housing and connected to it with a cable.


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Diving mammals reach oxygen,glide much of the time




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Pressure effects on air gases during a dive

10 m = 1 bar

Sport diving is limited to ~ 40 m

1. The bends: N2 bubbles form in the blood

2. Nitrogen narcosis

3. Oxygen toxicity


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Tanks during a dive200 bar

Regulators


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Some compressed air remains in the windpipes, but a collagen lining prevents absorption by the blood

complete peripheral collapse

at 20-50 m

Diving mammals don’t get the bends: adaptations to pressure

“Lungs are a liability for deep divers because, in contrast tomuscle and blood, they are a better nitrogen storethan oxygen store.”

a. flexible chest;

b. no collagen in the smallest branches

“The early occurrence of lung collapse in sealsmakes the lung almost useless as an O2 store, whereas it limitsN2 absorption during the dive.”


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Other effects of water’s high density lining prevents absorption by the blood

1. Heat capacity and heat conduction

Diving mammals solve this problem with blubber.

Scuba divers use exposure suits (wet suit, dry suit).

Both of these materials compress at depth, increasing the animal’s density and providing negative buoyancy.

2. Greater index of refraction

3. Greater speed of sound

4. Greater light absorption


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apparent lining prevents absorption by the blood

object

q’

q’

q

q

2. Objects look larger to a diver (Phys 2a)

real

object

water

n’ ~ 1.3

air in mask

n = 1

nsinq = n’sinq’


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Sound travels lining prevents absorption by the blood

3-4 times faster in water

3. A diver cannot judge sound direction

delay between the two ears

~ 7 sin q ms

(can be determined

to within ~ 10 ms)

q

20 cm

0.2 m/(300 m/s)

~ 7 ms


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4. Objects look blue to a diver lining prevents absorption by the blood

a few m of water absorbs

long wavelengths

shorter wavelengths

penetrate further


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A Summary of Adaptations in Diving Mammals lining prevents absorption by the blood

1. Compressible lungs: decrease buoyancy, decrease bends

2. High myoglobin concentration

3. Blubber

4. “Intermittent locomotion” = gliding

6. Decreased heart rate decreases heat flow

5. Wave riding and jumping

6. Countercurrent cooling devices for testes


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Darwin, lining prevents absorption by the bloodThe Voyage of the Beagle

Darwin, The Origin of Species

Michael Jackson, Galapagos, University of Calgary Press, 1994

Jonathan Weiner, The Beak of the Finch: a Story of Evolution in our Time,

Knopf, 1995


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