What is high-altitude
cerebral edema
(HACE) ?
Way Down Low – Resource Sheet 2, Part 2
What are the
environmental
factors that affect
humans living at
high altitude?
Are there any
genetic adaptations
which allow
organisms to live a
low altitudes?
Why do humans get
sick at high
altitudes?
What is
hypoxia?
An altitude above 7500
metres is described as the
death zone as it is difficult
for humans to acclimatise at
such great altitudes. Are
there climbers that have
made it this far? If so, were
there any physiological or
anatomical adaptations to
their bodies?
Are there any
symptoms?
What is highaltitude
pulmonary
edema (HAPE)?
What is mountain
sickness and when
does it occur?
Are there any
symptoms?
Diphosphoglycerate (DPG) is present in red blood cells . It binds to deoxygenated
hemoglobin, thus promoting the release of oxygen from red blood cells carrying
oxyhaemoglobin.
ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
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Resource Sheet 2, Part 2 (continued)
Free diving is a sport in which human beings use fins but no extra weights to dive as deep as they can . It is known as the
constant balance technique. In 2002 a world record was set by Audrey Mestre when she dived 171 metres in 1 minute 42
seconds. On a second attempt to break her own record she died.
As well as the risk of drowning, terrestrial mammals such as humans are also at risk of getting the bends.
Modifications of lungs, muscles and blood, with tolerance to high carbon dioxide and lactic acid concentrations, as well as a
pronounced slowing of the heart beat, are some of the accomplishments that have resulted in the successful invasion by air breathing animals of aquatic environments. These adaptations have extended the vertical range of mammals to over 1000 metres
below the surface of the ocean, where they exist in low-oxygen niches.
In humans tissue in the limbs can be deprived of oxygen for 30 minutes without damage. The nervous system , however, in
particular the part that is involved in consciousness , cannot function once it has been deprived of oxygen for a few seconds.
When deprived of oxygen humans get a build -up of carbon dioxide and acidity in the blood.
When diving we hold our breath and if we do not surface in time we can drown due to suffocation and loss of c onsciousness,
which leads to hypoxia.
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ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
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Way Down Low – Resource Sheet 2, Part 2
Pinnipeds
Weddell seal
The Weddell seal is a large marine mammal that lives in
Antarctic waters and on fast ice (ice anchored to land). It
is a pinniped (related to the walrus, sea lion and elephant
seal) that does not migrate.
The Weddell seal of
Antarctica routinely
plunges to 200–500 m and
remains there for 20
minutes.
Elephant seals reach
depths of 1500 m (almost
1 mile) and can remain
submerged for as long as
2 hours.
Diving
Pinnipeds are able to hold their breath for nearly 2 hours underwater and dive to a depth of 500 metr es by conserving oxygen.
When the animal starts to dive its heart rate slows to about one-tenth of its normal rate. The arteries squeeze shut and the sense
organs and nervous system are the only organs that receive normal blood flow. Pinnipeds are able to resist more pain and
fatigue caused by lactic acid accumulation than other mammals. However, once they return to the surface, they need time to
recover and normalise their body chemistry.
As marine mammals dive deeper and deeper the pressur e on their bodies increases dramatically. Weddell seals avoid the bends
because their lungs are small for their weight, therefore store less nitrogen (nitrogen diffuses into the blood, causing the bends) .
The seal also exhales before submerging. Can you think of a reason for this?
ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
© Learning and Teaching Scotland 2011
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Resource Sheet 2, Part 2 (continued)
The bends occur in humans once a diver has spent a substantial time under water and
the nitrogen in the body goes into solution. If the diver a scends too quickly the
nitrogen forms tiny bubbles in the blood that can cause painful symptoms and, in
extreme cases, death.
Adaptations of the Weddell seal:
As pressure increases with dive depth (approximately 50 –70 metres) the seal’s rib
cage and lungs collapse. This forces any nitrogen present in the alveoli into the
bronchiolar system. This system has no access to the blood supply; gas can therefore
be stored here without a risk of it diffusing into the bloodstream. The bronchiolar
system is reinforced with rings of cartilage, preventing them from collapsing under
high pressure. In comparison, human bronchi and bronchioles would collapse under
high pressure and cannot store excess nitrogen.
 They store large amounts of 02
(twice as much 02 per kilogram of
body mass compared to humans).
In comparison, human bronchi and bronchioles collapse under great pressure and
cannot store excess nitrogen.
 High concentrations of myoglobin
allow them to store 25% of 02 in
muscle compared to 13% in humans.
The pie charts below show that the distribution of oxygen d iffers remarkably
between humans and Weddell seals. Looking at the charts, describe the relationship
between the blood. Try to explain the percentage of oxygen found in the lungs of
humans and Weddell seal.
 Their huge spleen can store 25 litres
of blood.
Muscle
13%
Lungs
38%
4
Muscle
25%
Blood
51%
Lungs
5%
ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
© Learning and Teaching Scotland 2011
Blood
70%
 They store 5% of 02 in relatively
small lungs and 70% in blood (twice
as much blood per kilogram of body
mass compared to humans).
Way Down Low – Resource Sheet 2, Part 2
Cetaceans
Sperm whales have two to
three times more blood per
kilogram of body weight
compared to humans and
carry high concentrations
of myoglobin in muscle.
After a dive sperm whales
rapidly replenish their O 2
with the aid of a
particularly powerful
heart and circulatory
system with large
networks of capillaries.
How does an
animal that can
dive so deep
avoid the bends?
Cetaceans (which include the marine mammals commonly known as whales,
dolphins and porpoises) are the mammals best adapted to aquatic life. Their
bodies are fusiform (spindle-shaped). The forelimbs are modified into flippers.
The tiny hindlimbs are vestigial; they do not attach to the backbone and are
hidden within the body. The tail has horizontal flukes. Cetaceans are nearly
hairless and are insulated from the cooler water they inhabit by a thick layer of
blubber. Some species are noted for their high intelligence.
The sperm whale
Sperm whales are the deepest diving whales. Although they live at the sur face
they dive to hunt giant squid, which are bottom dwellers (live at the bottom of
the sea). They have been known to dive as deeply as 3200 metres (10,500 feet),
but average dives are about 1200 metres (4000 feet). Sperm whales can hold their
breath for about an hour.
ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
© Learning and Teaching Scotland 2011
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Student Information (continued)
Here is some information
comparing diving depth
and time under water for
different vertebrate.
You may wish to refer to
this when comparing
organisms’ diving depths.
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ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
© Learning and Teaching Scotland 2011
Student Information
What to do...
You have been asked by your magazine editor to write an article using the information in the resource sheets. Your article must
be at a level suitable for other students at school or university level. This means explaining and understanding not only the
adaptations of organisms but also any underlying science behind your findings and research.
Collect the resource sheets (1, 2 and 3) and copies of journal articles (‘Diving adaptations of the Weddell seal’, a paper
submitted to Barologia, the journal of the South African Society for underwater science, ‘The challenges of diving to depth’
and ‘The physiology and ecology of whales and porpoises ’). The links to these articles are given at the bottom of this
information sheet. You can also look at this link if you are researching the adaptation of humans living at high altitudes,
http://www.summitpost.org/high-altitude-what-happens-to-the-human-body-in-the-death-zone/371306, and any other articles
your teacher supplies. Look at several different magazines/newspapers and as a group decide which format you will use to
display your information.
Follow the steps below.
Step 1: Determine if you are going to research organisms found to live in one particular niche ‘up high’ or ‘down low’, or make
a comparison of organisms living in both environments.
Step 2: Identify at least three areas of adaptation to focus on (eg blood, heart rate, pressure, physiological, behavioural,
anatomical adaptations). Develop appropriate questions (eg what physiological adaptations do these organisms have which
allow them to survive in extreme habitats). Get involved in interactive discussion about the adaptations and decide who will
research specific adaptations in your group.
Step 3: Once you have identified how organisms are able to survive in the extremes you can c ompare and contrast the
adaptations of two or more vertebrates (you may use given resources, ie printed journal/magazine articles, or research your own
choice of organisms, depending on the resources available). For example, you may wish to compare human adaptations that
ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
© Learning and Teaching Scotland 2011
7
Student Information (continued)
allow them to survive in ‘up high’ or ‘down low’ environments, or concentrate solely on organism adaptations that allow them
to occupy a particular extreme habitat.
Step 4: Each member of the group is responsible for their own research. Once sufficient research and evidence ha ve been
gathered it is time to collate and organise your research as a group. A plan must be made and an example arti cle template
collected. Each member of the group then writes their own article. You must all proof-read each other’s work before handing it
back to the editor.
Step 5: Review, refine and improve. You will collect and complete a review form to assess the other articles produced by the
class. Your teacher will collect feedback from you and use this to look at your improvements and recommendation s for other
students’ articles.
Step 6: Your teacher will provide feedback and assessment of learning . You will be given the opportunity for self-assessment
(using the extreme news assessment sheet) for your own document and use this plus the class review forms to improve your
article before it is sent to the publishers.
Links to journal articles
1.
2.
3.
4.
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Diving adaptations of the Weddell seal
http://www.joergenbraad.dk/DykningRessourcer/DykningRessourcerum10/LinkedDocuments/DivingWeddellSeal.pdf
A paper submitted to Barologia, the journal of the South African Society for underwater science
http://www.rubicon-foundation.org/dspace/bitstream/123456789/6137/1/S PUMS_V7N2_3.pdf
The challenges of diving to depth
http://faculty.smu.edu/bjacobs/biol3307/session1/challengesdepth.pdf
The physiology and ecology of whales and porpoises
http://140.122.143.143/snake/%E7%94%9F%E7%90%86%E7%94%9F%E6%85%8B/%E7%94%9F%E7%90%86%E7%94
%9F%E6%85%8B%E5%AD%B8%E8%AC%9B%E7%BE%A9%E9%9B%BB%E5%AD%90%E6%AA%94/14.%20the%20
physiological%20ecology%20of%20whales%20and%20porpoises.pdf
ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
© Learning and Teaching Scotland 2011
Example Article Template
Title
Picture
Picture
ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
© Learning and Teaching Scotland 2011
9
Example Article Template
Four areas
identified then
an explanation
in each of the
four boxes
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ANIMAL ADAPTATIONS TO SURVIVE LOW OXYGEN NICHES (H, BIOLOGY)
© Learning and Teaching Scotland 2011