Transcript Biology 2.6

Biology 2.3
Animal Diversity
Animal Adaptations
Biology 2.6
Gas Exchange
Fish, Insects, Mammal
Bio 2.3
Information Sources:
• Your own notes
• Biozone 2012, pg49-59
• LifeScience, pg140-149
• Patterns of Life, pg211-215
• Life Study, pg 213-216
External Gills - Axolotl
 "transformed“ axolotl
*Axolotls
• Fail to metamorphosise and adults are gilled
and aquatic (neoteny = juv features in
adults)
– why? Lack thyroid gland, injections of iodine
cause metamorphosis (become salamanderlike)
• Used in research b/c of their ability to
regenerate limbs
Neoteny in humans:
http://en.wikipedia.org/wiki/Neoteny#Neotenous_traits_i
n_humans
Insect Gas Exchange
• Insect Tracheoles
• Insect tracheoles
• This photomicrograph show how the walls
of the tracheal tubes are stiffened with
bands of chitin. Even so, there is a limit to
The abdomen in large, active insects like grasshoppers, is used like a bellows to
force air out of tracheae with contraction of skeletal muscles.
What happens when these muscles relax?
The experiment illustrated (first performed by the insect physiologist Gottfried
Fraenkel) shows that there is a one-way flow of air through the grasshopper. The
liquid seals at either end of the tubing move to the right as air enters the first four
pairs of spiracles in the thorax and is discharged through the last six pairs in the
abdomen.
Rubber diaphragm
Liquid seal
Liquid seal
(air)
(air)
How is this different from ventilation in mammals? How does it compare to
ventilation in birds? Explain.
1. This is wrong. This
book says that
vertebrates use Hb &
arthropods use
hemocyanin (Cubased) as their
respiratory pigment.
3. This
insect must
be an
endotherm
with a high
BMR & high
O2 demand.
2. Hmm… Zee
insect obviouzly ‘as
trrouble sustaining
aerrobic rezpiracion
in zee wadairr.
4. I think
maybe the
insect
stores O2
in this
way.
The aquatic air-breathing insect Notonecta has tracheal cells
(cells lining the respiratory passages) that contain
hemoglobin. What advantage would this metallo-protein
serve in a diving, air-breathing insect?
Tracheal System in Insects
(May serve as
storage reserve)
Each cell has a nearly direct means
of gas exchange via the tracheal system
(2-4 spiracles on the thorax, 6-8 on abdomen).
What is the advantage of such a
system for a small, fast animal?
Do insects have respiratory pigments in
their hemolymph? Significance?
p. 984
Hameocyanin
• What? A respiratory pigment based on the copper
atom
• Chemistry: Oxygenation causes a colour change
between the colorless Cu(I) deoxygenated form and
the blue Cu(II) oxygenated form.
• Which animals? Molluscs, some arthropods
• How: Haemocyanin floats free in the blood not in cells
like with haemoglobin.
horseshoe crab blood
horseshoe crab
Under a paddle crab carapa
• http://www.youtube.com/watch?v=gkui_D
WJGcc
• http://www.youtube.com/watch?v=Fh4Mh
AmdDk0
Fish
Water
(as a gas exchange medium)
Pros
• O2 already dissolved
• Water provides
buoyancy (keeps gill
filaments
separated…SA!)
• Environment keeps gas
exchange surface moist
– More energy needed to
ventilate it
Cons
• O2 levels low (1-3%)
– Very low in warm water
– Very low in salty water
• Water is dense
– More energy needed to ventilate
it
• Parasites, pathogens, debris
in water
– Gill rakers
• Osmotic damage
– Water diffuses into cells until
they burst
Parallel Flow
Counter Current Flow
Mammals
Mammalian Respiratory System
Mechanics of Respiration:
negative pressure breathing
How do the serous membranes that cover the surfaces of the lungs
and line the thoracic cavity facilitate breathing?
Pneumothorax
(= collapsed lung)
• Chest injury or internal leakage causes air to be
pulled into lungs from outside of body – lung
collapses.
Tracheostomy
• a surgical operation that creates an
opening into the trachea with a tube
inserted to provide a passage for air;
performed when the pharynx is obstructed
by edema or cancer or other causes
Smoking & the Lungs…
•
•
•
•
Started smoking casually at age 18
Two-pack-a-day addiction, 22 years
Permanent tracheotomy
http://www.facethefacts.org.nz/
Cancer 7 times
Rescue Breathing
• Works as exhaled air still ~15% O2
– Survive in an air sealed room…
– Rebreathing…
– Deep diving, hold breath records…
• Rescue breathing protocols always
changing (based on research)
– 1st: flap arms
– Recent research: cpr alone
Free-diving
• One of various aquatic activities that
share the practice of breath-hold
underwater diving.
– Pool disciplines
• Static Apnea is timed breath holding
and is usually attempted in a pool (men:
11 min 35 sec, women: 8 min 23 sec)
• Dynamic Apnea With Fins. Distance
swum underwater in pool, bi-fin or mono
fin (men: 265No-Limits Apnea m (nzer
Dave Mullins in Sept 2010, women:
225m)
• Dynamic Apnea Without Fins.
Distance swum underwater, no fins
(men: 213m (NZer Dave Mullins)
– Depth disciplines
• Constant Weight Apnea. No fins, no
weights, follow rope only (men: 95m)
• No-Limits Apnea. Any method, most
use weighted sled (down), inflatable bag
(up) (Men: 214m) + other “events”
Apnea = cessation of
breathing
Clips
• Dave 265M Dynamic Apnea with fin World
Record 25 Sept 2010.
– http://www.youtube.com/watch?v=0WFDWYNs4A
c&feature=related
• Freediving World Record no fins 88m (288ft)
– http://www.youtube.com/watch?v=vF4PN8-2YSk
• The Ultimate Dive. The deepest dive in
history: -209.6 m
– http://www.youtube.com/watch?v=0J8GVGkw7Yc
ANOTHER WORLD RECORD FOR DAVE MULLINS
27.09.10
Dave Mullins has once again set a new World Record In Dynamic No fins,
extending the previous world record that he held by 5m at Porirua Aquatic
Centre today, taking it to 218m.
He had jointly held the previous best mark of 213m with German Tom Sietas,
although Mullins’ unofficial personal best and New Zealand record in the
discipline is 232m.
On Saturday, the 2m tall New Zealander broke Frenchman Fred Sessa’s record
for the dynamic apnea, with fins discipline, swimming 265m underwater without
taking a breath at the Naenae Olympic Pool.
Mullins took advantage of shorter length 25m pool in Porirua today, the extra
turns meaning he could push off more without fins.
“I didn’t swim to my potential, I was a bit tired today after Saturday’s effort but
I’m glad to have achieved what we set out to do,” Mullins told NZPA.
“I probably could have pushed it a bit more today but if I had tried to kick on and
things had gone bad, I could have been disqualified and I would have kicked
myself. I’m happy to have just broken the record.” http://aidanz.co.nz/news/
Physiology of Freediving
• The human body has several adaptations under diving
conditions, which stem from the mammalian diving reflex.
These adaptations enable the human body to endure depth and
lack of oxygen far beyond what would be possible without the
reflex.
• The adaptations made by the human body while underwater
and at high pressure include:
– Reflex bradycardia: Drop in heart pulse rate.
– Vasoconstriction: Blood vessels shrink. Blood stream directed away
from limbs for the benefit of heart, lungs and brain.
– Splenic Contraction Releasing red blood cells carrying oxygen.
– Blood shift: Blood plasma fills up blood vessels in the lung and reduces
residual volume. Without this adaptation, the human lung would shrink
and wrap into its walls, causing permanent damage, at depths greater
than 30 meters
Regulation of
Breathing
High levels of CO2 (and low
pH due to acidity of dissolved
CO2) in blood relayed to
breathing control centre 
triggers diaphragm and
intercostal muscles to contract.
How does hyperventilation
affect the control centres of
breathing?
Should you hyperventilate
just before your underwater
swim test? Why or why not?
Is 100% O2 a good idea for
hospital patients who need
assistance breathing?
monitor
CO2 (& pH)
Transport of Carbon
Dioxide#1
70% of CO2 is carried as
bicarbonate ions in RBC
23% of CO2 is carried
joined to haemoglobin
7% of CO2 is carried
dissolved in plasma
(exact percentages vary
between venous and
arterial blood)
Transport
of Carbon
Dioxide #2
Carbonic anhydrase catalyzes the conversion of
carbon dioxide to bicarbonate reaction in both
directions:
CO2 + H2O → H2CO3 → H+ + HCO−3
Explain how this is possible…(think about conc
gradients in lungs and cells)
What “drives” the diffusion of bicarbonate out
of RBCs?
Is there a “potential” problem associated with
the loss of HCO3- ?
Aspect
Litres
Description
Tidal air volume
0.5
Air exchanged during normal breathing
Inspiratory reserve
volume
3.0
Air breathed in during a deep breath (over & above the tidal
air volume)
Expiratory reserve
volume
1.0
Extra air forced out after normal exhalation
Vital capacity*
4.5
Total air expired after a maximum inspiration (tidal +
inspiratory + expiratory volumes)
Residual volume
1.5
Air left in lungs even after maximum expiration
Total Capacity
6.0
Vital capacity + Residual Volume
* In an average man this is 4-5 litres. In a fit athlete it may exceed 6 litres.
Of the 0.5 litres of tidal air only 0.35 litres gets into the part of the lungs where gas
exchange is possible. The rest remains in the trachea and bronchial tubes,
collectively known as dead space.
Tasks
A) Calculate the percentage of total lung capacity that
can be used for gas exchange
B) Find your •
•
•
Tidal Volume:
Vital Capacity:
Total capacity:
________ L
________ L
________ L
C) Find your volume of air breathed in 1 minute
Number of breaths /
min (rate)
Volume of one breath
(tidal)
Volume of air breathed
(rate x tidal)
Air vs Water, Lifestyles…
Habitats
Water - Advantages
Respiratory surface
stays moist…
O2 already dissolved
Water – Disadvantages
O2 levels lower
Water viscous, more
energy to ventilate…
Warmer water = less O2
Saltier water = less O2
Habitats
Air - Advantages
Higher O2 levels
- less ventilation, less
energy needed…
- More O2, more resp,
more ATP…
Less viscous
- More ventilation…
O2 diffuses faster in air
(x1,000,000)
Air – Disadvantages
Respiratory surface
dries out
Dust, pathogens…
Air as a Gas Exchange Medium
Pros
• High in O2
– 20x more than water at
same temp
• Diffusion of gases fast
– (more rapid than in H2O
• Not viscous
– Fast movement of air
– Little energy used (1/10 of
energy to ventilate water)
Cons
• Dry
– Gas exchange surface
dries out
• Carries dust, pathogens
Internal Gas Exchange
Pros
• Surface protected
from:
– Drying out
– Pathogens
– Parasites
Cons
• Must use energy to
ventilate
• Longer pathway for
air/water flow
• Must dissolve O2 into
moisture on gas
exchange surface
Past Exam Papers
Bio 2.6 Level 2 Biology, 2007
You are advised to spend 35 minutes answering the questions in this booklet.
QUESTION ONE
For each of the animal groups you have chosen, describe the structures
involved in the biological process you have named. In each case, describe how
these structures function, and explain how they allow each group to survive in
their habitat. Diagrams may be used in your response, but they must be clearly
labelled.
Animal group one…
QUESTION TWO
Discuss why diversity exists across your chosen animal groups, in order for
them to survive and be successful in their habitats.
Bio 2.6 Paper - 2008
QUESTION ONE
(This question should be answered for each of the animal groups you
have chosen, but only for the biological process you have studied)
Describe the structures involved, how they work, and explain how they
allow each group to survive in their environment. Diagrams may be
used in your response, but they must be clearly labelled.
• Animal group one:
• Animal group two:
• Animal group two:
QUESTION TWO
• Discuss the reasons for diversity in the structure and function of
your chosen animal groups, in relation to your chosen biological
process, and the environments they live in. (You should compare
and contrast between at least TWO of your chosen animal groups.)
2008 - QUESTION ONE
• Describe the structures involved, how they work, and explain
how they allow each group to survive in their environment.
2007 - QUESTION ONE
• For each of the animal groups you have chosen, describe the
structures involved in the biological process you have named.
In each case, describe how these structures function, and
explain how they allow each group to survive in their habitat.
2006 - QUESTION ONE
• You are required to describe and give reasons for how your
chosen biological process is carried out by your three animal
groups.
2005 - QUESTION ONE
• Compare the structure and function of THREE animal groups
for the biological process
2008 - QUESTION TWO
• Discuss the reasons for diversity in the structure and function
of your chosen animal groups, in relation to your chosen
biological process, and the environments they live in.
2007 - QUESTION TWO
• Discuss why diversity exists across your chosen animal
groups, in order for them to survive and be successful in their
habitats
2006 - QUESTION TWO
• Discuss the reasons for the diversity in the structure and
function for the biological process in your three animal groups
2005 - QUESTION TWO
• With respect to the environment of each animal group,
evaluate why there is diversity in the structure and function for
your named biological process.
2007
For Insects…
2007 - QUESTION ONE
• For each of the animal groups you have
chosen, describe the structures involved in
the biological process you have named. In
each case, describe how these structures
function, and explain how they allow each
group to survive in their habitat.
2007 - QUESTION TWO
• Discuss why diversity exists across your
chosen animal groups, in order for them to
survive and be successful in their habitats
2010