Biology 2.6

Animal Diversity

Biology 2.3

Animal

Adaptations

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 salamander-like)

• Used in research b/c of their ability to regenerate limbs

Neoteny in humans: http://en.wikipedia.org/wiki/Neoteny#Neotenous_traits_in_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 pressure they can withstand without collapsing. This may be one reason why insects are relatively small. The increased weight of the tissues of an animal the size of a rabbit, for example, would crush tracheal tubes filled only with air.

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.

How is this different from ventilation in mammals? How does it compare to ventilation in birds? Explain.

Liquid seal Liquid seal

(air) (air)

Rubber diaphragm

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?

1. This is wrong. This book says that vertebrates use Hb & arthropods use hemocyanin (Cu-based) as their respiratory pigment.

2. Hmm… Zee insect obviouzly ‘as trrouble sustaining aerrobic rezpiracion in zee wadairr.

3. This insect must be an endotherm with a high BMR & high O2 demand.

4. I think maybe the insect stores O2 in this way.

Tracheal System in Insects

Each cell has a nearly direct meansof 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

(May serve as storage reserve)

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.

Under a paddle crab carapacehorseshoe crab blood horseshoe crab

• http://www.youtube.com/watch?v=gkui_DWJGcc

• http://www.youtube.com/watch?v=Fh4MhAmdDk0

Fish

Water(as a gas exchange medium)

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

Pros• O2 already dissolved• Water provides

buoyancy (keeps gill filaments separated…SA!)

• Environment keeps gas exchange surface moist– More energy needed to

ventilate it

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 • Cancer 7 times http://www.facethefacts.org.nz/

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 27.09.10Dave 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 ofbreathing?

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.

TasksA) Calculate the percentage of total lung capacity that

can be used for gas exchangeB) Find your -

• Tidal Volume: ________ L • Vital Capacity: ________ L• Total capacity: ________ 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 - AdvantagesRespiratory surface stays moist…O2 already dissolved

Water – DisadvantagesO2 levels lowerWater viscous, more energy to ventilate…Warmer water = less O2Saltier water = less O2

Habitats

Air - AdvantagesHigher 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 – DisadvantagesRespiratory surface dries outDust, pathogens…

Air as a Gas Exchange MediumPros• 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, 2007You are advised to spend 35 minutes answering the questions in this booklet.

QUESTION ONEFor 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 TWODiscuss why diversity exists across your chosen animal groups, in order for them to survive and be successful in their habitats.

Bio 2.6 Paper - 2008QUESTION 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