Biology 2.6: Describe
diversity in the structure
and function of animals
Chapter 21 in Textbook (p210)
Achievement Standard 90462
3 Credits
ANIMAL Diversity 1
Learning Intention:
Identify 3 animals with different types of gas exchange systems.
Define gas exchange, breathing and cellular respiration and explain how they are
linked
SUCCESS CRITERIA:
Can Identify 3 animals with different types of gas exchange systems.
Can Define gas exchange, breathing and cellular respiration and explain how they
are linked
What is Diversity?
http://www.youtube.com/watch?v=jLuK-EBkcww
•
•
•
•
Diversity:
[dih-vur-si-tee]
noun, plural
1. the state or
fact of being
diverse;
difference;
unlikeness.
• 2. variety;
3 animals
• For each of the animals pictured below, describe their
habitat and their structural, physical and behavioral features
• Is there a relationship between their features / adaptations
and their habitat? Discuss.
http://www.youtube.com/watch?v=7798h1s
iNO8
Terminology
• 73774728466
• 427 39242643
• 273284464
Term
My Definition
Biological
Definition
The difference
between the two
Gas Exchange
• “The movement of gases across a membrane”
Why do we need
to carry out gas
exchange?
Figure 10.8A
Breathing
Animation
ANIMAL Diversity 2
Learning Intention:
Identify the need for a gas exchange system in multicellular animals
Describe the characteristics of an efficient gas exchange system
SUCCESS CRITERIA:
States the need for a gas exchange system
States the characteristics of an efficient gas exchange sys
GAS EXCHANGE IN ANIMALS
We will be studying the diversity of adaptations
for this process in THREE animal groups:
Fish
Mammals
Insects
GAS EXCHANGE SURFACES
Gases move by diffusion.
Diffusion is greater when:
• the surface area is large
• the distance travelled is small
• the concentration gradient is high
Gas exchange also requires a moist surface
• O2 and CO2 must be dissolved in water to
diffuse across a membrane
GAS EXCHANGE SURFACES
To maximise diffusion, an efficient gas exchange
surface will…
1. have a large surface area
2. provide a small distance for gases to diffuse
across
3. be moist
4. Maintain a favourable concentration gradient
for the diffusion of both gases.
STRUCTURE OF THE GAS
EXCHANGE SURFACE
Depends on:
• the size of the organism
• where it lives – water or land
• the metabolic demands of the
organism – high, moderate or low
DIVERSITY IS REQUIRED!!!!
Need for a gas exchange system in multicellular
animals
PROBLEM
• the distance a gas can diffuse is only millimeters
• This means single celled and very small organisms can easily
exchange gases over their membranes as they have a large
surface area compared to their volume
• But why cant multicellular organisms?
As multi-cellular organisms get larger, more and more cells will
not be in direct contact with the air or will not be near enough to
the surface to receive oxygen and expel carbon dioxide through
direct diffusion. They have a low surface area: volume ratio
They therefore need a gas exchange system
Conclusions:
• As an organism becomes larger, their volume
increases at a faster rate than their surface area.
Problems?
Only inactive organisms
could be supported
• Solutions?
Flattened shape OR
surfaces
It would take too
long to reach the
middle of the
organism
Specialised exchange
multicellular animals need a gas exchange system
An exception:
• Many multicellular animals are small enough that
they don't require a specialized gas exchange
system
• Flatworms (phylum Platyhelminthes) have
adaptations that eliminate the need for a complex
respiratory (and circulatory) system.
• Platyhelminthes are flattened—
"flatworms." This flattening makes
them very thin and gives them a
large ratio of surface area to
volume.
• The flatworm's respiratory surface
area is large enough to service its
relatively low volume.
Task
1. Do WB p 191, 192
2. Exam Q:
•
Multicellular animals are large and have made
certain adaptations to ensure their
oxygen
requirements are met. Explain why they have made
these adaptations
and the common features of
the adaptations
ANIMAL Diversity 3
Learning Intention:
Describe how a moist, thin, large surface area within a gas
exchange system is achieved in Insects
SUCCESS CRITERIA:
Label parts of an insects anatomy
Explain gas exchange in insects
Gas Exchange in Insects
• Take your photocopy, and make notes
as we move through the process of gas
exchange for insects
• The respiratory system of insects (and many other
arthropods) is separate from the circulatory
system. It is a complex network of tubes (called a
tracheal system) that delivers oxygen-containing air
to every cell of the body.
• Air enters the insect's body through valve-like
openings in the exoskeleton.
• These openings (called spiracles) are located along
the thorax and abdomen of most insects -- usually
one pair of spiracles per body segment.
• Air flow is regulated by small muscles within each
spiracle
• After passing through a spiracle, air enters a
longitudinal tracheal trunk
• It diffuses throughout a branching network of
tracheal tubes that subdivide into smaller and
smaller diameters and reaches every part of the
body.
• At the end of each tracheal branch, a special cell
(the tracheole) provides a thin, moist surface for the
exchange of gasses
• Oxygen is dissolved in liquid at the tracheole and
then diffuses into the cytoplasm of an adjacent cell.
• At the same time, carbon dioxide diffuses out of
the cell and, eventually, out of the body through the
tracheal system.
Tracheoles
Spiracle
Trachea
Task
• WB page 196
ANIMAL Diversity 4
Learning Intention:
Describe how a moist, thin, large surface area within a gas
exchange system is achieved in mammals
SUCCESS CRITERIA:
Label parts of a mammal anatomy
Explain gas exchange in mammals
DO NOW:
Draw an insect and label parts
of its respiratory system
Human Respiratory System
Figure 10.1
Four Respiration Processes




Breathing (ventilation): air in to and out of
lungs. 2 parts – Inspiration (breathing in)
and Expiration (breathing out)
External respiration: gas exchange
between air and blood
Internal respiration: gas exchange
between blood and tissues
Cellular respiration: oxygen use to produce
ATP, carbon dioxide as waste
Components of the Lower
Respiratory Tract
Figure 10.3
MAMMAL LUNGS: BREATHING
Two lungs ventilated by movement
of diaphragm and ribs
MAMMAL LUNGS: STRUCTURE
Rubber cast of human lungs
MAMMAL LUNGS: STRUCTURE
System of tubes (held open by rings of
cartilage) allow air to flow in and out of lungs
• Air enters via trachea
(windpipe)
• Trachea branches into
two bronchi (one
bronchus to each lung)
• Bronchi branch into
bronchioles
MAMMAL LUNGS: STRUCTURE
Many alveoli at the end of the bronchioles
• walls made of flat cells; only one cell thick
• each alveolus lined with moisture
• surrounded by capillary network carrying blood
GAS EXCHANGE IN MAMMALS
Gas exchange
animation
ENHANCING THE EFFICIENCY OF
MAMMAL LUNGS
Large surface area
• many tiny alveoli
• area as big as a tennis court in humans!
Short distance for diffusion
• alveoli and capillary walls only one cell thick
• capillaries pressed against alveoli
Moist
• wet lining of alveolus
• system internal to reduce water loss by evaporation
Maintaining a concentration gradient
• air (with depleted O2 and excess CO2) is exhaled  replaced with fresh
inhaled air
• blood (having lost CO2 and been enriched with O2) returns to heart to
get pumped around body
Task
• WB p 197-199
• http://bcs.whfreeman.com/thelifewire/conte
nt/chp48/4802002.html
ANIMAL Diversity 5
Learning Intention:
Describe how a moist, thin, large surface area within a gas
exchange system is achieved in fish
SUCCESS CRITERIA:
Label parts of a fish anatomy
Explain gas exchange in fish
DO NOW:
Draw a mammals respiratory
Structures (include lungs AND
close up of alveoli). Use red and blue
to show Blood oxygenation
http://newswatch.nationalgeographic
.com/2011/06/16/weird-wildspongebob-mushroom-named/
Blood
https://www.msu.edu/~kalinkat/professionalp
ages/TechMatrixMaterials/documentarybloo
dmisconceptions.htm
Hodgson: incorrect
Michigan State Uni: correct
Anatomy External
GETTING OXYGEN FROM WATER:
FISH GILLS
• Each gill made
of four bony
gill arches.
• Gill arches
lined with
hundreds of
gill filaments
that are very
thin and flat.
GETTING OXYGEN FROM WATER:
FISH GILLS
• Gill filaments are
have folds called
lamellae that contain
a network of
capillaries.
• Blood flows through
the blood capillaries
in the opposite
direction to the flow
of water.
Each gill arch has many filaments
Each filament has many lamellae
RADAR TIME
• Using your Radar, colour in how
developed your knowledge is of the
anatomy of the fish gill.
• If you colour:
– 1/3: Trace and label the structure from TB
p212 on a new piece of paper
– 2/3 : Do p193 in WB
– 3/3: put your hand up
OSMOSIS INTERNAL
You have 10 min.
? = more info required
X = incorrect
* = does not make sense
CV = control variable identified
General comment:
Make sure you identify the correct Independent,
Dependent and Control variables before moving
on
ANIMAL Diversity 6
Learning Intention:
Describe how a moist, thin, large surface area within a gas
exchange system is achieved in fish
SUCCESS CRITERIA:
Explain gas exchange in fish
DO NOW:
Draw a mammals respiratory
Structures (include lungs AND
close up of alveoli). Use red and blue
to show Blood oxygenation
GETTING OXYGEN FROM WATER:
FISH GILLS
• Gills covered by an
operculum (flap)
• Fish ventilates gills by
alternately opening and
closing mouth and operculum
 water flows into mouth
 over the gills
 out under the operculum
• Water difficult to ventilate
 gills near surface of body
WATER AS A
GAS EXCHANGE MEDIUM
No problem in keeping the cell membranes
of the gas exchange surface moist
BUT
O2 concentrations in water are low,
especially in warmer and/or saltier water
SO
the gas exchange system must be very
efficient to get enough oxygen for respiration
ENHANCING THE EFFICIENCY
OF FISH GILLS
• Gills have a very large surface area:
four arches with flat filaments with lamellae
folds
• Gills are thin-walled and in close contact
with water: short distance for diffusion
• Gills have a very high blood supply to
bring CO2 and carry away O2  dark red
colour
• Gills are moist: fish live in water!
ENHANCING THE EFFICIENCY
OF FISH GILLS
Fresh water flows over gills in one direction.
COUNTER-CURRENT FLOW: water and blood in
the gills flow in opposite directions
 maintains a favourable concentration gradient
for diffusion of both gases
Concurrent
flow animation
Countercurrent
flow animation
CONCURRENT FLOW
COUNTER-CURRENT FLOW
Task
Radar
• 1/3 – come sit in front bench
• 2/3- continue with TB p194 as a group,
utilizing answer booklet
• 3/3 – worksheet
ANIMAL Diversity 7 and 8
Learning Intention:
Compare and contrast how efficient gas exchange is maintained in 3
animal groups
SUCCESS CRITERIA:
Explain how efficient gas exchange is maintained in 3 animal groups
DO NOW:
Draw a fish’s respiratory
Structures.
Use red and blue
to show Blood oxygenation
Insects
Mammals
Fish
Explain how the
concentration
gradient is maintained
Explain how the
diffusion distance is
minimised
Explain how the gas
exchange surface is
kept moist
Explain how a large
gas exchange surface
area is provided
Remember – annotated diagrams tell 1000 words!
You have the double period to complete this to Excellence standard.
Use your notes, books, and the PWP is available to use
GETTING OXYGEN FROM AIR:
MAMMALS, BIRDS & INSECTS
As a gas exchange medium, air has many
advantages over water:
• Air has a much higher oxygen
concentration than water
• Diffusion occurs more quickly so less
ventilation of the surface is needed
• Less energy is needed to move air
through the respiratory system than water
GETTING OXYGEN FROM AIR:
MAMMALS, BIRDS & INSECTS
BUT
as the gas exchange surface must be
moist, in terrestrial animals water
is continuously lost from the gas
exchange surface by evaporation
SO
the gas exchange surface is folded
into the body to reduce water loss.
WARM-BLOODED ANIMALS
Warmth speeds up body’s reactions
 enables faster movement etc
BUT
increases evaporation of water from lungs
AND
increases demand for energy to stay warm
SO
higher demand for gas exchange to provide O2
for and remove CO2 from respiration
ANIMAL Diversity 9
Essay scaffolding
ANIMAL Diversity 10
Learning Intention:
Compare and contrast colours of gas exchange surfaces
SUCCESS CRITERIA:
Explain similarities and differences in colours of gas exchange
surfaces
DO NOW:
• Draw fish, mammal and insect
respiratory structures.
• Label and use red/blue to
show oxygentaed and deoxygenated blood
Compare and contrast
• Colour. Why?
Unit Standard 8925
• Wed
– P6 – Lung Dissection (40min) (element 1)
• Thursday
– P3 – Gill dissection (element 1)
– P4 – Write-up Element 1 and Element 2
Element 1 – Dissections
- Task 1 - drawing and labeling structures
- Task 2 - Write-up: 3 questions based on the structures.
Element 2 – Unit Standard test
- Task 1: how animal group achieves efficient gas
exchange
- Task 2: How gas exchange systems are related to
the animals way of life
How many filaments?
• You will have to work out how many
filaments a fish has in your Unit Standard
How will you do it?
Step 1: count the
number of filaments in a
cm piece of gill arch
Step 2: ….