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?

• Diversity: • [dih-vur-si-tee]• noun, plural• 1. the state or fact of

being diverse; difference; unlikeness.

• 2. variety; multiformity.

• 3. a point of difference.

http://www.youtube.com/watch?v=jLuK-EBkcww

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=7798h1siNO8

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 ANIMALSWe will be studying the diversity of adaptations for this process in THREE animal groups:

Mammals

Fish

Insects

GAS EXCHANGE SURFACESGases 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 SURFACESTo maximise diffusion, an efficient gas exchange

surface will…1.have a large surface area2.provide a small distance for gases to diffuse

across3.be moist4.Maintain a favourable concentration gradient for

the diffusion of both gases.

Depends on:

• the size of the organism

• where it lives – water or land

• the metabolic demands of the organism – high, moderate or low

STRUCTURE OF THE GAS EXCHANGE SURFACE

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 It would take too could be supported long to reach the

middle of the

organism

• Solutions? Flattened shape OR Specialised exchange surfaces

multicellular animals need a gas exchange 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.

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.

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

Trachea Spiracle

Task

• WB page 196

ANIMAL Diversity 4Learning 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

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

Four Respiration Processes

Components of the Lower Respiratory Tract

Figure 10.3

MAMMAL LUNGS: BREATHINGTwo lungs ventilated by movement

of diaphragm and ribs

MAMMAL LUNGS: STRUCTURE

Rubber cast of human lungs

MAMMAL LUNGS: STRUCTURE

• Air enters via trachea (windpipe)

• Trachea branches into two bronchi (one bronchus to each lung)

• Bronchi branch into bronchioles

System of tubes (held open by rings of cartilage) allow air to flow in and out of lungs

MAMMAL LUNGS: STRUCTUREMany 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

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

ENHANCING THE EFFICIENCY OF MAMMAL LUNGS

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/content/chp48/4802002.html

ANIMAL Diversity 5Learning 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-wild-spongebob-

mushroom-named/

Blood

https://www.msu.edu/~kalinkat/professionalpages/TechMatrixMaterials/documentarybloodmisconceptions.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 6Learning 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

SOthe gas exchange system must be very

efficient to get enough oxygen for respiration

Concentration

gradient problem!

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

Blood gets max

Blood gets max

50% saturation in

50% saturation in

oxygen!oxygen!

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 8Learning 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 FishExplain 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

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.

GETTING OXYGEN FROM AIR: MAMMALS, BIRDS & INSECTS

WARM-BLOODED ANIMALSWarmth 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 10Learning 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: ….