1. animal form and function. animal form and function. animal form and function

SLIDE NO.1

1. Basic Fundamentals:
Animal Form and Function
1
Whatyouwilllearn:
Animalformandfunction,levelsoforganization,Bioenergetics,homeostasis,
mechanismsofhomeostasis,regulation,thermoregulation(bodytemp),
endothermsandectotherms,acclimatization,Torpor.

2. Anatomy: study of structure of an organism
Physiology: Study of functions an organism performs
Natural selection
Fits structure to
function by
selection over many
generations in a
population
Bioenergetics:Mechanismsbywhichorganismsobtainprocessesanduse
theirenergyresources

3. BODY PLAN and DESIGN

4. BODY PLAN and DESIGN
Affects how animal interacts with its environment
Pattern of development is programmed by the genome
Result of millions of years of evolution
powered by natural selection
A. Physical Laws
B. Exchange of materials

5. Physical Laws
Naturalselectioncannotbreakrulesofphysicswhichlimitsevolutionofan
organismsform
Why we don’t have unnatural animals like these
Eg:
1.Flying snake
2.Body of a fish has no protrusions to increase drag (all fast swimmers)
3.Convergent evolution: different gps have the same shape
Convergence occurs because natural selection shapes similar adaptations
when diverse organisms face same environmental challenge
A

6. B. Exchange of materials
Animalbodyplantriestosubmergeallcellsinaqueousmediumtomaintain
fluidintegrityofPM
DiffusionacrossPM
Surfacetovolumeratioinprotists(unicellular)
Multicellularorganisms:differentcellshavedifferentdiffusionpattern
Amoeba
Hydra
a) Single cell
Flat body
Tapeworm (Taenia)
Largesurfaceareain
contact with
environmentandnot
muchcomplexity

7. r=1mm
Surface area (4pr2) = 12.6mm2
Volume (4/3pr2) =4.2mm3
Surface
Volume
= 3
r=2mm
Surface area (4pr2) = 50.3mm2
Volume (4/3pr2) =33.5mm3
Surface
Volume
= 1.5

8. Surface to volume ratio
Smallsizeallowslargesurfacearea-to-volumeratiowhich
allowsrapiduptakeandintracellulardistributionof
nutrientsandexcretionofwastes.
Atlowsurfacearea-to-volumeratios
•thediffusionofnutrientsandwasteproducts
acrossthecellmembranelimitstherateatwhich
metabolismcanoccur,
•makingthecelllessevolutionarilyfit.
S/Vofawhaleis100-1000Xsmallerthanwaterflea(Daphnia)
ButinsidewhaleeachcellmustgetaccesstosameO2,nutrientsand
resources
Folding, branching of internal surfaces facilitate exchange

9. “More complex animals have more challenges but have
some benefits also”
1.Special outer covering : protection from predators
2.Large muscles: rapid movement
3.Digestive system: gradual food break down and
controlled release of energy
And many more……
All these maintain a stable internal environment even
when external environment is highly variable.

10. LEVELS OF ORGANISATION OF ANIMAL FORM
TISSUES
ORGANS
ORGAN SYSTEM DIGESTIVE SYSTEM
STOMACH
SMALL INTESTINE
LARGE INTESTINE
All have
different
tissues
TISSUES:group of cells with common structure and function
Epithelial
Connective
Muscle
Nervous
ORGANSANDORGANSYSTEM:differenttissuesorganizedintoorgans.
Organsystemscarrymajorbodilyfunctions.Allorgansofasystemmustbe
coordinatedforananimaltosurvive
Eg.nutrientsabsorbedbydigestivesystemisdistributedbycirculatorysystemfurther
dependentonrespiratorysystem.
Same applies to single and muticellular animals

11. CHEMICAL ENERGY TO SUSTAIN FORM AND FUNCTION
Growth
Repair
Physiology
Regulation
Reproduction
Autotrophs
Heterotrophs
Useoflight
orCO2to
makeorganic
molecules
Usechemicalenergy
organic/inorganic)in
food

12. BIOENERGETICS
Flowofenergythroughananimal:limitsgrowth,behavior,reproduction,
determineshowmuchfoodisneeded.Alsoexplainsadaptations.
1. Energy Sources:
Food ---> ATP ---> Cellular respiration,
fermentation
anaerobic respiration
Organs and organ systems
Animal alive
Production and use of ATP
Generate Heat
Give out heat to maintain balance
Remaining heat used in
1.Biosynthesis
2.Body growth
3.Repair
4.Syn and storage of fat
5.Production of gametes

13. BIOENERGETICS
2. Quantification of Energy:
How much energy from food is necessary to stay alive
walking, swimming, flying ,sitting etc
“Measure rate at which animals use chemical energy and how these rates
change indifferent circumstances”
METABOLIC RATE:
AMOUNT OF ENERGY AN ANIMAL USES IN A UNIT OF TIME
Energy: calories (cal) or kilocal (kcal)
1Kcal = 1000cal
Calorimeter measures rate f heat loss
Can be measured by measuring rate of heat lossOR
Measure amount of O2 consumed or CO2 produced by an animals
cellular respiration
CHO: 4.5-5 kcal/g
Fats: 9kcal/g

14. 3. Bioenergetic Strategy:
BIOENERGETICS
Endothermic Ectothermic
Birds, mammals Fishes,reptiles,amphibians,
invertebrates
Bodyisheatedbywarmth
generatedbymetabolism
Allowsintenselongduration
activity over wide
environmentaltemperature
Highmetabolicrate
Bodyisheatedbygained
fromexternalenvironment.
Highcostofheating
Lowmetabolicrate

16. Factors influencing Metabolic Rate
1.Size of an animal:
Body size 1
amount of energy for
maintenance of body weight
Small animals have high MR
Rate of oxygen delivery to tissues
Hence
High breathing rate
Blood volume (rel. to size)
Heart rate (pulse rate)
∝
∝
∴must eat more food per unit body mass
>
MR
Still unclear many questions unanswered

17. Factors influencing Metabolic Rate
2. Activity and Metabolic Rate:
BasalmetabolicRate(BMR):metabolicrateofanongrowingendothermat
restandnotexperiencingstress
Adult Male: 1600-1800 kcal/day
Adult Female: 1300-1500 kcal/day
StandardMetabolicRate(SMR):Metabolicrateofresting,fasting,non
stressedectothermataparticulartemperature
Activity increases metabolic rate and MR is maximum during physical acitivity
MR ∝
1
Duration pf physical activity
Time also important: diurnal and nocturnal animals with MR active at diff. time

18. Factors influencing Metabolic Rate
Age
Sex
Size
Body and envt temp
Quality and quantity of food
Activity
O2 availability
Hormonal balance
time

19. Homeostasis
Regulation of internal environment for maintaining stable and constant condition
Open and closed systems
Irrespective of external environment and even when conditions are changing
Eg. Hydra cannot but humans canHave 37-38
o
C body temp
Controlled pH of blood (7.4)
Regulate amt of sugar (90mg glu/100ml)
Hormonal balance
“Maintenance of a steady state or internal balance”
Dynamic state,interplay b/w outside (changeable) and inside (non changeable) envt

20. Mechanisms of Homeostasis
Regulation
Conforming
Regulator
Ananimalisa
regulatorifit
controlsinternal
changeaccording
to external
fluctuations
Conformer
Ananimalisaconformerifitallowsinternal
conditionstovarywithcertainexternal
changes.
Functional components: 1. Receptor
2. Control centre
3. Effector
1.Detects change in internal envt
2.Processes information and directs an app. Response by effector
3.Appropriate response to change and gives feedback to control centre

21. Thermostat
CONTROL CENTRE
Thermometer
(RECEPTOR)
Heater
(EFFECTOR)
Set point 20 -37
o
C

22. PositiveFeedback:changeinsomevariablethattriggermechanismsto
amplifyratherthanreversethechange
NegativeFeedback:Controlmechanismwhichcounteractschangeinthe
samedirection
1.Change may be cyclic (menstrual cycle)
2.Change as a reaction to challenge (immune system)
3.Change may be energy expensive
Regulated change maybe due to :

23. THERMOREGULATION
•Processbywhichanimalsmaintainaninternaltemperaturewithintolerablerange
•Criticalforsurvivalsincephysiochemicalandbiochemicalchangesaresensitive
tobodytemperature
•Enzymemediatedreactionsincrease2-3foldfor10
o
Ctempincr.tillit
denatures
Ectotherms Endotherms
Gain heat from envt metabolic heat to regulate body temp
Generate low heat
need to consume more food; dangerous to
more effective strategy for survival survive when food less
Poikilotherms Homeotherms
Animals whose internal body maintain relatively stable internal envt
temp vary widely
Cold blooded warm blooded

24. MODES OF HEAT EXCHANGE
Conduction
Convection
Radiation
Evaporation Insulation:Hair, feathers, fat etc reduces flow of heat b/w
Animal and envt by lowering energy cost of keeping warm
Mammals have fat associated with skin, hair,nails or integumentary ssystem
Epidermis Hypodermis
Dead epithelial cells adipose tissue, fat storing cells
Hair follicle,oil, sweat glands, gives insulation
Muscles, nerves, blood vessels has blood vessels
Marine mammals have BLUBBER to maintain internal core temp of 36-38 but MR
Is same as land mammals

25. MODES OF HEAT EXCHANGE
Circulatoryadaptation
Vasodilation:elevatedbloodflowinskin,increaseindiameterofblood
vesselsandnervesignalstriggerrelaxationofmusclewalls
Vasoconstriction:reducesbloodflowandheattransfer,decreaseand
diameterofbloodvessels
Counter current heat exchanger
Trappingheatinbodycorethusreducinglossfromextremities(maybein
contactwithice,snow,water)
Cooling by evaporative heat loss
Panting, sweating, breathing, saliva on body, mucus, swimming

27. Metabolic heat production
Thermogenesis: Production of heat by mitochondria instead of ATP
Brown fat for rapid heat production
Shivering: generates heat
Beesandmothsareendothermicbecauseofflying(flightmuscles)they
generateheat
Behaviour response
Group behaviour,huddle together, postures to minimise heat loss or gain

28. FEEDBACK MECHANISMS in THERMOREGULATION
Nervous system ------> Hypothalamus Control centre for Homeostasis
Gp.ofnervecellsactasthermostatwhich
respondtochangesinbodytemptocause
changesthatpromoteheatlossorgain(also
inskinandbodyparts)

29. Warm recpetors Cold receptors
Signal HT Signal HT
When temp incr when temp decr
HT

30. ACCLIMATIZATION
Adjustment to a range of temperatures over periods of days or weeks
1.Adjusting amount of insulation (fat or fur)and shedding in summer
2.Vary capacity for metabolic heat production
Constant body temperature in all seasons
Someadaptations………
•Ectothermshavechangesincellularcomponentsandtheirfunctionslike
enzymevariantshavingsamefunctionbutoperateunderdifferent
temperatures.
•ChangeinFAinmembraneslikesaturated/unsaturatedaccordingto
environmentalconditions
•Someproduceantifreezelikecompoundstoprotectfromsubzerotempor
iceformation
•Productionofheatshockproteinsorstressinducedproteins

31. TORPOR Adaptations that save animals to avoid dangerous envtal conditions
Hibernation/winter torpor
Adaptations to cold and food scarcity
Temp may become 1-2
o
C or below zero
Low MR,less heat production
Live on stored fat
Estivation/Summer torpor
Adaptations to high heat
Inactivity
Slow metabolism
DailyTorpor:adaptationswhichallowanimalstobeactiveduringaparticular
timeofdaywhenmetabolismishighandsoisenergyconsumption