This document discusses animal form and function at different levels of biological organization. It covers topics like anatomy, physiology, bioenergetics, homeostasis, thermoregulation, and adaptations like torpor and acclimatization. The key points are: 1) Animal form is shaped by natural selection to fit its function and environment over many generations. Its structure at different levels from cells to organ systems allows it to interact with its environment. 2) Bioenergetics examines how animals obtain and use energy from food. Having the right surface area to volume ratio and internal structures allows efficient exchange of materials in multicellular organisms. 3) Homeostasis and thermoregulation allow animals to maintain stable internal conditions

1. Basic Fundamentals:
Animal Form and Function
1
What you will learn:
Animal form and function, levels of organization, Bioenergetics, homeostasis,
mechanisms of homeostasis, regulation, thermoregulation (body temp),
endotherms and ectotherms, 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: Mechanisms by which organisms obtain processes and use
their energy resources

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
Natural selection cannot break rules of physics which limits evolution of an
organisms form
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
Animal body plan tries to submerge all cells in aqueous medium to maintain
fluid integrity of PM
Diffusion across PM
Surface to volume ratio in protists (unicellular)
Multicellular organisms: different cells have different diffusion pattern
Amoeba
Hydra
a) Single cell
Flat body
Tapeworm (Taenia)
Large surface area in
contact with
environment and not
much complexity

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
Small size allows large surface area-to-volume ratio which
allows rapid uptake and intracellular distribution of
nutrients and excretion of wastes.
At low surface area-to-volume ratios
• the diffusion of nutrients and waste products
across the cell membrane limits the rate at which
metabolism can occur,
• making the cell less evolutionarily fit.
S/V of a whale is 100-1000X smaller than water flea (Daphnia)
But inside whale each cell must get access to same O2, nutrients and
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
ORGANS AND ORGAN SYSTEM: different tissues organized into organs.
Organ systems carry major bodily functions. All organs of a system must be
coordinated for an animal to survive
Eg.nutrients absorbed by digestive system is distributed by circulatory system further
dependent on respiratory system.
Same applies to single and muticellular animals

11. CHEMICAL ENERGY TO SUSTAIN FORM AND FUNCTION
Growth
Repair
Physiology
Regulation
Reproduction
Autotrophs
Heterotrophs
Use of light
or CO2 to
make organic
molecules
Use chemical energy
organic/inorganic) in
food

12. BIOENERGETICS
Flow of energy through an animal: limits growth, behavior, reproduction,
determines how much food is needed. Also explains adaptations.
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 loss OR
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
Body is heated by warmth
generated by metabolism
Allows intense long duration
activity over wide
environmental temperature
High metabolic rate
Body is heated by gained
from external environment.
High cost of heating
Low metabolic rate

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:
Basal metabolic Rate (BMR): metabolic rate of a non growing endotherm at
rest and not experiencing stress
Adult Male: 1600-1800 kcal/day
Adult Female: 1300-1500 kcal/day
Standard Metabolic Rate (SMR): Metabolic rate of resting, fasting, non
stressed ectotherm at a particular temperature
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 can Have 37-38 oC 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
An animal is a
regulator if it
controls internal
change according
to external
fluctuations
Conformer
An animal is a conformer if it allows internal
conditions to vary with certain external
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 - 37oC

22. Positive Feedback: change in some variable that trigger mechanisms to
amplify rather than reverse the change
Negative Feedback: Control mechanism which counteracts change in the
same direction
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
•Process by which animals maintain an internal temperature within tolerable range
•Critical for survival since physio chemical and biochemical changes are sensitive
to body temperature
•Enzyme mediated reactions increase 2-3 fold for 10oC temp incr. till it
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
Circulatory adaptation
Vasodilation:elevated blood flow in skin, increase in diameter of blood
vessels and nerve signals trigger relaxation of muscle walls
Vasoconstriction: reduces blood flow and heat transfer, decrease and
diameter of blood vessels
Counter current heat exchanger
Trapping heat in body core thus reducing loss from extremities (maybe in
contact with ice, 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
Bees and moths are endothermic because of flying (flight muscles) they
generate heat
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. of nerve cells act as thermostat which
respond to changes in body temp to cause
changes that promote heat loss or gain (also
in skin and body parts)

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
Some adaptations………
•Ectotherms have changes in cellular components and their functions like
enzyme variants having same function but operate under different
temperatures.
•Change in FA inmembranes like saturated/unsaturated according to
environmental conditions
•Some produce antifreeze like compounds to protect from subzero temp or
ice formation
•Production of heat shock proteins or stress induced proteins

31. TORPOR Adaptations that save animals to avoid dangerous envtal conditions
Hibernation/winter torpor
Adaptations to cold and food scarcity
Temp may become 1-2oC or below zero
Low MR,less heat production
Live on stored fat
Estivation/Summer torpor
Adaptations to high heat
Inactivity
Slow metabolism
Daily Torpor: adaptations which allow animals to be active during a particular
time of day when metabolism is high and so is energy consumption