1. Basic Principles of Animal Form and Function
Chapter 40
Basic Principles of Animal Form and Function

2. Diverse Forms, Common Challenges

3. 40.1 Animal Form and function are correlated at all levels of organization
Not a process of conscious invention but the result of a pattern of development programmed by the genome
Physical constraints on size and shape – physical laws that govern strength, diffusion, movement, and heat exchange
Ex) fusiform body shape/convergent evolution
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4. 40.1(con’t) Exchange with the Environment – such as?
- recall lab with agar cubes

5. 40.1(con’t) How is exchange accomplished in more complex animal?
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6. 40.1(con’t) What are the advantages of a complex body plan
compared to a simpler one?

7. 40.1(con’t)
Hierarchical Organization of Body Plans – cells tissues organs organ system(table p. 855)
Largest organ? Function?
Multifunctional organ? Function?
Tissue Structure and Function – 4 main categories
1. epithelial
2. connective
3. muscle
4. nervous

8. 40.1 (con’t)
Epithelial Tissue – outside covering/lines organs and cavities
tight junctions
barrier against mechanical injury, pathogens, and fluid loss
Cell shape – cuboidal, columnar, or squamous
Simple, stratified, or pseudostratified
Shape is related to function

9. 40.1(con’t)
Connective tissue – bind and support other tissues in the body/sparse population of cells scattered throughout an extracellular matrix
6 major types – loose c.t., cartilage, fibrous c.t., adipose tissue, blood, and bone
Connective tissue fibers – collagenous, elastic, and reticular
Collagenous – strength and flexibility
Elastic – easily stretched, but resilient
Reticular – thin and branched/join c.t. to adjacent tissue
Cell types – fibroblasts –secrete protein of extracellular fibers and macrophages – roam to engulf foreign particles and debris of dead cells

10. 40.1(con’t)
Muscle Tissue – responsible for body movement/actin and myosin/energy consuming
Types – skeletal, cardiac, and smooth
Nervous tissue – to sense stimuli and transmit signals in the form of nerve impulses from one part of animal to another
Neurons, glial cells

11. 40.1(con’t)
Coordination and control – endocrine and nervous/gradual vs immediate and rapid response
Hormones – only cells with receptors respond/cells can have more than 1 receptor type/slow acting but can be long lasting
Nerve impulse – axons
Impulse received by: other neurons, muscle cells, endocrine cells, and exocrine cells
Both chemical and electrical
Fast acting, short duration

12. 40.2 Feedback control loops maintain the internal environment in many animals
Regulating and Conforming – regulate internal conditions despite fluctuations in the environment/internal conditions conform to external conditions
May regulate some internal conditions and not others
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13. 40.2(con’t) Homeostasis – steady state or internal balance
Ex) body temperature, pH of blood, solute concentration of glucose in blood
- Mechanisms – see Fig – set point, stimulus, sensor, response
- Feedback Loops – negative(a response that reduces the stimulus) vs positive(amplify the stimulus – do not usually contribute to homeostasis)
- Ex) exercise  produce heat sweat evaporative cooling
- acclimatization – temporary change during an animal’s lifetime

14. Thermoregulation – critical to survival – why?
40.3 homeostatic processes for thermoregulation involve form, function, and behavior
Thermoregulation – critical to survival – why?
Endothermy and ectothermy – birds and mammals vs amphibians, lizards, snakes, turtles, many fishes, and most invertebrates
Heat generated by metabolism vs gained from environment
Variation in body temperature – poikilotherm vs homeotherm(constant body temperature)
Balancing heat loss and gain – conduction, convection, radiation, and evaporation

15. 40.3(con’t)
Insulation – reduces flow of heat between an animal and its environment
Ex) hair, feathers, layers of fat

16. 40.3(con’t) Circulatory Adaptations – regulate blood flow/heat flow
Vasodilation – increase in diameter of blood vessels
Vasoconstriction – reduces blood flow and heat transfer
Countercurrent exchange – the flow of adjacent fluids in opposing directions that maximizes transfer rates of heat or solutes

17. 40.3(con’t)

18. 40.3(con’t)
Cooling by evaporative heat loss – water absorbs heat when it evaporates
Panting, sweating
Behavioral responses – hibernation, migration
Sun or shade for ectotherms
Bees huddle together