1. Chapter 40 Study Guide and Notes

2. 1. & 2. How has natural selection/evolution influenced animal body SIZE and FORM? Physical laws – constrain what natural selection can “invent” – Govern strength, diffusion, movement, heat exchange and therefore limit animal forms Ex. Convergence of body forms in water Size – thicker skeletons are needed as size increases Surface area:Volume – regulates size of individual cells – Diffusion across membranes – Thermoregulation of body heat

3. How do the following organisms exchange materials with their environment? How does their structure help this? Amoeba – Entire surface is in contact with the environment Hydra – Simple organization where all or nearly all cells are in contact with the environment A flatworm – Most cells are in direct contact with environment Whale – Extensively branched or folded surfaces to increase surface area – Interstitial fluid, blood,

4. How are complex body plans advantageous over simple body plans? Can maintain stable internal environment while living in a variable external environment – External skeleton (protection) – Sensory organs (obtain detailed information) – Internal digestion (control release of stored energy) – Filtration system (adjust composition of interstitial fluid bathing animal’s cells)

5. What is the difference between a Regulator and a Conformer ? Regulator – Uses internal control mechanisms to regulate internal change in the face of external fluctuation. – Mammals Conformer – Its internal condition conforms to external changes – Reptiles

6. Give an example of negative feedback in detail

7. What is the difference between an endotherm and an ectotherm Organisms that gain most of their heat from metabolism (cellular respiration) Mammals and birds Organisms that gain most of their heat from external sources Amphibians, reptiles, many fish, most invertebrates

8. List 5 adaptations for thermoregulation Radiation Evaporation heat loss Convection-- Movement of air or liquid past a surface – A breeze to cool organism down – Dilation/constriction of blood vessels Conduction – direct transfer Insulation – Controlled seasonally – Amount of hair, feathers, fat or raising the hair/feathers – Oil secretions to waterproof Circulatory adaptations – Dilation/construction of blood vessels – Countercurrent exchange Behavioral responses Adjusting Metabolic heat production – Shivering, nonshivering thermogenesis, brown fat

9. Explain countercurrent exchange The flow of adjacent fluids in opposing directions that maximizes transfer rates of heat or solutes Blood vessels are arranged antiparallel to one another As warm blood passes through arteries, it transfers heat to the colder boold returning from the extremities in the veins Heat exchange will occur the entire length of the exchanger

10. Basal Metabolic Rate vs. Size

11. Metabolic Rate per kg of body mass vs. body size