Animal homeostasis applies to single-celled and complex organisms Metabolic activities require input of oxygen, nutr

1. Animal homeostasis applies to single-celled and complex organisms Metabolic activities require input of oxygen, nutrients, salts, etc. Waste products must be expelled Internal environment responds to changes in external environment

2. Complex organisms- organ systems how is this coordinated? What systems actually interact with the environment? Intake of metabolic requirements Expulsion of waste Thermoregulation Adjustment of fluid levels

3. Water and osmotic regulation Marine invertebrates are in osmotic equilibrium with their environment Osmotic conformers- as the salinity of the water changes, so does theirs Open sea- very stable environment Organisms that live there don’t tolerate change well (stenohaline)

4. Coasts, estuaries, etc.- conditions are much more unstable and organisms must be able to tolerate change Euryhalines- capable of osmotic regulation shore crab- hyperosmotic- internal salt concentration is higher than that in the environment How?

5. When water moves in, it can be excreted by kidneys Salt loss- active transport by specialized cells in gills to bring salt back into body

6. Osmotic regulation in fresh water organisms must be very good at hyperosmotic regulation Protective covering on body Kidneys that remove excess water Salt-absorbing cells Amphibians use skin to reabsorb salt

7. Marine bony fishes- hypoosmotic regulation (internal salt concentration is lower than that in water) Without regulation would tend to lose water and gain salt Mechanisms: drink seawater sodium chloride is secreted by specialized cells in gills other salts are excreted

8. Sharks and rays raise osmolarity of blood by conserving urea (osmolarity determined by total ion concentration

9. Salt and water balance in terrestrial animals Water loss: evaporation excretion in urine excretion in feces Water replacement: food and water retention of metabolic water (by product of chemical reactions) some insects can absorb water vapor

10. Conversion of urea into uric acid: A toxic waste product is converted to a nontoxic substance Can be excreted as semisolid product with little water loss terrestrial insects reptiles birds; amniotic eggs of same Salt gland- marine birds and turtle- for excretion of salt

11. Excretory structures of invertebrates Contractile vacuole freshwater protozoa, sponges main function is removal of excess water Some products are regulated by diffusion Contractile vacuoles are uncommon in marine protozoans- they are isoosmotic with sea water and don’t need the vacuoles

12. protonephridium

13. Protonephridium Fluid enters system through flame cells Excreted through pores on the surface No centralized excretory system

14. True nephridium is open tubule open at both ends exchange between tubule and bloodstream

15. Vertebrate kidney regulates volume and composition of fluid

16. Glomerular filtration- protein-free filtrate • is passed into glomerulus from blood 2. Filtrate is modified as it passes though tubule system fluid, nutrients and ions are reabsorbed passively, active transport, ion pumps 3. Distal tubule- further adjustment of filtrate concentration under endocrine control 4. Water excretion- loop of Henle

18. Temperature regulation in animals Ectotherms- body temperature is determined by environment (e.g., warm up by basking in the sun) Endotherms- animals generate and retain enough heat to maintain stable body temperature (birds and mammals)

19. General types of adaptations • Rate of heat exchange between animal and • environment • body insulation (hair, feathers, fat) • vasodilation, vasoconstriction • endotherms- countercurrent heat exchange

20. Veins absorb heat from arteries

21. 2. Cooling by evaporative heat loss if humidity is low enough respiratory system (panting) skin (sweating) 3. Behavior _seeking warmth or cold as needed 4. Changing rate of metabolic heat production (endotherms, esp. mammals, birds)

22. Most animals are ectotherms. Some are capable of both, at intervals Invertebrates behavioral and physiological adjustments Bees and large moths can be endothermic flight muscles generate heat honeybees can huddle

23. Amphibians and reptiles- usually ectotherms Low metabolic rates contribute little to body temperature mostly behavioal mechanisms amphibians can control mucus secretion some marine reptiles have vasoconstriction pythons can warm up by shivering while incubating eggs

24. Fishes body temperature is usually similar to that of water Some larger fishes are endothermic swimming muscles generate a lot of heat; circulatory system can help sustain it.

25. Mammals and birds maintain high body temperature; balance metabolic heat production and loss Muscle contraction Hormonal control of metabolic rate (many mammals and some birds) brown fat- heat production Vasodilation, constriction Insulation Evaporative cooling Feedback mechanisms (hypothalamus, skin)

26. Acclimitization Cellular: enzyme levels enzymes with different temperature optima membrane fluidity heat-shock proteins (rapid adjustment) generally help cells survive stress Behavioral: torpor ( slowdown) hibernation (winter)

27. Small animals may have daily torpor Bats and shrews: feed at night, torpor during day Birds: feed in day, torpor at night Helps them conserve energy Animals can be much more accommodating to temperature fluctuations than water and waste imbalances