Ch 40 – Animal Form & Function. Form & function. Evolution of Animal size & shape Constrained by physical forces Convergent evolution i.e. fusiform shape for aquatic animals. Seal. Penguin. Exchange with Environment. Mouth. Gastrovascular cavity.
(a) Single cell
(b) Two layers of cells
Advantages of a complex body:
Better able to deal with environmental changes
Countercurrent heat exchange – in many birds & mammals, also sharks, dolphins
Metabolic rate called the hypothalamusis the amount of energy an animal uses in a unit of time
How can metabolic rate be measured?
Influences on metabolic rate called the hypothalamus
Size – rate is proportional to body mass, smaller animals have higher metabolic rate per gram than larger animals
Reproduction – high energy cost
strategies: seasonal reproduction,
life history strategy – i.e. diapause (in insects)