BIO325H5 Lecture Notes - Lecture 2: Airfoil, Wind Shear, Heliotropism
Document Summary
Plant locomotion: spores, seeds, samaras, insect vectors, and growth. Compliance: ease with which a structure is deformed (opposite of rigidity/stiffness) Pulvinus: active movement in plantss: the leaves of many peas & beans are moved up & down in a diurinal rhythm & flexed toward the sun by means of pulvinus (short region at distal end of leaf stalk) Burdock, arctium: function of burdock spines= elasticity, energy imparted to bend spine from the passing mammal dislodges the burr from the plant & fires it into the fur. Importance of getting out of the still boundary layer where breezes & winds can keep the spores aloft & above terminal velocity. The collective discharge of many spores is required to tip the aerodynamic forces in inertial forces. A single spore projected at the same speed would decelerate so fast by viscous drag that it would travel only a few millimeters.
