BIO 373 1st Edition Lecture 6 Outline of Last Lecture I Freshwater Biological Zones a Lotic systems b Lentic systems c Human impact II Marine Biological Zones a Intertidal regions b Coral reef c Pelagic zone d Human impact III Texas biomes IV Temperature Variation and Water Availability a Physiological ecology Outline of Current Lecture I Temperature Variation and Water Availability continued a Plants b Animals c Ectotherms d Endotherms e Variation in Water Availibility i Water potential f Water Balance in terrestrial plants Current Lecture Temperature Variation and Water Availability Temperature Variation in Plants o When transpiring plants give off heat internal temperature decreases Drop leaves to regulate temperature Tradeoff less photosynthesis less energy production Alternatives These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Hairs on leaves o Provides reflectance Guard cells Adjust thickness of boundary layers o Smaller boundary layer heat exchanged easily in warmer environments More color o Absorb more heat More layers of leaves o Thicker boundary layer can hold on to more heat when wind passes or temperatures are low Temperature Variation in Animals o Surface area to volume ratio Larger objects have lower surface area to volume ratio Increase surface area and maintaining volume will decrease surface are to volume ratio Temperature Variation in Ectotherms o Microhabitat selection Ex burrowing when too hot or too cold Ex frogs crystallize internal liquids and produce more solutes freeze their outsides to keep internal of cells aqueous Temperature Variation in Endotherms o Mammals and birds bees and fish too o Metabolic heat Can produce a lot of heat with muscle activity Good endurance athletes can maintain burst of energy for a longer period of time o Tradeoff of endothermy highly energetically costly Limited by resources like food o Small endotherms have higher metabolic rates Small organisms lose heat quickly so must have a very high metabolic rate to maintain heat Ex humming birds o Torpor state of physical inactivity Variation in Water Availability o Marine environments are hyperosmotic More salinity than organisms o Freshwater are isosmotic o Water potential potential for water to do work Water potential osmotic potential pressure potential matric potential Osmotic potential a negative value concentration of solutes less availability with solutes present Pressure potential turgor pressure Matric potential negative related to attraction forces of something to water Moves from high potential to low potential More solutes increased osmotic potential decreased water potential Water Balance in Terrestrial Plants o Amount of water in soil is determined by inputs outputs texture topography o Soil can capture water with adherence Sandy soil bigger particles Clay soil smaller particles Bigger particles lower surface area to volume ratio decreased matric potential Smaller particles increased matric decreased availability for organisms o Daytime movement of water in soil to plants Plants photosynthesize during the day and transpire Gradient of water potential higher in soil than plant Stomata minute pores in the epidermis of the leaf or stem of a plant forming a slit of variable width that allows movement of gases in and out of the intercellular spaces o Adaptations More roots looking for water Protrude roots for oxygen