BIOL 1108 Edition 1nd Lecture 12 Outline of Last Lecture I Learning Objectives II In The News III Starch and Cellulose IV Plant History Outline of Current Lecture I Learning Objectives II In The News III Negative Feedback IV Homeostasis V Thermoregulation VI Abiotic vs Biotic Factors Current Lecture I II Learning Objectives 1 Practice observing animal FORM and relating it to FUNCTION 2 Be able to de ne homeostasis 3 Be able to draw a generalized homeostatic feedback diagram and understand its t erminology 4 Understand two evolutionary strategies animals have for thermoregulation 5 Consider organisms physiological morphological and behavioral adaptations for thermoregulating within their environments In The News Why did John O Keefe May Britt Moser and Edvard I Moser update their Facebook pages last week These scientists won the 2014 Nobel Prize in Physiology or Medicine for discovering how the brain stores information through the inner GPS navigation 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 III IV of brain cells This discovery can ultimately help nd a cure for brain diseases such as Alzheimer s o Discovery of brain cells that give the body a sense of self location o Sense of space spatial arrangement in mice was measured using electrodes in their brains o Neuron ring was relative to direction of where the mice were facing and spatial cues o Representation of these signals are found in the entorhinal cortex and hippocampus Negative Feedback TOPHAT QUESTION How would you de ne a negative feedback loop A A process whereby a change in an initial condition triggers a response that counteracts the initial change The receptor receives information that something in the environment is changing The control center or integration center receives and processes information from the receptor The effector responds to the commands of the control center by either opposing or enhancing the stimulus This is an ongoing process that continually works to restore and maintain homeostasis Homeostasis The property of a system in which variables are regulated so that internal conditions remain stable and relatively constant Homeostatic regulation involves three parts or mechanisms 1 The receptor 2 The control center 3 The effector V For example in regulating body temperature there are temperature receptors in the skin which communicate information to the brain which is the control center and the effector is our blood vessels and sweat glands in our skin Because the internal and external environment of the body are constantly changing and adjustments must be made continuously to stay at or near the set point homeostasis can be thought of as a synthetic equilibrium Thermoregulation Heat gain and loss a Radiation i The emission of electromagnetic waves by all objects warmer than absolute zero ii Can transfer heat between objects that are not in direct contact as when a lizard absorbs heat radiating from the sun b Evaporation i The removal of heat from the surface of a liquid that is losing some of its molecules as gas ii For example evaporation of water from a lizard s moist surfaces that are exposed to the environment had a strong cooling effect c Convection i The transfer of heat by the movement of air or liquid past a surface as when a breeze contributes to heat loss from a lizard s dry skin or blood moves from the body core to the extremities d Conduction i The direct transfer of thermal motion heat between molecules of objects in direct contact with each other as when a lizard sits a hot rock VI Heat gain loss and environmental interaction relative to organisms physiological morphological and behavioral adaptations Abiotic vs Biotic Factors Abiotic Factors o Temperature hooter near the equator colder near the poles o Land vs Water cool down faster in water than air o Elevation cooler in higher areas and in low areas o Sunlight vs Shade warmer in the sunlight o Vegetation o Water Biotic Factors o Ectotherms heat source from something external Ex Lizard o Endotherms internal metabolistic heat source regulates own heat Ex Walrus