Ch. 40 Basic Principles of Animal Form and Function LO 2.9 The student is able to represent graphically or model quantitatively the exchange of molecules between an organism and its environment, and the subsequent use of these molecules to build new molecules that facilitate dynamic homeostasis, growth and reproduction. LO 2.12 The student is able to use representations and models to analyze situations or solve problems qualitatively and quantitatively to investigate whether dynamic homeostasis is maintained by the active movement of molecules across membranes. LO 2.21 The student is able to justify the selection of the kind of data needed to answer scientific questions about the relevant mechanism that organisms use to respond to changes in their external environment. LO 2.25 The student can construct explanations based on scientific evidence that homeostatic mechanisms reflect continuity due to common ancestry and/or divergence due to adaptation in different environments. LO 2.26 The student is able to analyze data to identify phylogenetic patterns or relationships, showing that homeostatic mechanisms reflect both continuity due to common ancestry and change due to evolution in different environments. LO 2.27 The student is able to connect differences in the environment with the evolution of homeostatic mechanisms. LO 2.28 The student is able to use representations or models to analyze quantitatively and qualitatively the effects of disruptions to dynamic homeostasis in biological systems. LO 2.34 The student is able to describe the role of programmed cell death in development and differentiation, the reuse of molecules, and the maintenance of dynamic homeostasis.

Overview We are starting the anatomy and physiology unit: Anatomy – biological form (structure of organisms) Physiology – biological function (how the structures work) EX: a jackrabbit has large ears (anatomy) to help regulate temperature (physiology)

40.1 Animal Form and Function Are Correlated At All Levels of Organization Evolution of Animal Size and Shape Convergent evolution – fast swimmers have similar anatomies. Arms race – how big can your body get before it collapses of its own weight? How will you get the energy all of your cells need if you have a lot more of them? (Irish Elk – horns got so big it couldn’t move anymore and went extinct!) Seal Tuna Penguin

Exchange with the Environment Either every cell of an organisms needs to be in direct contact with the outside world (amoeba & hydra) or it requires a way to transport materials to its cells. Interstitial fluid surrounds cells for and holds materials outside of it. Branching or folding of tissues increases the surface area:volume, thus increasing the ability for exchange. External environment Food Mouth Animal body Respiratory system CO2 O2 Lung tissue (SEM) Cells Interstitial fluid Excretory Circulatory Nutrients Digestive Heart B l o d Blood vessels in kidney (SEM) Lining of small intestine (SEM) Anus 100 m Unabsorbed matter (feces) 50 m 250 m Metabolic waste products (nitrogenous waste)

Hierarchical Organization of Body Plans Cells  Tissues (epithelial, connective, muscle, & nervous) Organs  Organ Systems (digestive, circulatory, respiratory, immune/lymphatic, excretory, endocrine, reproductive, nervous, integumentary, skeletal, & muscular)

Coordination and Control Endocrine System: Hormones travel through the bloodstream throughout the whole body but only effect cells with the appropriate receptor for it. Slow acting and long-lasting effects, such as growth/development, reproduction, and metabolism. Nervous System: Impulse between specific target cells (neurons, muscle, endocrine, and exocrine cells). Very fast.

40.2 Feedback Control Maintains the Internal Environment in Many Animals Regulators maintain a constant internal environment despite changes in its surroundings. Conformers’ internal environment changes with the surroundings. Some organisms do both (Ex: bass regulate solute concentrations but conform to temperature).

Homeostasis “Steady State;” maintaining a constant internal environment. Mechanism (like room temp.) for a variable: Set point (or range): the needed value to maintain Stimulus: fluctuates the above/below set point Response: a sensor sends a signal to the control center (brain) triggering a physiological activity that helps return it to the set point. Negative Feedback – reduces/dampens the stimulus Positive Feedback – amplifies stimulus

Animation: Negative Feedback Right-click slide / select “Play” © 2011 Pearson Education, Inc.

Animation: Positive Feedback Right-click slide / select “Play” © 2011 Pearson Education, Inc.

Alterations in Homeostasis Set points change according to things such as time and age. Circadian rhythms cause physiological changes ever ~24hrs. Disruptions in these can be conformed to but it take time, called acclimatization. (Ex: jet lag).

40.3 Homeostatic Processes for Thermoregulation Involve Form, Function, and Behavior Thermoreguation Endotherms are warmed by their metabolism (“warm-blooded”) Ectotherms are warmed by their environment (“cold-blooded”) Balancing Heat Loss and Gain Radiation: emission of electromagnetic waves by all objects warmer than absolute 0. Evaporation: removal of heat from the surface of a liquid that is losing some of its molecules as gas. Convection: transfer of heat by the movement of air or liquid past a surface. Conduction: is the direct transfer of thermal motion (heat) between molecules of objects in contact with each other.

Insulation: fur, feathers, and blubber Circulatory Adaptations Blood flows to skin increasing loss of heat Restricting blood flow to skin keeps blood from getting too hot on hot days. Countercurrent exchange Warm-blood (arteries) are close to cooler blood (veins) which flow in opposite directions (countercurrent) Some heat transfers from arterial blood to venous blood.