Humans are able to stand on two legs through a complex feedback system that includes several sensory inputs equilibrium and visual along with muscle actuation. In order to gain a better understanding of the workings of the postural feedback mechanism, an individual is asked to stand on a platform to which sensors are attached at the base. Vibration actuators are attached with straps to the individuals calves. As the vibration actuators are stimulated, the individual sways and movements are recorded. It was hypothesized that the human postural dynamics are analogous to those of a cart with a balancing standing pole attached (inverted pendulum). In that case, the dynamics can be described by the following two equations: J d2 dt2 mgl sin t Tbal Tdt Tbaltmgl sin t kJt J _t J Z t 0 tdt where m is the individuals mass; l is the height of the individuals center of gravity; g is the gravitational constant; J is the individuals equivalent moment of inertia; ; , and k are constants given by the bodys postural control system; t is the individuals angle with respect to a vertical line; Tbal(t) is the torque generated by the body muscles to maintain balance; and Tdt is the external torque input disturbance. Find the transfer function s Tds (Johansson, 1988).
Animal form and function lecture: 10/22/2016 1. Horned lizard has incredibly large liver for formic acid, is found on top of the Sandia’s and they give live birth but they eggs are kept within the female. 2. What is an animal Anthozoan (means plantanimals). All animals are multicellular heterotrophs. o What does the lizard have in common with Anthozoan Radial symmetry, ectodermal and endodermal tissues, the ability to move/movement (nervous system attached to muscles), true tissue layers, and a digestive system. o It comes down to how they interact with their environment and how they eat food 3. The dragonfly is the worlds most efficient predator. They can no longer walk because their legs are so well adapted to grabbing insects out of the air. The muscle in the thorax causes two beats of the wings with one contraction. 4. Animals are adapted to specific environments. Desert iguanas can get to 115F before they have to cool down. They have to survive, reproduce and find food with their environment. A tradeoff with the grouper and the tuna is maneuverability vs. speed. 5. Convergent Evolution: In regards to living in water, the general body shape is tear drop and elongated. o The rock cod is ectothermic; they never have to worry about fluctuating body temperature. They have to produce this antifreeze to keep them from freezing 6. Size and Shape affect the way an animal interacts with its environment. 7. Adaptations: Traits that allow animals to survive in their environment. (i.e forked tongue in pit vipers is for detecting minor changes in smell and taste) 8. There is never a perfectly adapted organism. There are a lot of tradeoffs in wing shapes, like the Western Screech Owl and the Brown Boobie (the owl has more maneuverability) 9. Type 1 muscles has very good endurance capacity (a lot of mitochondria in the cells to produce a lot of ATP). Type 2 muscles Large skeletal muscle (fastswitch muscles) glycolytic, produces ATP through substrate level phosphorylation, can generate a lot of power all at once. The trade off is endurance (cardio capacity) vs. strength (using all the energy at once). 10. You cannot adapt to your environment, it depends on a unit of time and adaptation is caused solely by adaptive evolution. We can acclimate to our environment, like melanin production varies according to sun exposure. Genetics play a role in how much you can acclimate. Your genes can affect how well you can acclimate 11. The structure of the cell correlates with function at all scales. The differences in membrane structures differs in cold water vs. warm water. Unsaturated fat changes the shape of the tail (has c=c) and keeps the liquid at colder temperatures. o We require omega 4 and omega 6 because cannot produce these. Its better to eat colder water fish because they produce unsaturated fats so they can maintain membrane fluidity. o Fats contain enormous amounts of energy. Unsaturated fats are less dense and our enzymes break down and do not stack as easily. When saturated fats stack they can form plaque in your arteries. 12. All cells on this planet have to use a ETC and proton pumping gradient. This generates a proton gradient that makes a lot of ATP. We can thank cyanobacteria for form and function. Look at the process of oxidative phosphorylation. 13. We have four different types of tissue in the human body: connective, nervous, muscle, and epithelial tissue. 14. Embryonic cells give rise to three tissue layers: mesoderm, endoderm and ectoderm. o Epithelial Tissue: Skin and digestive tract is all epithelial cells. Covers the outside of the body and the organs. Epithelial cells are constantly replaced and undergo apoptosis. Celia are constantly removing things from our lungs. The microvilli are for increasing surface are to increase absorption. Giardia and other pathogens produce toxins that causes diarrhea, they attack the epithelial cells. o Connective Tissue: Collagen holds animals together (this is very much an animal feature), you can only produce it in the presence of oxygen. Tendons (muscle to bone) and ligaments (bone to bone) are made up of collagen. Bone, adipose tissue and blood cells are a type of connective tissues as well. Bones in Osteichthyes, allowed us to make the transition from going to water to land. Happy Studying Animal Form and Function Lecture 2 March 24, 2016 1. Collagen is unique to animals. It holds animals together and you can’t make it without oxygen because it needs to be oxidized. We couldn’t have evolved without oxygen in the air. 2. Connective tissue also forms blood cells, develops both the red and white blood cells. All cells have the same genes; they just express their genes differently based on chemical signals. a. Connective tissue also forms adipose tissue. 3. Muscle tissue is a uniquely animal feature. a. Smooth muscle (internal organs), cardiac muscle (heart), skeletal muscle (leg). Cardiac muscle works your entire life (like your heart pumping). 4. Nervous tissue: Receiving, processing, and transmission of information. (Neurons, Dendrites, Axons). a. Sends signals across a synapse. Look at the structure of a typical neuron. 5. Organ Systems: Digestive system in two types of chordates (Hagfish vs. Humans). We have a tube that goes from our mouth to our anus. a. Animals cannot digest cellulose (Cows and Termites have organisms that help them break this down). b. The structure correlates with function at all scales. An appendix is probably not a vestigial organ, but it houses the positive bacteria. 6. Structure correlates with function, like birds (Darwin’s Finches) foraging habits and their wings and bills. The bills are adapted to cracking shells or eating insects. a. The woodpecker finch is a tool user. 7. How does the body size affect animals In water (because it is viscous), a blue fish tuna will swiftly move through the water. For a smaller fish it takes more energy because the water feels thicker. a. Body size is important because it affects your surface area to volume ratio. With animals as you get larger your volume gets larger and your surface are decreases at a nonlinear rate. b. This has a lot of implications for animals. The metabolism will scale with size, the larger an animal, the less and less energy it will use proportionally. It uses less energy per gram than a smaller organism. c. Proportionally an elephant eats a lot less than a shrew. A small endothermic mammal will require more energy pound for pound then an elephant. This is because a smaller animal has a higher energy rate then an elephant. d. As you get smaller and smaller the surface area decreases and more heat is being lost rapidly. e. Metabolic rate scales to body size but not in a linear way. 8. First Law of Thermodynamics: Energy cannot be lost or made but it can be transformed or transferred. 9. Second Law of Thermodynamics: Entropy, all systems tend towards high entropy. Any closed system, the energy will be converted to heat and it will be lost and Gibbs Free Energy will go down. 10. Most of the energy exiting our body is by heat and some is lost through waste. a. A really large endotherm may not be able to dissipate heat fast enough. Therefore, they have a slower metabolism. 11. Physical limitations on size: Heat being lost to the environment plays a role on the size of organisms and on the environments as well. a. A whale goes after krill because smaller animals have more energy. We can’t have very large predators because more energy will be lost and you cannot take enough energy to sustain yourself as a large predator. b. Hummingbirds are very tiny and lose heat very quickly and will die within hours of not eating. They sleep at night by going into torpor. c. Mammals are so small and require so much energy and will allow their body temperature to decline (torpor) and they will conserve energy. 12. Relationship between size and body plan: If you are really large then you have small surface area but a large volume and vise versa for smaller animals. If you are really large then you have to find a way to increase surface area to move things around easier. a. If you are a really small animal, then you will have a really small circulatory system. b. Dragonflies rely on diffusion that allow gases to exchange without active movement and they have an open circulatory system. c. Humans have a closed circulatory system where our blood is always in vessels whereas in an insect pump it into their abdomen. d. When we look at extinct animals, like the TRex, they had a very large bite force and although they were a predator they were also scavengers. 13. All animals maintain homeostasis. Every organism on this planet is an island of entropy (a measurement of disorder). Homeostasis is the maintenance of internal balance. a. A living organism has very low entropy and the around them has a very high entropy. b. Life maintains an internal environment that is different from the outside world, this is homeostasis and this internal environment can be represented by an organism. c. A happy herper has a set point (98 F body temp, 7.4 blood pH, 710 mg glucose/L). 14. Two approaches to achieving homeostasis. a. Conformation to one’s environment b. Regulation (this requires energy). An example is a Largemouth Bass that is a temperature conformer. c. The important of maintaining homeostasis is about maintaining proteins and enzymes. Each protein has an optimal temperature and without that temperature it will slow down. Temperature and pH is very important for enzyme activity. d. After the enzymes get too hot then they denature. e. Cells spend lots of energy maintaining homeostasis. 15. Important of thermoregulation: membrane fluidity, which one is the membrane of a warm water fish. a. You take warm adaptive fish in cold water and put it into water then it will die because it wont be able to maintain membrane fluidity. 16. We maintain homeostasis through negative feedback and maintaining internal balance (too hot = go into the shade, and too cold = step into the sun). 17. Ketoacidosis: Maintaining proper blood pH. When a person has this they are diabetic and they lose weight rapidly because their muscle cells are not getting the glucose they need, so the body goes into starvation and starts breaking down fats to produce key tones and the pH in your blood goes down and so calcium bicarbonate is released into the blood system from the bones. a. Keytones make the breath and the urine smell sweet b. This depletes your bones of minerals, and one will develop a calcium deficiency. 18. Regulating body temperature: each species has an optimal temperature. a. Endothermic: heat generated by metabolism. Birds and mammals are endothermic, but those who do not maintain the same body temperature all day and fluctuate rapidly are Heterotherms. Homeotherms have body temperatures that only fluctuate a couple of degrees throughout the day. b. Ectothermic: Relies on heat from the environment. Ectotherms have body temperatures that vary seasonally. c. The trade off between these two is that endotherms can be active at any time regardless of the temperature but it requires an enormous amount of energy. An Ectotherm spends a lot less energy and can get the heat by the behavior (basking in the sun) and spends a lot less energy, however you have to spend a lot more time heating up. Happy Studying