What is Science? * The use of evidence to construct testable explanations and predictions of natural phenomena, as well as the knowledge generated through this process
Key points about the nature of science * Science originates in questions about the natural world * Science uses observations and evidence to construct explanations about phenomena and testable hypotheses * The more observations and other kinds of evidence that support an hypotheses, the stronger is that hypothesis
Scientists
* Employ a variety of techniques to investigate the natural world * Make their explanations public through presentations and publications (meetings and oral presentations) * Critique the explanations proposed by other scientist * In discussing sections of publications * Reviewing manuscripts and grant proposals
Our typical experience * Body temp is 37 degrees C * 1 atm of pressure

What is the highest temperature for life? * 132 degrees C * Cell/body temperatures from -2 to 132 degrees C * High pressure the water is not boiling * Range of pressure: 1 atm to 1100 atm * At the deepest part of the ocean the pressure is 1100 atm * The deep ocean is the most common habitat for life * Conditions at the average death of the ocean is about 2-4 degrees C * 380 atm * no sunlight * Organisms confront a variety of problems due to their environment * Example * Antarctic fishes * Live (and have no body temperatures) at -2 degrees (ectoderm) * Penguins * Endotherm- use their metabolic produced heat to stay warm * Keep warm at similar temperatures * Diving seals * Hold their breath for as long as 90 minutes * Dive down to 1500m for as long as 90 minutes * Deep sea fishes * Found to 7000 m * High pressure, cold, low food availability * Food comes from photosynthesis with happens closer to the surface of the ocean * Rattails * Most common deep sea fish family

* Piezophiles= Barophiles * Bacteria- pressure loving bacteria * Need high pressure to grow * Thrive at pressures that kill surface bacteria * Thermophiles * Organisms that love high temperatures * Exist at temperatures up to 132 degrees C * Grow at 122 degrees C * These can be found on hypothermal vents on the sea floor * Hot water is being vented from the stream * Called black smokers * Sharks * Live with ½ molar urea in their tissue * Urea is a chemical used to denature protein

* Halophiles * Organisms that love salt * Live in equilibrium with 3 molar salt * Tuna * Raise the temperature of their muscles about 15 degrees higher than the temperature that they live in * Are endotherms in contrast to ectothermic fish * Set their body temperature to metabolic heat * White shark * Swordfish * Gutless Tubeworms * Don’t have a mouth * Thrive at deep-sea hydrothermal vents * Hot water comes from the sea floor * Red tentacles from the hemoglobin * Can be 6ft in length * They have bacteria the lives in their bodies that can take chemicals and convert it into food * Midwater fish and invertebrates * Organisms living in the water column achieves neutral buoyancy despite the high density of biological materials
The body temperature of an endotherm is set by the environmental temperature is FALSE.
All fish are ectoderms
FALSE- tuna shark