Lesson 2 part 2

Heterogeneous Mixtures Parts of the mixture are noticeably different from one another Homogenous Mixtures Evenly distributed, hard to tell the difference between one part and another

Type of homogenous mixture When substances dissolve in another Particles are too small to settle out, filtered or scatter light

Water has many properties, but one of the most important is that water acts as a UNIVERSAL solvent Solvent – Substance that does the dissolving Solute – Substance that dissolves in the solvent The solubility of a substance is its ability to dissolve another substance Water is very good at dissolving Hot water can hold more solute (can dissolve more) than cold water

Water’s polarity contribute to water as a universal solvent Salt is part metal, part nonmetal Metal and nonmetal bonding form ionic bonds Ionic bonds form from IONS Elements that have a + or – charge Opposites Attract

Ocean is filled with dissolved particles Elements that have opposite electrical charges are called SALTS This makes a Saline solution Na, Cl, Sulfate, Magnesium, Calcium, Potassium, Bicarbonate Distilled water = no salinity Fresh water is.01% salt or less Ocean average is 3.5% salt or more Every liter has 1.2 ounces of salt

Water’s excellent ability to dissolve solutes means it is carrying materials with it Water does the same in all organisms Where do these salts come from? Fresh water & streams contain salts Rivers dump into the oceans 4 billion tons of salts are emptied into the oceans each year Water also evaporates Leaves behind salts

Inside the Earth Deep Sea Vents From the Atmosphere Wind and Rain carry minerals Human made Only removed by incorporating into rocks, sediments and organisms

Marine organisms are designed to live in the salt water Brackish = in between salty or fresh Mangrove forests and salt marshes Called estuaries Where rivers meet oceans Many juvenile organisms live here “Nursery of the Sea” Also protect coastlines from erosion

Marine organisms go through Osmosis Water moves from low salinity (high water concentration) to high salinity (lower water concentration Osmoconformers- Do not attempt to control solute/water balance Their internal concentration varies as the salinity in the water around them changes Most can only tolerate a very narrow range of salinity

Osmoregulators – These organisms control their internal concentrations – Can generally tolerate a wider range of salinities than osmoconformers – Some animals require different amounts of salt for different life-cycles – This can be done in a variety of ways such as secreting very little urine or using specialized glands to secrete salts as examples

Osmoregulation – Individual cells control the balance of water Mangroves will release salt from their leaves Some sea turtles and marine birds have special salt glands that remove excess salt

In high salt environments, fish and other organisms lose water to the salty sea Must drink more water Adding more salts Need a way to remove the excess salts and maintain homeostasis Constant internal environment Opposite for Freshwater Fish This way cells stay the same size

Marine MAMMALS Do not drink sea water Get water from the food they eat and have a higher urine salt concentration

Maintain neutral buoyancy Float, sink Less dense than water