Melanie+W.

//Effects of Nicotine// //Wikipost #3// //June 6th, 2014// Ever wonder why smokers crave a cigarette when they're in a bad mood or in a stressful situation? It's because nicotine may help people feel calmer, causing temporary feelings of relaxation as well as reducing stress, anxiety and even pain. In spite of that relaxation, though, nicotine actually increases physical stress. media type="custom" key="26164048" (Sry this video is creepy) (I didn't actually watch it) This video is about the effects of nicotine on the brain.

"A synapse is the site where two neurons come into contact. The presynaptic neuron releases a neurotransmitter, which binds to receptors on the postsynaptic cell. This allows signals to be transmitted from neuron to neuron in the brain. Acetylcholine is released from one neuron and binds to receptors on adjacent neurons." (HowStuffWorks.com) Nicotine works directly on the reward center of the brain which is why it is so highly addictive. This picture shows nicotine on a molecular level. On a molecular level, nicotine is made up of carbon, hydrogen, nitrogen and sometimes oxygen. Nicotine is addictive, as addictive as cocaine or heroin -- even if your body absorbs only a tenth of the amount of nicotine in every cigarette you smoke it is enough to get you addicted. This picture includes all of the gross things you may find in cigarettes. Nicotine has a lot of gross stuff in it as well. It is commonly used as an insecticide. Tobacco use of any kind comes with numerous health risks. Tobacco smoke contains at least 250 chemicals known to be toxic or to cause cancer. A smoking habit of just one to four cigarettes a day is enough to increase your chance of developing cardiovascular disease. //References:// [] [|https://www.google.ca/search?q=smoking&source=lnms&tbm=isch&sa=X&ei=qMeRU7TVMKnY8AHk5YG4Cw&ved=0CAYQ_AUoAQ&biw=1242&bih=510#facrc=_&imgdii=_&imgrc=hyO8ggTbgMW-vM%253A%3Bd0tLIom6QDH04M%3Bhttp%253A%252F%252Fdailymuslims.com%252Fwp-content%252Fuploads%252F2013%252F07%252Fsmoking-danger.jpg%3Bhttp%253A%252F%252Fdailymuslims.com%252F2013%252F07%252F09%252Fthe-great-islamic-smoke-out%252F%3B960%3B690]

Further Reading: [] This discusses the psychological effects of nicotine

[] This goes in depth about the downsides of nicotine

[] This discusses the feelings nicotine produces

[] Nicotine in the brain

//Evolution of fish// We all know that fish have fins and tails, but how close are those to your own arms and legs? Although fish can’t walk on land, scientists do believe that fish are the ancestors of land animals. Seeing fish today, it is hard to believe that these sea creatures could have ever walked on land. Though there is "mudskippers" that use the front fins to push themselves up on land, it is still difficult to imagine any fish surviving on land.

Above, a mudskipper using his front fins to propel himself over land.

In evolution creatures from the oceans may have slowly evolved to live and walk on land. Fish have very unique bone structure, so the change in evolution would have changed many different parts of the fish. One way to see these changes is to examine fossils. Most fossils are only the hardened skeletons of creatures. Because muscles and other softer parts of animals do not usually become fossils, it is often more difficult to see the evolutionary pattern of sea creatures.

Below, this picture shows a cross section of pectoral muscles in 4 legged animals (top) bony fish (middle) and sharks (bottom). This shows how closely related these species are. Because lungfish are closest on the tree to tetrapods it means four legged animals and lungfish come from the same ancestor.

In one experiment, scientists used fish embryos, or developing baby fish, that had been bred to have special proteins in their muscles that shine red and green under special light. By taking tissue that forms the pectoral muscles from the red and green shining fish and replacing that same muscle in a fish that only shines green, the researchers could tell whether or not the replaced tissue would end up creating the pectoral muscles. By examining the differences in how fish muscles grow, scientists have a better understanding of how species evolved to live on land over many hundreds of thousands of years.

References: [] [] [] []

Further Reading: Focusing on the evolution of armoured fish: []

Why can some fish live in freshwater, some in salt water and some in both? This link discusses this topic: []

Fossil of a fish that has the same structure as a vertebrae: []

Stories of pre-historic fish: []