The Urey and Miller was conducted in 1952 and published in 1953 by Stanley miller, under the supervision of Harold Urey at the University of Chicago. It proposed the possible chance of the inorganic material of some of the basic building blocks of life, given that conditions resembled those of the ancient earth. This was the first ever experiment to test Alexander Oparin’s and J. B. S. Haldane’s hypothesis about the evolution of pre-biotic chemicals and the origin of life on Earth.
They designed an apparatus that mocked the atmosphere of early Earth, Miller gathered molecules which were believed to represent the major components that were believed to be in the atmosphere and placed them into a closed system. A mix of water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2), the materials which were believed to represent the major components of the early Earth’s atmosphere, was used in the experiment in order to test what kind of environment would be needed to allow life to begin.
The chemicals were all sealed and circulated inside a sterile array of glass tubes and flasks connected together in a loop, with one flask half-full of liquid water and another flask containing a pair of electrodes. The liquid water was heated to add water vapour into the chemical mixture and the gases that were formed circulated around the apparatus, mimicking the Earth’s atmosphere. The flask with heated water represented water on the Earth’s surface and the recycled water vapor reenacted the water that evaporates from lakes and seas, before going into the atmosphere and becoming into rain.
Sparks were fired between the electrodes to mimic lightning storms (which were believed to be common on the early earth) through the water vapors, and then the vapors were cooled again so that the water could condense (which simulated the oceans) and trickled back into the first water flask in a continuous cycle. The Urey and Miller experiment was an important step in the understanding of the origin of life on Earth, they tested that complex organics could have been created in an environment similar to that of early Earth.
This was conducted to demonstrate that biologically important molecules e. g. amino acids, nucleic acids, sugars, lipids, etc. can in fact be made from nonliving material using natural processes. After only one week of continuous operation, Miller and Urey observed, by analyzing the cooled water, that as much as 10-15% of the carbon within the system was now in the form of organic compounds. Two percent of the carbon had formed several amino acids, including 13 of the 22 that are used to make proteins in living cells, with glycine as the most abundant.
The molecules formed due to the experiment were simple organic molecules that were far from a complete living biochemical system, but the experiment established that the hypothetical processes could produce some building blocks of life without requiring life to synthesize them first. The Urey and Miller experiment has been repeated and the results verified thousands of times in labs all over the world. It was one of the most important steps toward our modern knowledge of the chemistry of the early Earth. Humans really didn’t know what Earth was like 3 or 4 billion years ago and there were all sorts of theories and speculations.
A large area of dispute in the field of science was what the atmosphere was like. It was suggested by Harold Urey that Earth had a reducing atmosphere which meant it contained Ammonia, Methane, Hydrogen and water ( This was Alexander Oparin’s and J. B. S. Haldane’s hypothesis ). This experiment brought to light that the composition of the primitive Earth could have likely been formed this way. Diagram of the Urey and Miller experiment: Part B With new information and technology being available to scientist over time it’s no surprise that the knowledge humans have about the platypus within the last 200 years have continued to develop.
Early in the discovery of the platypus it was thought to be a prank of some sort and that someone had taken different parts of animals and sewn them together, however after investigation into the platypus it was found to be real. Further in time it was believed that platypuses were a mix of reptiles and mammals, monotremes and marsupials were more closely related to each other than to placental mammals. New research has established that the monotremes represent a completely different evolutionary path that branched away from a common mammalian ancestor even before the appearance of marsupials and placentals.
Evidence for this theory has been backed up by researchers at the Australian National University, they found that the platypus has ten sex chromosomes compared to the two in other mammals. Even more alarming was the detection of the platypuses ‘electric bill’. Current research has also shown that the platypus has a unique arrangement of electroreceptor and mechanoreceptors in the skin of its bill, which are believed to help it detect electrical signals, then relay the message back to the brain, creating an image of the riverbed and pressure impulses from its prey and locating it.
The Electron microscope was an advancement in technology which allowed scientists to take a much closer look at the platypus, since the electron microscope new ideas of the platypus has continued to emerge. Due to this invention scientist knowledge on the mysterious bill of the Platypus has also grown, they noticed that it vigorously swept from side to side during hunting and rummaging for food. What was discovered about the amazing bill of the Platypus was a shock to scientists; Thousands of ultra-sensitive touch receptors stream messages back to the brain, helping the Platypus to navigate its way through the streams with its eyes closed.
It could also be used to detect prey, if touched. The electron microscope has been the most important invention in providing new information to scientist about the platypus. Up until the 1930s it was a mystery to humans how platypuses were able to find food, as it was observed that they did not use their senses while they were underwater. The electron microscope also provided scientists with more information about the cells of the platypus which allowed the scientists to gain more knowledge about the biological adaptations of the platypus. In the late 1930s and early 1940s, an innovation was developed by Dr. David Fleay, an Australian that mimicked and stimulated the natural environment of the platypus. This enabled platypuses to be bred in captivity and over the years, has led to the increased knowledge of the breeding and lifestyle habits of the platypus.
Heinemen Biology http://www. daviddarling. info/encyclopedia/M/MillerUreyexp. html Accessed 17/7/10 http://www. accessexcellence. org/WN/NM/miller. php Accessed 17/7/10 http://www. allempires. com/article/index. php? q=The_Platypus Accessed 18/7/10 http://science. jrank. org/pages/4344/Miller-Urey-Experiment. html Accessed 18/7/10