Astronomy Unsw - Phys 1160 Module 3 Answers

The author and his colleagues specifically chose to focus on 375 million year old rocks in their search for fossils because this was the time frame that provided fish that would be useful to study from. The 385 million year old rocks provided fish that look too similar to the ones we have now and the 365 million year old rocks have fossils that don’t resemble fish. The 375 million year old rocks, however, provide fossils that show the transition between fish and land living animals.

Early earth was dominated with carbon dioxide and hydrogen sulfide. Hydrogen sulfide are invisble gas that were poisonous. We think this is when life first took hold. Penny Boston and Diana Northern investigate how life can survived here. They went to a cave, Cueva day Pl lose which was filled with hydrogen sulfide. Life is thriving inside the cave. Single cell bacterias snot tights were here. Bacteria are common organism, grow adapt and reproduce. Many bacteria were found and they survive from the hydrogen sulfide. If they can find life here, then life can be formed in early earth.

5. Do some research to determine the ages of the oldest known fossils. What kind of life forms were they?

1. The author chose to focus on 375 million year old rock because the transition from fins to necks and limbs occurred then. The scientists knew that any time later than this and they would find lots of animals with limbs. But if they searched earlier than this time then there are only fish without necks. When the fish were evolving they evolved necks before they evolved limbs so this was a good sign in chronology. Sedimentary rocks are the best types of rocks for fossil due to their gradual pressure and low amounts of heat. Sedimentary rock is also found in lake beds and streams, where fish and aquatic wildlife are most likely to live.

When oxygen and nitrogen combine in water, it forms nitrate, which is an essential chemical for eukaryotic algae; however, cyanobacteria do not need nitrate for their survival, contrary, they use elemental nitrogen. This way, even after the evolution of true algae, even though in fewer quantity, cyanobacteria remained widespread, and oxygen was accumulated.

2. An interstellar cloud of gas known as an H-II region is mainly composed of what?

1. The earth’s sun is a star, it generates heat and light through nuclear fusion.

I am contacting you on behalf of the Astronomy Club. As you may or may not have heard, the Associated Students of the University of Arizona released a statement to all of the clubs on campus saying that the Appropriations Board had a meeting on March 6th and concluded that it no longer had any more funds to support any of the clubs until further notice. We received this approximately 2 weeks prior to when we had planned to submit our necessary document to request travel funds for our upcoming 2-day trip to the Grand Canyon/Discovery Telescope on the weekend of April 14-16. Therefore, we are contacting you to ask if the department would consider partially funding this event.

The purpose of this study is to identify four unknown organisms. The unknown organisms have been assigned randomly to six-research groups by Professor Hoffman. Each research group was provided two eukaryotes and two prokaryotes. The unknown organisms will fall into the following classifications: bacteria, algae, fungi, or protozoans. All living organisms are organized into one of three domains of life, Bacteria, Archaea, and Eukarya.

Up until 1947, it was believed that the Cambrian Explosion marked the first true abundance of multicellular life. However, this was discovered to be untrue after Sir Douglas Mawson and R.C. Sprigg mistakenly came across numerous "fossil jellyfish" in the Ediacara Hills while observing what was originally believed to be sandstones belonging to the lowest strata of the Cambrian. At first, these finding were dismissed as "fortuitous inorganic markings."(AAS Biographical Memoirs.) Several years later however, other discoveries of segmented worms, worm tracks, and impressions of two other assemblages that bear no resemblance to any known organism, living or extinct, prompted the South Australian Museum and the University of

When life arose on Earth about 4 billion years ago, the first types of cells to evolve were prokaryotic cells. For approximately 2 billion years, prokaryotic-type cells were the only form of life on Earth. The oldest known sedimentary rocks found in Greenland are about 3.8 billion years old. The oldest known fossils are prokaryotic cells, 3.5 billion years in age, found in Western Australia and South Africa. The nature of these fossils, and the chemical composition of the rocks in which they are found, indicates that these first cells made use of simple chemical reactions to produce energy for their metabolism and growth. Eukaryotic cells evolved into being between 1.5 and 2 billion years ago. Eukaryotic cells appear to have arisen from prokaryotic cells, specifically out of the archaea. Indeed, there are many similarities in molecular biology of contemporary archaea and eukaryotes. However, the origin of the eukaryotic organelles, specifically chloroplasts and mitochondria, is explained by evolutionary associations between primitive nucleated cells and certain respiratory and photosynthetic bacteria, which led to the development of these organelles and the associated explosion of eukaryotic diversity. Today Prokaryotes

Next, is the community clay hypothesis. it was created by Alexander Grahm Cairns-smith in the late 1900s. His claim on it is that life was started and crated by layers of clay from the earth. The evidece they backs this up is the process of abiogenesis. His reasoning is that energy from the atmosphere give the clay nutrients and and creates cells after a long

According to astronomical research and geological evidence, scientist indicate the universe is approximately thirteen thousand eight hundred and twenty billion years old. The first link to humanity started with a primate group called Ardipithecus. While our ancestors have been around for about six million years, the modern form of humans only evolved about two hundred thousand years ago. The age of the Earth is estimated about four point fifty four billion years because that is the age of the oldest rocks with fossil evidence of life on earth. The oldest rocks on Earth found to date are the Acasta Gneisses in northwestern Canada near the Great Slave Lake, which are four point three billion years old. The study of the origin of life on Earth, more specifically abiogenesis, is the natural process of life arising from non-living matter. Life on Earth is believed to have began from organic compounds about three point eight to four billion years ago. Despite several competing theories for how life arose on Earth scientist only know when life first appeared on Earth and are still far from answering how it appeared. Since it is hard to prove or disprove them, no fully accepted theories of the origin of life exists.

Life is an amazing and seemingly rare phenomenon. With the materials necessary and the process that had to take place in a certain order, at certain times, it really is a wonder that we are here. What is even more impressive is that we have managed to evolve past single-celled organisms, and into intelligent life forms. With our increased intelligence, there coincides an increased number of questions that need answers. Does other life exist? What do planets need to support life? Where do we go from here? Throughout this paper, I hope to answer these questions, or at least provide some evidence as to what we know so far. The focus will mainly be on the different types of habitable zones, what special resources and properties are required for a potentially habitable planet within one of these zones, and what this all means.

One of the main theories is that life started by chemical means in a rock where water, methane, ammonia and hydrogen were all present then with the added effect of lightening simple organic molecules formed the building blocks of life. There was an experiment that was conducted in 1953 by Miller and Urey that supports that the conditions above could stimulate organic compounds to form. *copied “ The Miller-Urey experiment attempts to recreate the chemical conditions of the primitive Earth in the laboratory, and synthesized some of the building blocks of life.