Astronomy Unsw - Phys 1160 Module 3 Answers

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

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.

Describe the important chemistry of early earth and how this may have given rise to life forms.

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

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

During the Cambrian Period there was an explosion of life forms. Most of these were in the water. Many animals with no backbones lived in the shallow seas. These animals were invertebrates.

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

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.

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.

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.

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.

was the first to evolve naturally from materials already common in the pre-biotic Earth. Self-replication

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

What is life? This is a difficult question to answer, largely because life itself is not a simple concept. About four thousand five hundred million years ago the Earth collided with a planetoid the size of Mars. At this time, fragments orbiting the Earth formed the

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.