Question

 

1. briefly describe the Urey-Miller experiment, then identify the significance (i.e. what did it tell us about the origin of life?).

2. Pick an animal, then define the species using the biological species concept.

3. Compare and contrast analogous and homologous structures.

4. Compare and contrast microevolution and macroevolution.

5. Compare and contrast background and mass extinctions.

Answer 1

A. Urey Miller experiment was a chemical experiment. In this experiment organic compounds made out of inorganic compounds by applying a form of energy. It could be formed spontaneously by stimulating the conditions of earth 's early atmosphere. This experiment was recognised as an important breakthrough in the study of origin of life.

In 1950 "s biochemist Stanley Miller and Harold Urey conducted Miller urey experiment. In this experiment they demonstrated that several organic compounds could be formed spontaneously by stimulating the condition of Earth's early atmosphere.

The created a Methane- Ammonia,- hydrogen and water mixture to simulate the primordial atmosphere. They subjected that the above mixture to a spark of 75000 volts, this simulated the Lightning of of primitive Earth. Then they provided temperature of 800 degree Celsius. So basically , the methane - Ammonia -hydrogen was taken in ratio of 2 :2:1 along with all these heated products and were passed through a condenser which on condensation yielded aqueous end products. This product contains amino acid aldehydes, etc all major organic compounds four precursorss for life . Amino acids as we know are essential precursors of nucleic acids.

The Miller urey experiment was immediately recognised as I an important breakthrough in the study of the origin of life. It was received as confirmation that several of the key molecules of life could have been synthesized on the primitive earth .

​​​​​​Biological species is a group of organisms that can potentially inter breed or mate , with an another to produce viable, fertile offsprings. For example when a female horse and a male donkey mate they produce hybrid offspring called mule.

Analogous and homologous structures provide evidence for evolution. Anologous structures are structures that are similar in unrelated organisms. Homologous lstructures are structures that are similar in related organisms because they were inherited from a common ancestor. Homologous structures share an ancestor but serve a different function. But analogous structures serve a similar function but do not share and an ancestor.

Micro evolution usually happens on one or a few gene at a time in a small population.It happens on small scale. While macroevolution happens on a scale that transcends the boundaries of a single species. Macroevolution is a large scale change of many things in larger, groups such as species divergence to create new species.

Background extinction refers to the normal extinction rate. These are species that go extinct simply because not all life can be sustained on earth and some species simply cannot survive. Background extinction occur continuously at a very low rate.

Mass extinction is widespread event that wipe out the majority of living plants and animals