Question

1. Describe conditions of early Earth that existed before the origin of life. Your description should include a brief explanation of the “massive bombardment” in addition to the other significant characteristics of early Earth.

2. Define evo-devo, heterochrony, and paedomorphosis. Describe an example to help explain the meaning of each of these terms.

3. Explain how the evolution of changes in temporal and spatial developmental dynamics can result in evolutionary novelties.(Suggested length of answer is a short paragraph, 2-5 sentences).

4. Explain why extracting a single (linear) evolutionary progression from a fossil record can be misleading. (Suggested length of answer is a short paragraph, 3-6 sentences).

5. Explain the statement: “Evolutionary change is not goal-directed”. (Suggested length of answer is 3-6 sentences.)

Answer 1

1) Earth is made out of same matter as other planet in our solar system but it support life. Earth began to form 4.6 billion year ago from the cloud of gases ( hydrogen, helium) and interstellar dust that formed our sun, the rest of our solar system and even our galaxy. Earth is formed under so much heat and pressure that it is forned as molten planet. During hedean period earth is bombarded continously by remanants of dust and debris like asteroids , meteors and comets untill it form ito solid sphere, pulled into orbit around sun and begin to cool down.

As earth began to take solid form there is no oxygen in the atmosphere. It was so hot that water droplet in its atmosphere couldnt settle to form ice and surface water. That time earth was poisonus because presence of hydrogen and helium gases . That was primary atmosphere of earth.

Secondary atmosphere of earth formed from the out gassing of such volatile compound as water vapour, CO, HCl, methane, ammonia, and sulfer produced by constant volcanic eruption that besieged the earth. It had no free oxygen. About 4.1 billion year ago , earth surface and crust began to cool down , stablize abd creating solid surface with rocky terrain result in cloud formation and rainwater formed the ocean present on earth today.

Development of ocean lead to origin of life on earth.

2) evo- devo means research between evolutionary and developmental biology. It represent mechanism of development have been influenced by evolutionary forces. For example how evolution affect embryo development.

Heterochrony : An evolutionary changes in the rate or timing of development events. For example long neck aquire by girrafes, extentding the growth of seven vertibrae by extending the bone growth in the embryo, not by adding more bones.

Paedomorphosis : if reproductive organ develop faster than other organ then the sexually mature stage of species may retain body feature that were juvenile structure in anchestral species. For example : Axolots retain gills and fins as adult , these are juvenile feature in most amphibians.