Discussion Questions 4/26

Leslie:

1. To capture reader attention, Leslie begins the article by posing a powerful hypothetical question, and forces the reader to contemplate what life would be like if photosynthesis didn't exist.

2. This could be used in my own case study by following suit and posing a question of the same magnitude, only applied to our topic (Australopithecus Anamensis). One such question could be "Are we direct ancestors of Austrolopithecus Anamensis?

3. Photosynthesis is the process of plants using the light and energy from the sun and transforming it from carbon-monoxide into oxygen.

4. Photosynthesis makes the Earth livable for our ecosystem by supplying the atmosphere with oxygen, which is used as energy to create and sustain the millions of life forms on the planet. Photosynthesis and the oxygen it produces is also responsible for creating the ozone layer, which protects living organisms from the harmful effects of UV rays.

5. The chemical that was the basis of the earliest photosynthesizing microbes was hydrogen sulfide. The chemical that is the basis of most photosynthesizing organisms alive today is water.

6. In photosynthesis, chlorophyll is one of many different substances that absorb light, which is vital in the process. It is also responsible for giving plants their green color.

7. The great oxidation event was a major milestone in the fossil record. About 2.4 billion years ago, scientists first notice a high level of consistent and abundant oxygen in the earth's atmosphere. It is recognized in the fossil record by its red colored sediment that resembles rust.

-Source: Leslie, Mitch. On the Origins of Photosynthesis. Science, Vol. 323. March 6, 2009.

Zimmer:

1. The hook Zimmer uses to capture the reader's attention is to point out the idea that humans and toadstools have more similarities than one might realize.

2. I could adapt this style of introduction into my own case study by pointing out the (controversial) fact that the species Australopithecus Anamensis and humans are more alike than different. Of course, the goal then would be to defend my claim through solid and credible empirical research.

3. Eukaryotes are all living organisms that have a nucleus that manufactures mitochondria.

4. Mitochondria are the components of the cell that function as communication networks to pass along various information about genes or DNA. They evolved by turning bacteria into information that eukaryotes could use.

5. The "hydrogen hypothesis" posits that mitochondria originated as bacteria that consumed carbon and released hydrogen atoms.

6. The three domain hypothesis states that life is essentially divided into three separate branches: eukaryotes, bacteria, and archaea. The eocyte hypothesis states life is only essentially divided into two branches: bacteria and archaea, with eocytes being the ancestors of the eukaryotes.

Source: Zimmer, Carl. "On the Origins of Eukaryotes." Science. Vol. 325. August 7, 2009.