Question

As an aspiring gardener, Thomas hopes to use knowledge gained in biology class to better understand his tomato plants.

A.  Thomas weighs his tomatoes after harvest, and notes that tomatoes are made up primarily of Carbon and Water. From where did these main components originate, and how were they incorporated into the tomatoes?  (3pts)

B. Thomas calculates that in his one-square-meter garden, his plants began with a biomass of 45 grams of Carbon. After three months, he measures the biomass to be 143 grams of Carbon. He also estimates that 32 grams of Carbon were lost through respiration. What was the NPP of his garden over these three months? (2 points)

C. A garden pest eats 30 grams of carbon. Suppose that pest is eaten by a wolf. About how much carbon will the wolf receive that originally came from the garden? (2 points)

D. Thomas notices that his tomato plants have higher productivity with more sun. He thinks back to when he lived in the Sahara desert and about how much sunlight there was in the area. Why was there such low primary productivity in the Sahara desert, despite having plenty of sunlight? (1 point)

E. Where will the energy stored in the tomatoes end up after a very, very, very long time? Explain. (2 points)

Answer 1

A) This carbon originated from the CO2 that the plant took from the air and fixed thorugh the Calvin Benson cycle. Water comes from the soil, the plant's roots absorbed the water form the soil and took all the way into every tissue in the organism, including the fruit (tomato)

B) NPP is calculated by taking the gross primary productivity (in this case it is the quantity of biomass gained) and resting from it the biomass lost by respiration:

NPP = (143-45)-32 = 66g

C) Actually the 30g the pest ate, the predator is going to take the whole biomass from the pest

D) That is because other factors are just not good for plants to live there, the soil is no good for really fixing plants roots and the water resource is not enough to sustain them either

E) After a very long time it will end up in the air as CO2 again, because a primary consumer will eat the tomato, the primary consumer will either respire it into CO2 or be eaten by a secondary consumer or top predator, this predators will eventually respire it into CO2 again