Category Archives: IBHL-1 Biology

D.1a Origin of Life

Data-based question: the Murchison meteorite 

1. In both the Murchison meteorite and Miller-Urey experiment, glycine, alanine, isovaline, norvaline, and aspartic acid are found in equal amounts. However the Murchison meteorite contains more alpha-aminoso0butyrc acid, valine, proline, and pipecolic acid than the Miller- Urey experiment. Also, the Miller-Urey experiment contains more alpha-amino-N-butyric acid and N-ethylglycine.

2. Based on this conclusion, it seems as though meteorites could have started life on earth due to the molecules that were found.

5.5B Classification

Data-based question: a simple food web

1. Both are part of the highest trophic levels of the food web. However, B. bakeri is more productive

2. Ranatra montezuma and Belostoma bakeri

3a. Metaphyton –> Hyalella montezuma –> Telebasis salva –> Belostoma bakeri

3b. Telebasis salva

5. -95%

6. Some organisms can be considered to be in more than one trophic level. Also, some organisms, as they grow older and bigger, move up trophic levels.

5.5a Classification

Data-Based Question: Classifying Cartilaginous Fish

1a. 2 orders are needed to classify the 8 species of fish. They ca be separated s we  into two  groups–the flat (stingray) fish and the thin streamlined fish (shark-like).

2. The fish on the right in the middle row, since this fish seems like a cross between the streamlined fish and flat/square fish. It has a flat body but a streamlined tail.

5.3 Populations

1. One factor could be limited food sources. Another factor could be increased competition within the population.


5.4b Evolution

Data-based question: Galapagos finches

1a. Since 1995, the population increases until 2003, from which it starts to decrease.

1b. Firstly, both populations peak at 2003 and then start to decline. Secondly, the G. fortis population is much higher than the G. magnirostris population. Lastly,

2. Minimun= 294 birds per km2

maximum= 4411 birds per km2

5.4a Evolution

Data-based question: domestication of corn 

1. 1114% increase in length

2. 2633% increase in yield

3. There are several factors that will be selected for farmers such as the texture of the seed and the color.


5.2 Greenhouse Effect

Data-based question: phenology 

1a. 1990

1b. 1970

2a. The higher the leaves are, the earlier the chestnut seeds open.


5.1b Communities and Ecosystems

Data-based question: a simple food web 

1. Both the Belostoma bakeri and Ranatra montezuma are the highest predators. They also are part of more than tropic level, however Belostama bakeri is more productive than Ranatra montezuma.  

2. Ranatra montezuma and Belostama bakeri both occupy more than one trophic level because they are secondary, tertiary,  and quartenary consumers.



5. 95.3% of energy was lost

6.Firstly it is hard because some organisms do not occupy just one trophic level. Also, at different times in the organism’s life it can be part of different trophic levels.

7. It is would be better if the percentage or fraction of what was consumed by each organism was indicated.

5.1a Communities and Ecosystems

Data-based question: fishing down marine food webs 

1. We can check what is in the stomach of the fish to determine what trophic levels it has consumed therefore, determining what trophic level the fish is in.

2a. Over the years, both the fresh water fish and marine fish have decreased trophic levels. However, the marine fish have a more constant decrease where has the fresh water fish have a faster rate of decline.


3. Increasing the age means that the size increases as well, which would mean that the range of prey would increase as well.

4. If the trophic level is lowered, the age is lowered as well. This is because they are related to each other.




9.3b Reproduction in Angiospermophytes

Chapter 10 questions 

1ai. Plants increase the sugar concentration by active transport in sugar.

1aii. This creates a higher solute concentration as water is drawn in by osmosis.

1bi. As the sucrose increases, the percentage of oligosaccharides also increases. At the beginning, it remains constant, it starts increasing at 0.25 mol of sucrose then at 0.5 mol of sucrose it begins to become constant once again.

1bii. This can be done to reduce water loss from the gut cells by osmosis.

2a. Apical meristems allow stem and root growth

2b. The bulbs allow for food storage.

2c. Cotyledons store food in the seeds.


e. The palisade mesophyll allows photosynthesis to occur.

f. PFR stimulates or inhibits flowering depending on whether the plants are short-day plants or long-day plants.

g. The spongy mesophyll allows for gas exchange

h. The tendrils support the plant

i. The waxy cuticle reduces water loss

j. The xylem helps transport water throughout the plant.