Monthly Archives: April 2012

5.2 Greenhouse Effect

Data-based question: phenology 

1a. 1990

1b. 1970

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

2b.

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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.

3.

4.

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.

2b.

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.

5.

 

 

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.

d.

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.

9.3a Reproduction in Angiosperms

Data-based question: fire and seed dormancy in a plant of the chaparral 

1. About 0.5 µm.

2. In control seeds, the water is able to penetrate the testa but not the waxy cuticle, therefore it does not reach the embryo.

3a. In smoke treated seeds, water is able to penetrate further than it does in the control seeds. In control seeds, water remains close to the testa however in smoke treated seeds, water is able to penetrate the waxy cuticle and almost reach the embryo.

3b. This can be due to the fire burning the waxy cuticle, allowing water to penetrate and germinate the seeds.

4. Two advantages of ending dormancy after fires in the chaparral are that light and nutrients are available.

9.2b Transport in Angiosperms

Data-based question: the Renner experiment 

1. The clamping of the stem caused the rate of water uptake to go all the way down to zero as the leaves are not receiving water.

2. Cutting the top of the shoot caused the rate of water uptake to decrease. This is due to auxin which is normally located at the top of the shoot. If the top is removed, water uptakes to slow down and become constant. However, because the pumps are added, water uptake rose again.

3. 5.5 cm3 n-1

4. The results show with the atmosphere pressure, the leaves of the shoot uptake more water. However with the vacuum pump and zero pressure, the uptake did not increase nor decrease but remains constant.

9.2a Transport in Angiospermophytes

Data-based question: found hyphae and mineral ion absorption 

1a. The addition of the fungi effected the root dry mass and shoot dry mass of the plant. The Paxillus involutus had the greatest effect on teh grwoth whereas the Pisolithus tinctorius had the smallest effect.

1b. The fungi increase the surface area of the roots which allows more minerals and water to be absorbed.

2a. There is a direct relationship. As the root dry mass increases, the shoot dry mass increases and as the root dry mass decreases, so does the shoot dry mass.

2b. This is due to the fact that if there is more roots, this helps with the plants to grow so it increases the shoot mass as well.

2c. The effects of closely related fungi on tree growth are not exactly the same. While I and II are closely related, the effects on growth they have are not exactly the same because with fungi II, the mass increases less than with fungi I.

 

9.1 Plant Structure & Growth

Without visibly ingesting anything, plants can still grow larger. Using inorganic substances and sunlight plants synthesize a huge range of substances and they can fuel both themselves and most food chains in the terrestrial ecosystems. Plants retain groups of stem cells throughout their lives that allow them to grow indefinitely, and these cells are called meristems. Cells in meristems are small and keep going through the cell cycle to produce more cells by mitosis and cytokinesis. These new cells can absorb nutrients and water so that the volume and mass of the plant increases. Apical meristems are the primary meristems located at the tips of stems and roots. They are responsible for the growth of the root. The shoot of the apical meristem at the tip of the stem is more complex. The stems leaves and roots of plants develop in different ways. Hydrophytes which are plants that grow in water are different that xerophytes that grow in deserts.

Data-based Question: comparing stem structure 

1. The areas on the diagram represent areas of tissue. This is because the structures shown are not single cells but rather show different cells put together so are tissues.

2.The monocotyledon and dicotyledon both have vascular bundles, phloem, and xylem.

3. In both monocotyledon and dicotyledon the phloem is located on the outside and of the stem while the xylem is located inside.

4. Monocotyledon stems cannot thicken as dicotyledon stems because they do not have cambium or lateral meristems which help with the thickness of the stem.