thebiotutor.com 4A Organisms & Environment Time: 35 minutes Total marks available: 35 Total marks achieved: Andy Todd

Transcription

1 thebiotutor.com 4A Organisms & Environment Time: 35 minutes Total marks available: 35 Total marks achieved:

2 Q1. The table describes four different geographical regions. It also gives the amount of energy converted into plant biomass each year in each region. (a) Plot a bar graph on the grid to show the amount of energy converted into plant biomass each year in each region. (5)

3 (b) The amount of energy converted into plant biomass each year depends on the effect that abiotic (non-living) factors have on the rate of photosynthesis. Carbon dioxide is one of these abiotic factors. Name three other abiotic factors likely to affect the rate of photosynthesis. (3) (c) Regions C and D have the same climate. Plants grown in region D have more energy converted into plant biomass than plants grown in region C. One reason for this is the use of selective breeding to produce high yielding crops. (i) Suggest two other reasons for more energy being converted into plant biomass in region D. (2) (ii) What is meant by the term selective breeding? (d) Describe how you could use a quadrat to estimate the plant biomass in one of the regions. (4) (4)

4 (Total for question = 18 marks)

5 Q2. A student wanted to investigate the factors that influence the activity of soil organisms in a woodland. She decided to study one species of woodlouse, a small animal found under stones and rotting wood in damp and dark places. She used a trap to collect organisms in the woodland during the day time and during the night time. She counted the organisms collected before releasing them. From the day time sample she produced a table of results. (a) Complete the table below to show the results for the night time sample. (2)

6 (b) Use the data from the day time and night time samples to draw a bar chart to compare the number of organisms collected. (5)

7 (c) (i) Compare the number of organisms collected during the day time and during night time. (ii) Suggest an explanation for the change in the numbers of woodlice. (d) The organisms caught in the trap remained there for up to 10 hours before being counted. Suggest how this might affect the results obtained. (e) Ecology involves the study of organisms in their environment. With reference to the investigation in this question, explain the terms (i) population (ii) community (iii) habitat (3) (2) (2) (1) (1) (1)

8 (Total for question = 17 marks) Q1. In part (a) of this question most students were able to score at least 4 marks with excellent bar charts. The most common loss of a mark was for not labelling the axes fully, including appropriate units. Part (b) was well answered with most showing good understanding of abiotic factors that affect photosynthesis, temperature and light being the most common responses. A few gave vague references to humidity and wind speed confusing it with transpiration. Part (c)(i) was challenging for many. The mark scheme rewarded students who appreciated that farming practices improve primary production. The better students made the connection and scored well but the weaker students made bland references to photosynthesis or made vague references to farming intensity. Student understanding of selective breeding in part (ii) was impressive with many appreciating that human involvement is part of the process. In part (d), many students had no understanding of how to use quadrats. Students who were familiar with the technique scored at least two marks for mentioning the importance of random sampling and repeats. The question asked for an estimate of biomass not numbers but most students referred to counting plants rather than weighing them. Q2. This question described an investigation using a trap to compare organisms caught during the day with organisms caught at night. In parts (a) and (b) candidates needed to count the organisms and complete a tally chart and then use this data to plot a bar chart. Most candidates were able to this and scored well. The most common errors occurred in the bar chart with candidates only plotting data from nigh time or not labelling the y axis on their chart. For part (c) (i) candidates needed to compare the data for day and night. Some did this well but others merely repeated the data from the table such as 7 woodlice in the day and 15 at night. Very few gained full marks in (ii) for explaining the changes in the number of woodlice. In part (d) only the best candidates could explain how the organisms could have preyed on each other, escaped from the trap reducing the number, or bred to increase the number. In part (e) most candidates could explain what a 'habitat' is but did much less well on 'population' and 'community'.

9 Q1.

10 Q2.

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