AS Level Biology A ., Exams of Biology

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…day June 20XX – Morning/Afternoon

AS Level Biology A. H020/02 Depth in biology PRACTICE MARK SCHEME Duration: 1 hour 30 minutes

MAXIMUM MARK 70

H020/

Final

This document consists of 18 pages Mark Scheme June 20XX MARKING INSTRUCTIONS PREPARATION FOR MARKING SCORIS

1. Make sure that you have accessed and completed the relevant training packages for on-screen marking: scoris assessor Online Training ; OCR Essential Guide to Marking.
2. Make sure that you have read and understood the mark scheme and the question paper for this unit. These are posted on the RM Cambridge Assessment Support Portal http://www.rm.com/support/ca
3. Log-in to scoris and mark the required number of practice responses (“scripts”) and the required number of standardisation responses. YOU MUST MARK 10 PRACTICE AND 10 STANDARDISATION RESPONSES BEFORE YOU CAN BE APPROVED TO MARK LIVE SCRIPTS.

H020/

Note: Award 0 marks – for an attempt that earns no credit (including copying out the question).

8. The scoris comments box is used by your Team Leader to explain the marking of the practice responses. Please refer to these comments when checking your practice responses. Do not use the comments box for any other reason. If you have any questions or comments for your Team Leader, use the phone, the scoris messaging system, or email.
9. Assistant Examiners will send a brief report on the performance of candidates to their Team Leader (Supervisor) via email by the end of the marking period. The report should contain notes on particular strengths displayed as well as common errors or weaknesses. Constructive criticism of the question paper/mark scheme is also appreciated. 3

H020/02 June 20XX Mark Scheme

10. For answers marked by levels of response: Read through the whole answer from start to finish, concentrating on features that make it a stronger or weaker answer using the indicative scientific content as guidance. The indicative scientific content indicates the expected parameters for candidates’ answers, but be prepared to recognise and credit unexpected approaches where they show relevance. Using a ‘best-fit’ approach based on the science content of the answer, first decide which set of level descriptors, Level 1, Level 2 or Level 3, best describes the overall quality of the answer using the guidelines described in the level descriptors in the mark scheme. Once the level is located, award the higher or lower mark. The higher mark should be awarded where the level descriptor has been evidenced and all aspects of the communication statement (in italics) have been met. The lower mark should be awarded where the level descriptor has been evidenced but aspects of the communication statement (in italics) are missing. In summary:
    • The science content determines the level.
    • The communication statement determines the mark within a level. Level of response questions on this paper are 2(c) and 3(b)(ii). H020/02 Mark Scheme June 20XX
    11. Annotations Annotation Meaning

Your first task as an Examiner is to become thoroughly familiar with the material on which the examination depends. This material includes:

• the specification, especially the assessment objectives
• the question paper
• the mark scheme. You should ensure that you have copies of these materials. You should ensure also that you are familiar with the administrative procedures related to the marking process. These are set out in the OCR booklet Instructions for Examiners. If you are examining for the first time, please read carefully Appendix 5 Introduction to Script Marking: Notes for New Examiners. Please ask for help or guidance whenever you need it. Your first point of contact is your Team Leader.

Question 1 (a) (i) Answer Marks Guidance fossils  idea that fossils deeper in the ground are older than those near the surface 

ALLOW reference to radiometric dating IGNORE refs to carbon dating as time-scale is too great (ii) Any two from similar tail segments lateral spines 

(iii) no scale given on figure  idea that comparison in absolute length cannot be made  idea that comparison in relative length (compared with body length) could be valid  maturity / age , of specimen unknown  idea that only one individual of each species observed 

(iv) adaptation and explanation must both be present to be awarded the mark tail for , swimming / movement OR segments , for flexibility / moving tail / swimming 1 ALLOW streamlined shape for movement in water

Question Question Answer Marks Guidance 2 (a) idea of more transects in different parts of area 1 and 2  (collect at) different, times of day / times of year / weather conditions  method of ensuring that individuals not counted again  (use a method to) capture individuals  (use a method to) correctly identify species 

ALLOW example of appropriate method, e.g. (butterfly) net ALLOW e.g. photograph / use of key (b) (i) (Area) 2 (because it) has , more / 6 , species 

(ii) Answer Marks Guidance (Area) 2 idea that the range of n is smaller 

ALLOW use of figures to exemplify

Question (iii) Area 1 Area 2 Species of butterfly Number of individuals ( n ) Number of individuals ( n ) n / N ( n / N )^2 Grayling (^2 5) 0.125 0. Large heath 16 10 0.250^ 0. Gatekeeper 9 7 0.175^ 0. Green hairstreak 3 5 0.125^ 0. Silver-studded blue (^0 2) 0.050 0. Small heath 8 11 0.275^ 0. Simpsons Index

N = 40 0.

any successful calculation of ( n / N )^2  (Σ( n / N )^2 =) 0.2024  (1-Σ( n / N )^2 =) 0.7976  answer given to 4 significant figures  4 Correct answer given to 4 sig. fig. with no working shown = 4 marks ALLOW correct answer with different sig. figs ALLOW correct answer with different sig. figs

Level 3 (5–6 marks) Full and detailed evaluation of the students’ conclusion taking into account the validity of the method used and the implications of the data collected. Learner demonstrates a holistic judgement of the information including evidence for and against the claim. The candidate makes a judgement that there is not enough evidence to support the students’ conclusion. There is a well-developed line of reasoning which is clear and logically structured. The information presented is relevant and substantiated. Level 2 (3–4 marks) An evaluation of the students’ conclusion taking into account the validity of the method used and/or the implications of the data collected. Learner demonstrates a holistic judgement of the information including evidence for and against the claim. The candidate makes a judgement in line with the argument they have presented. There is a line of reasoning presented with some structure. The information presented is in the most-part relevant and supported by some evidence. Level 1 (1–2 marks) An evaluation of the claim is attempted including discussion of either the validity of the method or the implications of the data. The answer includes evidence for or against the claim. A definitive judgement may not be present. A basic structure and some relevant information is provided, although a clear line of reasoning may not be present. The information is supported by limited evidence and the relationship to the evidence may not be clear. 0 marks 6 Indicative scientific points may include… Evidence to support the conclusion (that fencing increased biodiversity)

• calculated Simpson’s Index of Diversity is higher in fenced area
• high Simpson’s Index means high biodiversity
• greater number of species/ higher species richness in fenced area
• Silver-studded blue only occurs in fenced area. Students’ conclusion may be overdrawn because…
• difference in Simpson’s Index of Diversity between two areas is small (12%)
• range of number of individuals is greater in Area 1 (0 - 16) than Area 2 (2 – 11)
• Higher number of individuals of ‘Large heath’ and ‘Gatekeeper’ butterflies sighted in Area 1.
• Do not know length of time Area 2 has been fenced off.
• limitations of method o samples taken on only two days o samples only taken in one season o no method to prevent recounting o observation at a distance might have led to mis-identification.

(ii) For answers marked by levels of response: Read through the whole answer from start to finish, concentrating on features that make it a stronger or weaker answer using the indicative scientific content as guidance. The indicative scientific content indicates the expected parameters for candidates’ answers, but be prepared to recognise and credit unexpected approaches where they show relevance. Using a ‘best-fit’ approach based on the science content of the answer, first decide which set of level descriptors, Level 1, Level 2 or Level 3, best describes the overall quality of the answer using the guidelines described in the level descriptors in the mark scheme. Once the level is located, award the higher or lower mark. The higher mark should be awarded where the level descriptor has been evidenced and all aspects of the communication statement (in italics) have been met. The lower mark should be awarded where the level descriptor has been evidenced but aspects of the communication statement (in italics) are missing. In summary:

• The science content determines the level.
• The communication statement determines the mark within a level. Question Answer Marks Guidance

Level 3 (5–6 marks) Describes fully the behaviour of the chambers and valves at W , X , Y and Z , and relates these behaviours to changes in pressure, at all of points W - Z. There is a well-developed connection between the events and causes at all four points, which is clear and logically structured and uses scientific terminology at an appropriate level. Level 2 (3–4 marks) Describes the behaviour of the chambers or valves, and relates some of these behaviours to changes in pressure, at all of the points W - Z. There is a developed connection between the events and causes discussed, which is clear and logically structured and uses scientific terminology at an appropriate level. Level 1 (1–2 marks) Describes the behaviour of the chambers or valves, or describes the pressure changes, at some of points W - Z. The description provided is clear and unambiguous and uses scientific terminology at an appropriate level. 0 marks 6 Indicative scientific points may include… Chambers

• ventricles begin to contract at Y
• ventricles are relaxing between W and Y
• atria relaxed at W , X , Y and Z
• atrial contraction completed before Y. Valves
• A-V / bicuspid , valve closes at Y and opens at X
• semilunar / aortic , valve opens at Z and closes at W. Pressure
• At W ventricular pressure falls below aortic pressure
• At X ventricular pressure falls below atrial pressure
• At Y ventricular pressure rises above atrial pressure
• At Z ventricular pressure rises above aortic pressure. Question Answer Marks Guidance

(ii) limitation idea that end point is subjective / difficult to judge  improvement use of pH meter  2 ALLOW other valid limitations e.g. fat separates to top of solution ALLOW other valid improvements e.g. keep mixing throughout experiment (c) (i) formula M (no mark) because high ratio of hydrogen to oxygen / N has (approximately) 2 H to 1 O 

(ii) hydrophilic head and hydrophobic tails  hydrophobic part / tails , repelled / AW , by water head / hydrophilic part , forms H bonds with water  idea that medium outside / inside plasma membrane is aqueous  idea that hydrophobic nature of tails results in their facing towards each other 

(d) (m)RNA transported out of nucleus  (m)RNA transported to / associates with ribosome  translation / protein synthesis , occurs at ribosome  (t)RNA brings specific amino acids or (t)RNA described  peptide bonds form between adjacent amino acids or peptide bonds described  polypeptide / protein processed through Golgi apparatus 

Question Answer Marks Guidance

Total 14 Question Answer Marks Guidance 5 (a) mobile vector / insect , moving / flying from tree to tree AW  low genetic diversity / lack of resistance  fungal spores carried by the wind AW  climate favouring fungal growth / spread of vector  overcrowding of trees / small distance between trees 

(b) vector  1 ALLOW carried by insects (c) Plasmodium  Protista / Protoctista  Eukaryota / Eukarya  3 ALLOW falciparum (d) mosquito mouthparts pierce skin / AW  pathogen injected (directly) into blood 

Total 8 Question Answer Marks Guidance