UNIT 3 BIOLOGY BOOK 1 Unit 3 Biology Study Design 2006-2016 Page 1 Unit 3: Signatures of Life Page 3 Area of Study 1: Molecules of Life Page 9 Conducting Controlled Experiments Page 9 The Practical Report Page 11 Safe Practice Page 17 Major Molecules in Organisms Page 22 Water Page 22 Organisation of Life Page 25 Organic Molecules Page 25 Properties of Major Types of Macromolecules Page 26 Condensation and Hydrolysis Reactions Page 27 Carbohydrates Page 28 Lipids Page 33 Fatty Acids Page 34 Triglycerides Page 35 Trans Fats and Premature Death Page 36 Phospholipids Page 38 Fluidity of Membranes Page 39 Waxes Page 39 Steroids Page 40 Glycolipids Page 41 Proteins Page 42 Protein Structure Page 42 Different Levels of Protein Structure Page 45 Globular and Fibrous Proteins Page 48 Functions of Proteins Page 49 Nucleic Acids Page 50 DNA Page 50 Genes Page 55 RNA Page 55 Synthesis of DNA Page 56 The Roles of DNA and RNA in Protein Synthesis Page 57 Transcription Page 57 Three-Base Sequence Terminology Page 58 Translation Page 59 The Effect of Mutations on Proteins Page 64 Proteomics Page 65
Cell Theory Page 73 Cells Page 74 Cell Size Page 76 Microscopes Page 77 Prokaryotic Cells Page 79 Eukaryotic Cells Page 80 The Five Kingdoms Page 81 Organelles Page 83 Cytoplasmic Streaming Page 91 Cell Connections Page 92 Example of an Animal Cell Page 94 Example of a Plant Cell Page 95 The Cell Factory Flow Chart Page 96 Plant Cells vs. Animal Cells Page 96 Cell Specialisation/Differentiation Page 97 Cell Reproduction (Binary Fission and Mitosis) Page 99 Structure of Cell Membranes Page 109 Fluid Mosaic Model Page 109 Movement of Substances Across Membranes Page 110 Movement of Substances In and Out of Cells Page 111 Diffusion Page 111 Osmosis Page 111 Facilitated Diffusion Page 114 Active Transport Page 115 Larger Molecules and the Cell Membrane Page 116 Surface Area to Volume Ratio Page 125 Enzymes Page 139 Endergonic (Anabolic) and Exergonic (Catabolic) Reactions Page 140 Enzyme Action Induced Fit or Lock and Key? Page 141 Activation Energy Page 142 Factors Affecting Enzyme Function Page 143 Human Use of Enzymes Page 147 A Reminder About Catabolic and Anabolic Reactions Page 163 Acquiring Nutrients Page 164 Cellular Respiration Page 165 Mitochondria Page 165 Energy Page 166 Aerobic Respiration Page 168 Cellular Respiration Overview Page 169 Glycolysis Page 170 Krebs Cycle Page 170 Electron Transport Page 171 Summary Page 172 Anaerobic Respiration Page 173 Aerobic versus Anaerobic Respiration Page 174 Roles of Catabolic and Anabolic Reactions in Respiration Page 175
Photosynthesis (Endergonic Reaction) Page 176 Absorption of Light by Chlorophylls and Other Pigments Page 177 Chloroplasts Page 179 Light Dependant and Light Independent Reactions Page 181 Photosynthesis and Respiration Page 183 References Used in Compiling This Booklet Page 219 Solutions
EDITORIAL NOTE Some of the content of the TSFX Biology booklets is additional to the core material specifically outlined in the unit being examined. Exposure to some of this material would have occurred during completion of Units 1 and 2 Biology, and knowledge and understanding of these areas is still required for successful completion of Units 3 and 4. Other material includes examples of concepts, the specific content of which is not required by students. In either case, such material is denoted with an asterisk (*) throughout the booklets.
BIOLOGY STUDY DESIGN 2006 2016 SATISFACTORY COMPLETION OF BIOLOGY FROM THE VCAA Satisfactory completion of Biology is based on a decision that the student has demonstrated achievement of the set outcomes. This decision will be based on the teacher s assessment of the student s performance on assessment tasks. Schools will report a result for each unit to the Victorian Curriculum and Assessment Authority as S (Satisfactory) or N (Not Satisfactory). Completion of a unit will be reported on the Statement of Results issued by the Victorian Curriculum and Assessment Authority as S (Satisfactory) or N (Not Satisfactory). AUTHENTICATION Work related to the outcomes will be accepted only if the teacher can attest that, to the best of their knowledge, all unacknowledged work is the student s own. To achieve an outcome the student must: Produce work that meets the required standard. Submit work on time. Submit work that is clearly their own. Observe VCAA and school rules relating to VCE. UNITS 3 AND 4 In Biology the student s level of achievement will be determined by school-assessed coursework and an end-of-year examination. The VCAA will report the student s performance on each assessment component as a grade from A+ to E or UG. To receive a Study Score, students must achieve two or more graded assessments and receive S for both Units 3 and 4. The Study Score is reported on a scale of 0 50. It measures how well a student has performed in relation to all others who undertook Biology in 2016. Percentage contributions to the Study Score in Biology are as follows: Unit 3 school-assessed coursework: 20 per cent Unit 4 school-assessed coursework: 20 per cent End-of-year examination: 60 per cent The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 1
The following table shows the approximate proportion of students who will achieve a Study Score higher than the stated values. For studies with fewer enrolments, the proportions may vary slightly. Study Score (Relative Position) Percentage of students above this position (approximate) 45 2 40 8 (6% between 40-45) 35 24 (16% between 35-40) 30 50 (26% between 30-35) 25 76 (26% between 25-30) 20 92 (16% between 20-25) Your school will specify the work that you must do in Biology to satisfy the unit and the conditions under which the work is to be done. Your school must inform each student in writing of: All work needed to be achieved in order to obtain an S for the unit. All work needed to be achieved in order to receive a Graded Assessment. Class attendance requirements. How to submit work. Timelines and deadlines for completing set work. The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 2
UNIT 3: SIGNATURES OF LIFE In this unit, students consider the molecules and biochemical processes that are indicators of life. They investigate the synthesis of biomacromolecules that are common to autotrophic and heterotrophic life forms. Students consider the universality of DNA and investigate its structure; the genes of an organism, as functional units of DNA and code for the production of a diverse range of proteins in an organism. Students investigate the significant role of proteins in cell functioning; how technological advances have enabled scientists to determine differences in the molecular structure of proteins, how the structure of a protein relates to its function in an organism s tissues, and how technological advances have given rise to applications such as the design of proteins for specific purposes. Students consider advances in proteomics applied, for example, to medical diagnosis. Students investigate how cells communicate with each other at molecular level in regulating cellular activities; how they recognise self and non-self in detecting possible agents of attack; and how physical barriers and immune responses can protect the organism against pathogens. Students consider the technological advances that have contributed to our knowledge and understanding of molecular biology and thereby appreciate the dynamic nature of science. Students apply concepts related to the structure, function, activities, needs and regulated death of cells. AREA OF STUDY 1 MOLECULES OF LIFE In this area of study, students investigate the activities of cells at a molecular level; the synthesis of biomacromolecules that form components of cells and the role of enzymes in catalysing biochemical processes. Students investigate energy transformations in cells and how autotrophs and heterotrophs obtain their energy requirements, particularly through the processes of photosynthesis and cellular respiration. Students gain an understanding that DNA and proteins are the key molecules of life forms, and that DNA codes for the production of proteins. Students explore applications of molecular biology in medical diagnosis. Students undertake practical investigations into the molecular composition of cells and biochemical processes including transformation of energy and enzyme activity. Outcome 1 On completion of this unit the student should be able to analyse and evaluate evidence from practical investigations related to biochemical processes. To achieve this outcome the student will draw on key knowledge outlined in Area of Study 1, and key skills listed on page 12 of the study design. The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 3
Key Knowledge The nature and importance of biomacromolecules in the chemistry of the cell: Synthesis of biomacromolecules through the condensation reaction. Lipids and their sub-units; the role of lipids in the plasma membrane. Examples of polysaccharides and their glucose monomer. Structure and function of DNA and RNA, their monomers, and complementary base pairing. The nature of the proteome; the functional diversity of proteins; the structure of proteins in terms of primary, secondary, tertiary and quaternary levels of organisation. The structure and function of the plasma membrane and the movement of substances across it: The fluid-mosaic model of a plasma membrane. The packaging, transport, import and export of biomacromolecules (specifically protein). The role played by organelles including ribosomes, endoplasmic reticulum, Golgi apparatus and associated vesicles in the export of proteins. The nature of biochemical processes within cells: Catabolic and anabolic reactions in terms of reactions that release or require energy. The role of enzymes as protein catalysts, their mode of action and the inhibition of the action of enzymes both naturally and by rational drug design. The role of ATP and ADP in energy transformations. Requirements for photosynthesis excluding differences between CAM, C3 and C4 plants including: the structure and function of the chloroplast; the main inputs and outputs of the light dependent and light independent stages. Requirements for aerobic and anaerobic cellular respiration; the location, and main inputs and outputs, of glycolysis; the structure of the mitochondrion and its function in aerobic cellular respiration including main inputs and outputs of the Krebs Cycle and the electron transport chain. The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 4
AREA OF STUDY 2 DETECTING AND RESPONDING This area of study focuses on how cells detect biomolecules that elicit particular responses depending on whether the molecules are self or non-self. Students investigate how signalling molecules, such as hormones and neurotransmitters, assist in coordinating and regulating cell activities by binding to specific receptors on membranes of target cells, initiating a series of molecular changes in response (signal transduction). Students examine the barriers and mechanisms of organisms that protect them from invasion and infection by pathogenic organisms. They investigate mechanisms that control the effectiveness of pathogens and specific and non-specific immune responses of organisms to antigens. Students investigate signalling molecules and their role in regulating activities of organisms such as growth hormones in plants and/or action of antibiotics. They investigate how advances in molecular biology have helped to find causes of disorders in cell communication, and how technologies assist in managing disorders that interfere with coordination and regulation. Outcome 2 On completion of this unit the student should be able to describe and explain the use of the stimulus-response model in coordination and regulation and how components of the human immune system respond to the antigens and provide immunity. To achieve this outcome the student will draw on key knowledge outlined in Area of Study 2, and key skills listed on page 12 of the study design. Key Knowledge Coordination and regulation at the cellular level: The nature of the stimulus-response model and the roles of the nerve pathway and chemical signals in the transmission of information from receptor to effector. Types of signalling molecules: neurotransmitters; animal hormones; pheromones; plant growth regulators. A generalised view of how information received by a cell s receptor is transducted to an effector to initiate various cellular responses including the position of receptors for protein-based and lipid-based signalling molecules. Apoptosis (regulated cell death) as an example of cellular response to specific signals. The role of the human immune system in detecting and responding to antigens: The nature of antigens and their sources: self and non-self, and cellular pathogens and non-cellular agents (viruses and prions). The nature of physical and chemical barriers in plants and animals (including humans) to invading pathogens. The structure and role of the lymphatic system in the innate and adaptive immune response. The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 5
The nature, characteristics and roles of components in the innate (non-specific) immune response including the inflammatory response. The nature, characteristics and components of the adaptive immune response including the role and actions of B cells and their antibodies in humoral immunity and the role and actions of T helper cells and T cytotoxic cells in cell-mediated immunity. Disorders of the human immune response including the allergic response and autoimmune diseases. Acquired immunity through natural and passive strategies, including the nature and production of vaccines and antibody serums and their importance in maintaining immunity for a particular disease in the human population. ASSESSMENT OF LEVELS OF ACHIEVEMENT The student s level of achievement in Unit 3 will be determined by School-Assessed Coursework and an end-of-year examination. Contribution to final assessment School-Assessed Coursework for Unit 3 will contribute 20 percent to the Study Score. The level of achievement for Units 3 and 4 is also assessed by an end-of-year examination, which will contribute 60 percent to the Study Score. School-Assessed Coursework Teachers will provide to the Victorian Curriculum and Assessment Authority a score representing an assessment of the student s level of achievement. The score must be based on the teacher s rating of performance of each student on the tasks set out in the following table and in accordance with an assessment handbook published by the Victorian Curriculum and Assessment Authority. The assessment handbook also includes advice on the assessment tasks and performance descriptors for assessment. Assessment tasks must be a part of the regular teaching and learning program and must not unduly add to the workload associated with that program. They must be completed mainly in class and within a limited timeframe. Where optional assessment tasks are used, teachers must ensure that they are comparable in scope and demand. Teachers should select a variety of assessment tasks for their program to reflect the key knowledge and skills being assessed and to provide for different learning styles. School-Assessed Coursework in Biology includes assessment of laboratory/practical work. Students should maintain records of their work. As a guide, between 10 and 15 hours of class time should be devoted to student laboratory/practical work. The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 6
Outcomes Marks Allocated Assessment Tasks Outcome 1 Analyse and evaluate evidence from practical investigations related to biochemical processes. Outcome 2 Describe and explain the use of the stimulus-response model in coordination and regulation and how components of the human immune system respond to antigens and provide immunity. 50 25 25 Reports of three practical activities: An investigation of cellular respiration or photosynthesis An investigation of enzyme action An investigation of the movement of substances across membranes A report of an investigation or simulation of a selected organism s response to a specific chemical or physical signal AND A response to an issue or an aspect related to the immune response using any one or a combination of the following: Evaluation of research Data analysis Essay Annotated poster Media response Oral presentation using two or more data types Multimedia presentation Test Visual presentation Total marks 100 *School-Assessed Coursework for Unit 3 contributes 20 percent to the Study Score. The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 7
SAMPLE OF HOW AN OUTCOME CAN BE ASSESSED FOR A PRACTICAL ACTIVITY Outcome Descriptors/Key Knowledge & Skills Very High (5) Comprehensive understanding, detailed and accurate. High (4) Thorough understanding, detailed and accurate. Medium (3) Mostly accurate. Low (2) Some relevant discussion, understanding. Some accuracy. Very Low (1) Some reference, little understanding. Some parts incomplete and inaccurate. Not Shown (0) Understanding of the theory of the prac. Understanding of aims, hypothesis and method. Collection and presentation of results. Evaluation of procedures and results e.g. conclusions from results obtained. Application of theory. Detailed understanding. Thorough understanding. Mostly accurate. Some relevant discussion. Hypothesis clearly shows the relationship between the variables and the predicted results. Procedures are listed in clear steps. E.g. numbered, logical, in succinct order and in complete sentences. Professional looking and accurate representation of the data in tables and/or graphs. Graphs and tables are labelled and titled. Comprehensive interpretation and evaluation. Comprehensive, detailed and directly relevant. Hypothesis reasonably shows the relationship between the variables and the predicted results. Procedures are listed in a logical order; steps are numbered but not in complete sentences or clearly written. Accurate representation of the data in tables and/or graphs. Graphs and tables are labelled and titled. Possible one aspect missing. Well-developed or thorough evaluation and interpretation. Thorough, detailed and relevant. Hypothesis reasonably shows the relationship between the variables and the predicted results. Procedures are not listed in a logical order, steps are not numbered and not in complete sentences. Accurate representations of the data in written form, but no graphs or tables are presented. Relevant or mostly accurate evaluation and interpretation. Mostly accurate, detailed and related indirectly. Hypothesis has been stated but flawed in the way it explains the relationship between the variables and the predicted results. Procedures listed are difficult to follow. Some knowledge and understanding of the results. Some accuracy. Some accuracy in evaluation and interpretation. Some knowledge of terms, concepts and relationships. Some accuracy. Some reference to but little or no discussion. Hypothesis has been stated but not relevant. Procedures do not accurately list the steps of the experiment. Results identified but incomplete and inaccurate. Poor evaluation and interpretation. Incomplete or inaccurate. Knowledge unclear, irrelevant, incomplete or inaccurate. Outstanding Excellent Very good Good Satisfactory 22.5-25 20-22 17.5 19.5 15 17 12.5 14.5 Meets minimum standard 10-12 Unsatisfactory <10 Overall SAC Grade: /25 The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 8
AREA OF STUDY 1 MOLECULES OF LIFE CONDUCTING CONTROLLED EXPERIMENTS Scientific experiments are conducted following certain procedures to ensure the results are valid. An observation is made: (E.g. Food scraps on the school oval tend to remain for a longer period of time than those left in the school garden.) Hypothesis: A hypothesis can be created to explain the observation. A hypothesis is a predictive statement or educated guess (not a question) that accounts for the observation. It can be tested by using data from a controlled experiment. (E.g. The population of invertebrates in the school garden is greater than that of the school oval.) Note: Whether the hypothesis ends up being supported or disproven by the experimental results is unimportant! Controlled Experiment: A controlled experiment involves two set ups which are the same in every respect except for the variable being tested (experimental variable). All other variables must be identical between the two set ups (controlled or constant variables). Hence, any difference in results can validly be attributed to the experimental variable. (E.g. On a particular evening, one petri dish with 5 grams of grated carrot is placed in the garden and an identical set up is placed on the oval.) In one set up, called the control (it s really a comparison set up), all variables are kept constant (controlled) while in the other set up one factor (in this case location of the petri dish) is varied. The validity of the results will be further increased if the experiment is conducted repeatedly. That is, that the experiment is repeated more than 5 times. (i.e. Distribute petri dishes on a variety of evenings and in a variety of oval and garden locations.) This reduces the chance of sampling errors having a significant effect on the results. Errors in technique are not as easily exposed by simply using repeats, unless on subsequent occasions, maybe involving another experimenter, similar results cannot be gained after repeating the same task. The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 9
Hence, in a typical controlled experiment the following factors should exist: 1. Two set ups are made: The experimental set up and the control set up. 2. All variables between the two set ups are controlled except one. 3. Repeats of the experiment, i.e. more than five repeats. Results: Data collected can be qualitative (without accurate measurements) or quantitative. Where possible, quantitative data is preferable, and care must be given to using correct units of measurement. (E.g. The mass of grated carrot is measured before and after 10 hours of overnight exposure on the oval and in the garden.) The arrangement and appearance of results should be easy to understand. Using a table or a graph to represent your results is preferable to simply writing notes. All relevant units must be noted. Analysis and Interpretation of Results: Data is translated or explained. Evidence from the results is used to obtain some certainty for any arguments made. (E.g. If significant quantities of grated carrot disappeared from garden petri dishes, while most remained in the dishes placed on the oval, one might use this evidence to explain the disappearance of grated carrot in terms of differences in invertebrate numbers at the two sites.) Conclusion: A final opinion is made in relation to the hypothesis made at the beginning of the activity. A hypothesis can be supported or disproven, but never proven! (E.g. Evidence from this activity supports the hypothesis that the population of invertebrates in the school garden is greater than that of the school oval.) The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 10
THE PRACTICAL REPORT A report of your investigation could be presented in the following manner: Aim: A clear statement outlining the purpose of the experiment. Hypothesis: As outlined above. Materials and Method: If the activity is prescribed in a text, reference to the text and its relevant pages is all that is required. (e.g. As outlined in The Joy of Invertebrate Investigations, pp44-6 ) If, however, the activity is of your design, all apparatus and materials should be listed. Then the procedure should also be set out in step by step point form. Results: As indicated earlier, results are ideally presented in a: (i) (ii) Graph or Table format For example: Invertebrate Consumption of Carrot at Aphid SC Mass of Carrot Remaining after 10 Hours (g) 6 5 4 3 2 1 0 Garden Oval Every graph should have a title and labelled axes, with units noted. If relevant, any additional observations can be made in the results section. Any explanations of the results, however, should be made in the Analysing Results (Discussion) section. The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 11
Discussion: All analysis and interpretation of the data occurs here. In addition, deductions could be noted from the results which could then be applied to new investigations. Evaluation of the experimental procedure could be highly relevant to the experimental outcome, and if so should be discussed. Conclusion: As indicated earlier, a final opinion is made in relation to the hypothesis outlined at the beginning of the activity. Do the results support or disprove the hypothesis, or are further investigations necessary in light of the results before such a statement can be made? QUESTION 1 A student noticed that the tips of wheat seedlings always bent towards the light (phototropism). She set up an experiment to determine if some colours (wavelengths) of light influenced the bending of shoot tips more than others. The student performed the following procedure: Four identical petri dishes (A-D) were collected and each filled with 1 cm of moist potting mix. Two wheat seedlings (2-3 cm in height) were planted in each dish and watered. Each dish was covered with an upside down black polystyrene cup. A slit extending one third of the cup s circumference (to allow entry of light) was present in each cup. Each dish was exposed to the following light sources for two hours: Dish A White light Dish B Red light (light covered in red cellophane) Dish C Green light (light covered in green cellophane) Dish D Blue light (light covered in blue cellophane) After two hours, the angle shoot tip curvature was recorded. Evaluate this experiment, noting both the good aspects of the experimental design as well as any possible areas for improvement if the experiment was to be repeated. Good Aspects Areas For Improvement The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 12
QUESTION 2 Stony corals are small animals that live in cups of calcium carbonate that they have deposited. Colonies of these animals are responsible for building the large calcium carbonate formations known as coral reefs. The cells lining the pharynx of most reef-building corals are known to contain algae. A researcher performed the following experiment in which the importance of algae and light to the rate of calcium carbonate deposition were determined. (Note that algae can be removed without damage to the corals.) One day later equal amounts of a solution containing radioactive calcium ions were added to the seawater around each of the corals. A week later the rate at which radioactive calcium had been deposited as calcium carbonate was measured with the following results: Rate of calcium deposition (micrograms of calcium per hour) by corals With Algae Without Algae Light Dark Light Dark 1.63 0.81 0.26 0.26 The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 13
State whether or not the results support each of the following hypotheses. Give a reason for each answer. (a) (i) In the absence of algae, light increases the rate of calcium deposition by corals. Answer Reason (ii) The presence of algae increases the rate of calcium carbonate deposition by corals in the light. Answer Reason (iii) The presence of algae has no effect on calcium carbonate deposition in the dark. Answer Reason 3 marks (b) (c) Suggest a hypothesis that explains the combined effect of light and the presence of algae on the rate of calcium carbonate deposition by corals. Explain how scientists ensured that this experiment on stony corals was controlled. 1 mark 3 marks Total 7 marks The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 14
QUESTION 3 Guppies (Poecilia reticulata) are common aquarium fish that are native to Central and South America. Males exhibit a variable number of brightly coloured spots. The number of spots in males is genetically determined. Wild populations differ in the average number of spots. A researcher performed the experiments described below, to test the hypothesis that natural selection is responsible for the differences in the average number of spots among wild populations. Experiment 1 Female guppies choose a mate on the basis of the number of spots. To determine the effect of female mate choice on the average number of spots in male populations, guppies were placed in artificial ponds approximating their natural habitat. The populations were started with equal numbers of each phenotype. Over several generations, the fish were sampled and the average number of spots per male determined. The results are shown in the graph below. (a) (b) Based on the results shown in the graph, what trend was observed in the average number of spots in males over the course of the experiment? Describe how Experiment 1 was controlled. 1 mark 2 marks The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 15
In some natural ponds, a fish species occurs which preys almost exclusively on guppies (Predator X). In other ponds, a different fish predator occurs which feeds only rarely on guppies (Predator Y). The researcher hypothesised that large numbers of spots might make male guppies more obvious to these predators. The following experiment was performed to test this hypothesis. Experiment 2 Initial populations of guppies, as described in Experiment 1, were placed in artificial ponds. Predator X was added to some of the ponds, while Predator Y was added to others. No predators were added to a third group of ponds, as in Experiment 1. Guppies were collected over several generations, the numbers of spots on males were recorded, and all fish returned to the ponds. The results are shown in the graph below. (c) (d) (e) Based on the results shown in the graph, what trend was observed in the average number of spots per male over the course of the experiment when Predator X was present in the ponds? List the factors which ensured Experiment 2 was controlled. 1 mark 2 marks What can you conclude about the final effect of Predator Y on the average number of spots per male? 1 mark The School For Excellence 2016 Unit 3 Master Classes Biology Book 1 Page 16