Revision 7

1. Revision 7

2. Multiple choice 1 The question below relates to the diagram showing parts of a food web for a community living on or near an island off the coast of Western Australia. Which of the following statements about this community is true? a) The biomass of the spider species is less than the total biomass of the two beetle species. b) The seabirds are producers in this community. c) Saltbush plants provide the total solar energy input for the community. d) Lice are first-order consumers.

3. Multiple choice 1 The question below relates to the diagram showing parts of a food web for a community living on or near an island off the coast of Western Australia. Which of the following statements about this community is true? a) The biomass of the spider species is less than the total biomass of the two beetle species. b) The seabirds are producers in this community. c) Saltbush plants provide the total solar energy input for the community. d) Lice are first-order consumers.

4. Multiple choice 2 Which of the following statements is true of natural ecosystems? a) Energy recycles through natural ecosystems. b) Nutrients flow through natural ecosystems. c) Natural ecosystems include living and non-living components. d) There is no heat energy loss from natural ecosystems. Use your understanding of food pyramids and biomass in balanced natural ecosystems to select the correct statement from the following. a) Because producers have the highest biomass it is unlikely that any individual plant species will be rare. b) Third order consumers will always be fewer in numbers than second order consumers. c) The higher the trophic level of a species the smaller the organism. d) The number of organisms of a particular species depends on many factors, not just its position in the food web.

5. Multiple choice 2 Which of the following statements is true of natural ecosystems? a) Energy recycles through natural ecosystems. b) Nutrients flow through natural ecosystems. c) Natural ecosystems include living and non-living components. d) There is no heat energy loss from natural ecosystems. Use your understanding of food pyramids and biomass in balanced natural ecosystems to select the correct statement from the following. a) Because producers have the highest biomass it is unlikely that any individual plant species will be rare. b) Third order consumers will always be fewer in numbers than second order consumers. c) The higher the trophic level of a species the smaller the organism. d) The number of organisms of a particular species depends on many factors, not just its position in the food web.

6. WATP short answers 1 A biologist conducted some experiments to determine patterns of inheritance in pea plants. There are two types of pods in these plants-inflated pods and constricted pods. He crossed homozygous inflated pod plants with homozygous constricted pod plants. This cross resulted in all of the F1 generation plants having inflated pods. Use a punnet square to predict the phenotypes and genotypes and their ratios in the F2 generation.

7. WATP short answers 1 A biologist conducted some experiments to determine patterns of inheritance in pea plants. There are two types of pods in these plants-inflated pods and constricted pods. He crossed homozygous inflated pod plants with homozygous constricted pod plants. This cross resulted in all of the F1 generation plants having inflated pods. Use a punnet square to predict the phenotypes and genotypes and their ratios in the F2 generation. Assume D-inflated and d-constricted.(1) P generation DD x dd  F1 generation all Dd Punnett square for F1 cross Dd x Dd (1) F2 generation Genotypes: 25% DD, 50% Dd, 25% dd. (1) Phenotypes: 75% inflated pods, 25% constricted pods.(1) D d D DD Dd d Dd dd

8. WATP short answers 2 A B C Explain whether this trait is sex-linked or autosomal, dominant or recessive. Give reasons in your answer. Explain how you could determine the genotype of individual B. What genotypes and genotypes would you expect to see from a cross between individuals A and C?

9. WATP short answers 2 A B C Explain whether this trait is sex-linked or autosomal, dominant or recessive. Give reasons in your answer. Autosomal(1)-Second generation individual IV would have the condition if it was sex linked, sex-linked conditions are always passed on from affected mother to son.(1) Recessive(1)-Second generation individuals I and II neither have condition but son does. If it were dominant, this would not be possible.(1) Explain how you could determine the genotype of individual B. A test cross can be used to determine the unknown genotype of an organism when the trait is determined by an autosomal gene.(1) You must cross the unknown individual with a homozygous recessive individual.(1) If the unknown individual was homozygous dominant then all of the offspring will have the dominant trait.(1) If the unknown individual was heterozygous then half of the offspring will be dominant and the other half will be recessive.(1) What genotypes and genotypes would you expect to see from a cross between individuals A and C? Nn x Nn  ¼ NN, ½ Nn, ¼ nn; ¾ would not show it, ¼ would

10. WATP short answers 3 a) Identify the four organelles labelled: A B C D b) Describe the function of the following organelles Golgi bodies Endoplasmic reticulum Nucleus Ribosomes c) Name one organelle that can be used to determine whether a cell is a plant or an animal

11. WATP short answers 3 a) Identify the four organelles labelled: A-Mitochondria B-Chloroplast C-Golgi Body/Apparatus D-Endoplasmic reticulum b) Describe the function of the following organelles Golgi Body-Stores, modifies and packages chemicals for export from cell Endoplasmic reticulum-Used for transport for synthesised proteins to Golgi apparatus and for additional processing of proteins as part of cell metabolism Nucleus – controls activity of cell, contains DNA which codes for protein synthesis Ribosomes – protein synthesis c) Name one organelle that can be used to determine whether a cell is a plant or an animal Plants have chloroplasts, cell wall, large vacuole, no centrioles, cilia or flagella Animals have no chloroplasts or cell wall, usually have smaller vacuoles, centrioles, and may have cilia or flagella

12. Cells A a) Below is a drawing of a cell membrane. Name the structures labeled A and B. B b) Describe the function of the i) A ii) B c) Cell membranes are differentially or semi-permeable. Define differentially or semi-permeable. d) Explain the difference between passive and active transport. Give examples of each.

13. Cells A a) Below is a drawing of a cell membrane. Name the structures labeled A and B. A = phospholipid B = protein B b) Describe the function of the i) A – waterproof, flexible layer, that lets in small particles ii) B – provides channels for larger particles (facilitated diffusions), acts as pumps (active transport), acts as receptor sites c) Cell membranes are differentially or semi-permeable. Define differentially or semi-permeable. Allows some substances through, but not others. d) Explain the difference between passive and active transport. Give examples of each. Passive – no energy required, eg osmosis, diffusion, substances move along a concentration gradient - from areas of high concentration, to areas of low concentration. Active – energy required, eg active transport, ion pumps, endocytosis, exocytosis, substances can move against a concentration gradient - from areas of low concentration, to areas of high concentration.

14. Cells 2 Sketch the appearance of each of the following cells & explain the changes that occur: Animal cell Plant cell after 30 minutes in salt water after 30 minutes in salt water Plant cell Animal cell after 30 minutes in distilled water after 30 minutes in distilled water

15. Cells 2 Sketch the appearance of each of the following cells & explain the changes that occur: Animal cell Plant cell Plasmolysis Water moves out by osmosis Vacuole shrinks, cell membrane pulls away from cell wall Water moves out by osmosis Cell membrane wrinkles as cytoplasm shrinks after 30 minutes in salt water after 30 minutes in salt water Plant cell Animal cell Turgor pressure Water moves in by osmosis Vacuole swells, cell membrane pushes up against cell wall. Cell may bulge, but resists bursting because of cell wall Water moves in by osmosis Cytoplasm swells, cell membrane bulges, and then may burst because of increased pressure after 30 minutes in distilled water after 30 minutes in distilled water

16. Extended answer 2005 36d In what ways are urban and agricultural ecosystems similar in their inputs, outputs, amount of recycling of matter and stability? In what ways do they differ? What problems might arise if human population growth is concentrated in urban ecosystems?

17. Extended answer 2005 36d In what ways are urban and agricultural ecosystems similar in their inputs, outputs, amount of recycling of matter and stability? In what ways do they differ? What problems might arise if human population growth is concentrated in urban ecosystems? 2 marks per row in the table to a maximum of 8 marks Similarities/differences Similarites Urban Agricultural • Inputs –high matter fossil fuels fossil fuels, fertilizers, sunlight • Outputs – high pollution, rubbish, heat produce, pollution • Recycling – low • Stability – low waste accumulation environmental degradation Differences • Inputs Increasing Can be reduced - sustainable practice • Outputs Increasing Can be reduced - sustainable practice PROBLEMS OF CONTINUED URBANISATION • Increased destruction of natural ecosystems (reduced habitat/ biodiversity) • Increased pollution – affects natural ecosystems (water/atmospheric pollution) • Depletion of resources – minerals, fossil fuels, lower water table • Climate change • Urban ecosystems depend on agricultural ecosystems 1 mark for each line, maximum 4 marks Maximum 10 marks total

18. Extended answer 2002 37(b) Ichthyosaurs are extinct marine animals that appear remarkably similar to a modem marine animal, the dolphin. However, ichthyosaurs were reptiles, related to snakes and lizards while dolphins are mammals related to dogs, cats and humans. Explain how two animals from such very different groups could have evolved to look so similar.

19. Extended answer 2002 37(b) Ichthyosaurs are extinct marine animals that appear remarkably similar to a modem marine animal, the dolphin. However, ichthyosaurs were reptiles, related to snakes and lizards while dolphins are mammals related to dogs, cats and humans. Explain how two animals from such very different groups could have evolved to look so similar. Similarities arise by convergent evolution • where different / unrelated taxa evolve to look similar • in response to similar selection pressures. • Example other than dolphins & ichthyosaurs • Natural selection works in populations showing variation • causing differential survival rates • and differential reproduction rates. • Results in changes to gene frequencies Sources of variation: • Crossing over • Mutation • Independent assortment • Random recombination / fertilization • Selection pressure caused by aquatic environment / predatory nature results in • streamlining • fins • rapid locomotion • large mouth for prey capture