© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.2 Questions and answers 1 1a. What is a backbone? A:A series of bones that run along the back of some animals. b What is its purpose? A:Supports the animal and protects the spinal cord. 2Explain why the duck-billed platypus is a chordate. A:It has a spinal cord.

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.2 Questions and answers 2 3State one feature that members of the following groups of animals all have in common: a chordates A:All have spinal cords. b vertebrates A:All have backbones (that protect the spinal cord). Accept other correct answers, such as internal skeleton. B1.2 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.2 Questions and answers 3 4Describe three ways in which different vertebrates get oxygen from the environment into their body. A:Using lungs, using gills, through moist skin. B1.2 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.2 Questions and answers 4 5a How are reptiles and birds similar? A:Two (or more) from: breathe using lungs, vertebrates, lay eggs, internal fertilisation. b How are reptiles and birds different? A:Birds have feathers, birds are homeotherms. B1.2 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.2 Questions and answers 6Which characteristic separates birds and mammals from the other vertebrates? A:They are both homeotherms. 5

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.2 Questions and answers 7Construct an argument for classifying an axolotl as a fish. A:Has gills as an adult, spends all its time underwater and is poikilothermic. Despite the fact that it has limbs (counterargument) only fish have all those three characteristics. 6

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.2 Questions and answers 8Explain why it was difficult to classify the platypus as a mammal, and suggest how scientists finally made that decision. A:A good answer will contain the following points: platypuses are like reptiles because they lay leathery eggs they are like reptiles because they have a skeleton structure/body shape that is like a lizard’s they are like birds because they have a beak like all mammals it has hair like all mammals it produces milk (although, as a point on interest, it doesn’t have nipples) © Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 7

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.2 Questions and answers all mammals produce eggs, it’s just that the eggs tend to stay inside the female to develop They bear more similarities with mammals than with any of the other groups (some students might suggest that DNA testing would show their similarity to other mammals and this should also be given credit, even though DNA analysis was invented long after the classification of platypuses as mammals). © Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 8