The photograph shows five vertebrates, labelled P to T: P a bony fish, Q a frog, R a lizard, S a pigeon and T a rabbit. (a) State the internal feature, comm...
Question 1 Report
The photograph shows five vertebrates, labelled P to T: P a bony fish, Q a frog, R a lizard, S a pigeon and T a rabbit.
(a) State the internal feature, common to all five animals, that identifies them as vertebrates. [1]
(b) State two features, visible in the photograph, that identify animal P as a fish. [2]
(c) State two external features that distinguish animal T (a mammal) from animal S (a bird). [2]
(d) Explain how feathers help animal S to keep a constant body temperature. [2]
(e) The body temperature of animal R changes with its surroundings. State the term used to describe this. [1]
(f) Animal R basks in the sun each morning. Explain how basking helps it to become active. [3]
Answer Details
This question tests the features used to classify the five vertebrate groups (fish, amphibian, reptile, bird, mammal).
(a) The internal feature common to all five is a backbone / vertebral column (they are vertebrates because they have an internal bony spine) [1].
(b) Any two visible features identifying P as a fish (max 2): wet / moist scales; fins; and gills (gill covers) [2, 1 each].
(c) Any two external features distinguishing the mammal (T) from the bird (S), max 2: the mammal has hair / fur whereas the bird has feathers; and the mammal has external ears (pinnae) whereas the bird has none (accept mammal has no beak / bird has a beak) [2, 1 each].
(d) Feathers help keep a constant body temperature because they trap a layer of air next to the skin [1], and since air is a poor conductor (a good insulator), heat loss from the body is reduced [1]. [2]
(e) An animal whose body temperature changes with its surroundings is described as ectothermic (accept cold-blooded / poikilothermic) [1].
(f) Basking helps the lizard become active because the Sun's warmth raises its body temperature [1]; this makes its enzymes work faster / nearer their optimum temperature [1], so respiration releases energy more quickly for movement [1]. [3]
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