The photograph shows one example animal taken from each of the five groups of vertebrates, and the table underneath compares the same five groups. All of th...
Question 1 Report
The photograph shows one example animal taken from each of the five groups of vertebrates, and the table underneath compares the same five groups. All of these animals have a backbone, but the groups differ from one another in several ways. The table records the kind of covering found on the outside of the body, the organ that the adult animal uses for gas exchange, the type of egg that is produced, and the way in which the body temperature is controlled. Biologists use features of this kind to place an unknown vertebrate into the correct group.
| Feature | Fish | Amphibian | Reptile | Bird | Mammal |
|---|---|---|---|---|---|
| Body covering | wet scales | moist skin | dry scales | feathers | hair / fur |
| Gas exchange (adult) | gills | lungs and skin | lungs | lungs | lungs |
| Eggs | soft, laid in water | soft, laid in water | leathery shell, on land | hard shell, on land | develop inside female |
| Body temperature | ectothermic | ectothermic | ectothermic | endothermic | endothermic |
(a) State the type of body covering found on a bird. [1]
(b) State one feature, shown in the table, that distinguishes a mammal from a reptile. [1]
(c) Describe three ways in which a fish is adapted to life in water. [3]
(d) Explain why reptile eggs can survive on dry land but the eggs of most fish and amphibians cannot. [3]
(e) State the meaning of the term endothermic. [2]
(f) Suggest one advantage to a mammal of allowing its young to develop inside the body. [2]
Answer Details
Labelled answer diagram:
(a) Body covering of a bird [1]
Feathers.
(b) One feature distinguishing a mammal from a reptile [1, max 1]
Any one from the table: a mammal has hair / fur whereas a reptile has dry scales; or a mammal is endothermic whereas a reptile is ectothermic; or a mammal's young develop inside the female whereas a reptile lays eggs.
(c) Three adaptations of a fish to life in water [3, max 3]
Any three of: gills to obtain (dissolved) oxygen from the water [1]; a streamlined body and scales to reduce resistance to movement through water [1]; fins for movement and steering [1]; large numbers of eggs fertilised externally in the water [1].
(d) Why reptile eggs survive on dry land but most fish and amphibian eggs cannot [3]
Reptile eggs have a waterproof, leathery shell that stops the egg drying out in air on land [1]; fish and amphibian eggs have no shell, only a soft jelly coat, so they lose water and dry out in air [1]; also, fertilisation in fish and amphibians is external and needs water, which land does not provide [1].
(e) Meaning of endothermic [2]
An endothermic animal keeps its internal body temperature (almost) constant [1]; independent of the temperature of its surroundings [1].
(f) One advantage of young developing inside the body [2, max 2]
The young are protected inside the mother's body [1]; and are kept warm and supplied with food and oxygen, improving their chance of survival [1].
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