1Cut out the Animals Divide Them Into Chordates and Non-Chordates

Organisms are sorted into kingdoms. The members of those kingdoms are sorted into further groups.

1Cut out the animals divide them into chordates and non-chordates.

2Divide the chordates into homeotherms and poikilotherms.

3Divide both your groups in question 2 into more, smaller groups. Start with internal and external fertilisation. Then divide each of those groups into animals that are viviparous and those that are oviparous. Finally divide all these groups into animals that have lungs, those that get oxygen through their skin and those that have gills. Think up a name for each of your groups.

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1Find out and fill in the common names of the vertebrates in the table.

2Decide which vertebrate group each animal belongs to and add this information to your table.

3Carry out research to identify the animals that do not have all the usual features common to other animals in their group.

Scientific name / Common name / Vertebrate group
Ailurus fulgens
Ambystoma mexicanum
Cryptobranchus alleganiensis
Daubentonia madagascariensis
Epipedobates tricolor
Megadyptes antipodes
Oncorhynchus nerka
Pelochelys cantorii
Strigops habroptila
Zaglossus bruijni

Two animals that have features unusual for their vertebrate group are Ambystoma mexicanum (an amphibian that has gills in the adult) and Zaglossus bruijni (a mammal that lays eggs).

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You do not need to remember the details on this sheet for your exam but you could be asked to apply your knowledge to unfamiliar situations.

1Scientists sometimes discover new animals or the fossils of animals that died out a long time ago. They need to classify them. The drawing shows a fossil of a Tiktaalik, a creature that died out about 380 million years ago.

aIs the Tiktaalik a vertebrate or an invertebrate? Explain your answer. [2]

bWhich labels (A–G) show evidence that the animal was a fish? [2]

cWhich labels (A–G) show evidence that the animal was an amphibian? [2]

2Scientists have discovered another fossil dating from 121 million years ago. They have called it Sinosauropteryx. It could be a bird or it could be a reptile. Suggest one piece of evidence that scientists would look for to answer this question and explain why this evidence would be useful.

3Duck-billed platypuses lay eggs with leathery shells and they have fur.

aWhy did these two features make it difficult for scientists a hundred years ago to decide what vertebrate group to put them in? [2]

bDuck-billed platypuses have the scientific name Ornithorhynchus anatinus. These two words are the names of two of the groups in which platypuses are found. Which two? (Hint: Think about classification.) [1]

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The drawings show various creatures from myths and legends.

Scientists realised that these creatures could not exist because they did not fit into any system of animal classification.

1aIf they existed, which of the creatures would be poikilothermic. Explain your choices.

bIf they existed, which of the creatures would lay eggs. Explain your choices.

2 aImagine that these creatures do exist. Design a system of classification for them so that each creature eventually ends up in a group of its own. You could display your work as a spider diagram. The group at the top of the diagram would contain all the creatures. Spider diagrams look like this:

bGive each of the groups in your classification system a name.

c All of the mythical creatures appear to be chordates. What is a chordate?

3This is a mythical sea-lion.

aUse your classification system to classify this creature as best you can.

bDescribe how well your classification system worked in classifying this creature. Are there any alterations that you would like to make to your system? If so, what are they?

cWhy do you think some parts of classification systems used by biologists change quite frequently?

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