THE FAMILY PET
CLASSIFICATION AND KEYS
STUDENT NAME: SOLUTIONS
Getting started:
In small groups, list as many animals people keep as pets. Your list
should include at least 15 animals. Then try to devise ways of splitting
this large group into smaller groups based on a single feature. Record
your answers on the following page
YOUR GROUP LIST OF PETS
Rabbit, dog, cat, goldfish, turtle, horse, canary, parrot, pig, chicken, cow,
lizard, frog, mouse, snake
TWO-GROUP CLASSIFICATION SCHEME
(feature used to group pets =……warm/cold blooded
(endothermic/ectothermic)
………………………………)
warm
cold
Rabbit, dog, cat, horse, canary,
parrot, pig, chicken, cow, mouse
Goldfish, turtle, lizard, frog, snake
THREE-GROUP CLASSIFICATION SCHEME
(feature used to group pets =……leg
number………………………………)
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4 limbs
2 legs/limbs
no legs/limbs
Rabbit, pig, cow,
horse, dog, cat,
turtle, lizard, mouse,
frog
Parrot, canary, chicken
snake, goldfish
FOUR GROUP CLASSIFICATION SCHEME
(feature used to group pets =……………………………………)
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WHY CLASSIFY LIVING THINGS?
Questions
1.
Find definitions of the terms taxonomist, biodiversity and arachnologist. You may have to use
secondary sources.
Taxonomist: a biologist who specializes in the classification of organisms into groups on the
basis of their structure and origin and behaviour.
Biodiversity: the relative abundance and variety of plant and animal species and ecosystems
within particular habitats
Arachnologist: person who studies the life cycles, behaviour, ecology, or diversity of spiders.
2.
Describe the advantage of giving each species a scientific name.
The advantage of using scientific names is that despite speaking different languages
scientists are able to easily identify an organism because the scientific name is a common
language.
3.
Find the scientific names of three common pets.
Canis familiaris (dog)
Felis domesticus (cat)
Melopsittacus undulates (budgie)
4.
What is classification?
Classification is a process in which objects or living things are sorted into groups based
upon similarities in their features (characteristics).
5.
In 100 words or less, explain why scientists classify organisms.
Scientists classify organisms to try to make their study easier and to improve their ability to
communicate with each other.
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CLASSIFICATION KEYS
Exercise 1: A dichotomous key of common pets.
Note: A dichotomous key is any type of key that is designed with only TWO
choices at each point.
1. Which pet does not live in water, does not have big
ears, does not breed quickly and does not bark?
Cat
2. According to the key, list the features that can
identify a mouse.
Breeds quickly, has small ears and does not live in
water.
3. Why might criteria such as ‘has big ears’ and
‘doesn’t breed quickly’ cause confusion when
classifying some animals using this key?
These things are hard to measure without criteria.
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Exercise 2: A lolly key
Task Outline:
Your group has been given a collection of assorted lollies. No two lollies are the same. Your task is
to determine the characteristics that make each lolly different and to design a dichotomous key that
could be used by a person unfamilar with their names to identify each lolly.
Remember that in a dichotomous key, there can only be two choices at each level of the key. Every
lolly still to be classified must fit into one of the two groups. Be very specific in your criteria for
grouping and avoid subjective criteria (eg big or small).
After you have planned your key, make a neat copy in the space provided below.
LOLLIES
Mi nty, Jaffa, Fantail ,
Coolmint, Snake, Sour
sq ui rm, Jelly baby
Wr apped
Unwrapped
Yellow and
blue wrapper
No yel low and
blue wrapper
FANTAIL
MINTY
Round
Not round
White
Not whi te
Sug ar coated
COOL M INT
JAFFA
SOUR
SQUIR M
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Not sug ar
coated
Shaped li ke
an ani mal
Not shaped
li ke an animal
SNAKE
JELLY BABY
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Exercise 3: A dichotomous key of common objects in a pencil case
1.
Imagine you did not know what each type of stationary looked like, but you had the key to
help. For each type of stationary, use the key to identify THREE features of the stationary:
(a)
protractor
It is made of plastic that is clear and in the shape of a semi-circle.
(b)
stapler
It is made of plastic and has larger metal parts that move.
(c)
black biro
It is made of plastic that is not clear. It has a lid that is black.
2.
Is the key above dichotomous? How can you tell?
No as there are often more than TWO choices for some criteria.
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Exercise 4: A branching key of invertebrates in the park
1.
Is the key above dichotomous? No
2.
What do all invertebrates have in common? (hint: this is not answered in the key)
They do not have a backbone.
3.
Identify the invertebrate with:
(a) three pairs of legs, no wings and a white body
Springtail
(b)
no legs, a long, soft and rounded body which is not divided into rings
Roundworm
(c)
three pairs of legs and one pair of clear wings
Fly
4.
Describe the features of a tick as clearly and concisely as possible, using only information in
the key.
A tick is an invertebrate that has four pairs of legs and its head is smaller than its body.
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KEY TYPE 2: SENTENCE KEYS
This type of key is written out as sentences, often in a table. Again, to determine the name of an
object, you observe the object carefully and start at the top of the key. Read the sentence, observe
the object and follow the correct directions as you move through the key, until you reach the name
of the object.
For example, to classify dinosaur C using the key, observe its features as you follow through the
key. Starting at Number 1, ask yourself if it has wings. Since it does not, go to Number 2. Ask
yourself if it has bony plates across its back. Since it does, C must be a Stegosaurus.
You can also read the key backwards to determine the features of an object/organism if you know
its name. For example, from the key we know that Apatosaurus walks on four legs, has no horns
and no bony plates on its back and it has no wings.
Exercise 5: Creating a flowchart key from a sentence key
Convert the key above into a flow-chart type key.
DINOSAURS
Pte rso saur , Steg osa urus,
Triceratops,
Tyr annosauru s,
Apastosaur us
No Wings
Win gs
PTEROSAUR
No bony
plates on
back
Bony pla tes
on back
STEG OSAURUS
Horns
TRICERATOPS
No horns
Wa lks on 2
legs
TYRANNOSAURUS
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Wa lks on 4
legs
APATOSAURUS
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Exercise 6: Using a sentence key
The dichotomous key below classifies some common objects but it assigns them a silly scientific
name instead of their common name.
Use the key to determine the silly scientific name for these common objects.
Object as we know it
1. White marble
Silly Scientific name
Whatnot
2
Wadget
3
Unsharpened
pencil
White chalk
Object as we know it Silly Scientific name
6.
Coloured
Fancy whatnot
marble
7.
Small paperclip Itsy bitsy
Screecher
8.
Eraser
Oopsey
4
Wooden splint
Gadget
9.
Dice
Cubey
5
Sharpened pencil
Widget
10.
Large paperclip
Super duper
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KEY TYPE 3: CIRCULAR KEYS
These keys are in the shape of circles, with the broadest groupings in the centre, which is where you
should start. You then work your way to the outside where you will find the name of the object you
are trying to classify. To identify features of an object or organism given its name, work from the
outside in.
Exercise 7: Using a circular key to classify insects
Study the key below and answer the questions that follow.
1.
Use the key to identify the following insects:
(A)
(B)
(C)
(D)
(E)
2.
Segmented worm
Centipede
Dragonfly
Fly
Earwig
List the differences between a millipede and a centipede.
A millipede has two pairs of legs per segment whilst the centipede has one pair of legs per
segment.
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Exercise 8: Using a circular key to classify birds
1.
Use the key to identify the following insects:
(A)
(B)
(C)
(D)
2.
Wren
Bronze wing
Whistler
Crescent honeyeater
Contrast the appearance of a finch and a thornbill.
The finch has a stout bill and the thornbill has a slender bill
3.
If you saw a bird that looked like a whistler but had a longer, more slender bill, what could it
be?
Tree creeper OR Fantail
4.
Describe in a clear sentence the features of a red wattle bird.
Red wattle bird has a body larger than a sparrow. It is not coloured black or brown nor is it
brightly coloured.
5.
Which bird is most like a crescent honey eater?
New Holland honeyeater
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