Unit 1: Diversity
Activity 1: Classification of Living Things
Imagine you had to empty out all the contents of your pencil case and try to organize
them into specific categories and then identify them. Depending on the items you
have, it may take you a few moments, but in time, you will probably develop groups
of items that have similar features. Perhaps you separated pens from pencils and
erasers from white out. Or maybe you grouped all the writing tools (pens, pencils,
etc.) together and separated them from non-writing tools (erasers, paperclips, glue
stick, etc.) Now imagine trying to classify all the organisms on Earth into specific
groups.
This task began long before you were born. In fact, it
began 2300 years ago with Greek philosopher Aristotle
identifying 1 000 different types of organisms. At that time,
Aristotle grouped organisms according to their habitat.
There were land dwellers, water dwellers and air dwellers.
Aristotle also arranged species by their complexity and
arranged them in order from least complex to highly
complex. As we will learn, the hierarchy arrangement that
Aristotle proposed is similar to the system we use today.
Swedish botanist
__________________(1707 1778) created our current
classification system. Over 300
years ago, Linnaeus arranged organisms based upon
their __________ and ______________ features. Thus,
began the process of taxonomy. ______________ is the
science of classifying organisms into similar groups so
that when a new organism is found it can be identified. It
also illustrates the relationship between similar
organisms.
Aristotle as a young
philosopher.
Linnaeus
Similar to Aristotle's hierarchy, Linnaeus also developed
levels of organization: kingdom, phylum, class, order, family, genus, and species.
Individual groups are called a _____________(plural taxa). Kingdom represents the
highest level and the most number of organisms, whereas, species contain only one
type of organism in its taxa. The chart below shows the order from highest to lowest
and a mnemonic that you can use to help you remember the hierarchy.
King
Peter
Came
Over
For
Good
Spaghetti
Linnaeus also developed a tool, which is currently used today, to name specific
organisms. ________________________assigns each organism a two word name in
either Latin or Greek. This naming system only represents the __________ and
__________ classification of the organism and omits the other five levels. For
example, the scientific name for humans is Homo sapiens. Hopefully you notice that
the names are written in __________. The genus name is always written in italics
and is capitalized, and the species is also written in italics, but it is not capitalized.
Here is a sample of common names for familiar organisms. Let's see if you are able
to match up the correct scientific name.
Practice Question
1. Match the organisms in the left hand column with their correct scientific names
in the right hand column.
Common Names
Scientific Names
Taraxacum officinale
Acer palmatum
Japanese Maple
Rangifer tarandus
Reindeer
Dandelion
At first, there were two main kingdoms: _________ and ____________. As time went
on, it became apparent that more kingdoms were needed to correctly identify and
name organisms. Currently there are five kingdoms: Animalia, Plantae, Fungi,
Protista, and Bacteria. In addition, a new taxa ___________ was recently introduced
to distinguish between the different types of bacteria, which we will explore in greater
detail at a later time. The three domains are__________, __________, and
_____________.
Here is the complete classification of humans:
Domain
Eukarya
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Primates
Family
Hominidae
Genus
Homo
Species
sapiens
Remember the opening problem of identifying and
classifying the contents of your pencil case? You
probably completed it without the use of a
dichotomous key. A _____________________is a
classification manual that provides the user with a
series of options to choose from and then a link to
follow based on that choice.
For example, if we go back and explore the contents of your pencil case: pen, pencil,
eraser, paper clip, scissors, and glue stick, we can create a dichotomous key. Simply
follow the steps until you have been able to identify each item.
1.a.circular shape……….go to 2.
b.irregular shape ……..go to 3.
2.a.thin body……………..go to 4.
b.thick body ……………glue stick.
3.a.Metallic lustre…………… go to 5.
b.Non-metallic lustre……... eraser.
4.a.wooden body…………..pencil
b.plastic body…………… pen
5.a.malleable…………….. paper clip
b.non-malleable ……..…scissors
A Phylogenetic Tree
A ________________tree can be used to show
the evolutionary history of a particular organism.
It resembles a tree with a trunk and many
branches that diverge. A phylogenetic tree will
show a common ancestor and the many
different organisms that have branched away.
This phylogenetic tree shows the evolution of all
living things. Each branch contains organisms
that have diverged from the common ancestor.
As you can see, each group diverges at different
times when their characteristics changed and no
longer resemble their ancestor.
Assignment
Complete the following assignment and submit your work to your teacher.
Using a Dichotomous Key
1. Use the illustrations of flowering plants and the dichotomous key to identify
each flower.
Image 1
Image 2
Image 3
Image 4
Image 5
Image 6
2. 1.a.Flower has more than six petals……..go to 2.
b.Flower has less than six petals………go to 3.
3. 2.a.Petals are arranged tightly…………….Taraxacum officinale
b.Petals are spread out…………………..go to 4.
4. 3.a.White petals……………………………...Geranium richardsonii
b.Petals are purple………………………...Geranium viscosissimum
5. 4.a.Petals are pointed……………………….go to 5.
b.Petals are rounded………………………Sphaeralcea coccinea
6. 5.a.Petals are thin and yellow……………… Balsamorhiza sagittata
b.Petals are short and purple…………….Symphyotrichum novi-belgii
7. Determine the common name of each of the flowers and arrange your solutions
into an organized table as shown below.
Image
Scientific Name
Common Name
1
2
3
4
5
6
8. Create your own dichotomous key for the following images. Remember to
choose distinguishing features to separate each organism.
Atractosteus spathula
Alosa pseudoharengus
Ictalurus punctatus
Acipenser oxyrhynchus
Pomoxis nigromaculatus
Esox niger