The document discusses problems with common names for organisms and how scientific names are used to precisely identify species. It introduces binomial nomenclature, which assigns every species a two-part Latin or Latinized name. This naming system was developed by Carolus Linnaeus and allows unambiguous identification of organisms around the world. The document also discusses the hierarchical taxonomic classification system and how dichotomous keys can be used to identify unknown organisms.

1. Classification (3.4.2)

2. Problems with Naming
Organisms
 Your are probably familiar with the
common names of organisms like dogs,
cats, worms, jellyfish, oak trees and
rockfish.
 However, sometimes there can be more
than one common name for certain
organisms depending on where you live.
 Also there can be more than one species
with the same common name.
 How can we tell the difference between
species or know what organism we are
talking about?

3. Problem of the Puma
 The mountain lion is the largest cat found
in North America.
 However, the mountain lion has more
than one name depending on who you are
talking to.
 It is also called the puma, catamount,
nittany lion, cougar, or painter.
 So, if you don’t know all of the common
names, how can you know exactly that
someone is talking about a mountain
lion?

4. Felis concolor
 In order to prevent confusion,
we use scientific names when
talking about specific animals.
 These names are made up of
two Latin or Latinized
words.
 Now, if you say you are talking
about Felis concolor, any
person in the world knows
exactly what animal you are
talking about!

5. Vocabulary
Taxonomy Binomial nomenclature
Scientific name Taxon
Kingdom Phylum
Class Order
Family Genus
Species Dichotomous key

6. Taxonomy
 Taxonomy is the science of naming
and classifying organisms.
 Aristotle began grouping
organisms based on their
similarities over 2000 years ago.
 In 1735, Swedish biologist named
Carl Linnaeus came up with a two-
word Latinized system of naming
organisms based on their
similarities.
 Linnaeus’ system is called binomial
nomenclature.

7. Binomial Nomenclature
 Felis, Musca, domestica, americanus
 What’s
up with these funny sounding
names?
 They are either Latin or Latinized
words that describe the organism
they identify.

8. What’s Up with Latin!?!
 We use Latin because no one speaks
Latin anymore.
 The
words never change their
meaning and there is no confusion.
 These terms are also descriptive.
 Whatdo you think the names
domestica and americanus tell us
about those organisms?

9. Binomial Nomenclature
 Let’s look at a scientific name —Felis
domesticus.
 Felis is the Genus name and domesticus
is the species name.
 The Genus refers to a group of closely
related species. In this instance, Felis
refers to cats.
 The species name only refers to one
organism. It is used to describe the
organism.
 The name domesticus refers to our
domesticated house cat.

10. Rules for Binomial
Nomenclature
 Names consist of two words—Genus and
species.
 Both words are italicized or underlined.
 Genus is always capitalized.
 species is always lower-case
 Both names are in Latin or Latinized.
 Two different organisms cannot have the
same name.
 The species name has to be different
within the same Genus.

11. Scientific Names
Homo Panthera
sapiens leo
People Lion
Musca Acer
domestica rubrum
House Red
Fly Maple

12. Classification
Most inclusive  Kingdom
Phylum
Class
Order
Family
Genus
Most exclusive  species

13. Classification
 You need to know each level—taxon—of
classification.
 So, come up with a phrase that helps you
remember the levels in order.
 I like to use King Philip Came Over For George’s
sword (Kingdom-Phylum-Class-Order-Family-Genus-
species)
 Remember, each level is called a taxon.
 Each taxon contains the organisms in the taxon
below.
 So, if two organisms are in the same family, they
are also in the same order, class, phylum and
kingdom.

14. Examples and Meanings
 One great thing about classifying organisms
is that the taxon names have meanings that
describe the organisms in those taxa.
 The following six slides show the
classification of great white sharks, striped
bass, the common house fly, the blue crab,
chimpanzees and humans.
 All are in the Kingdom Animalia (animals).
 Hopefully you will notice the similarities and
differences contained in the meanings of
their scientific names. Enjoy!

15. Great White Shark
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
(fish with cartilage instead of bones)
Order: Lamniformes
Family: Lamnidae
Genus: Carcharodon (“ragged tooth”)
Species: carcharias (“shark”)

16. Striped Bass (Rockfish)
Kingdom: Animalia
Phylum: Chordata
Class: Osteichthyes (fish with bones)
Order: Perciformes (perch-like fish)
Family: Moronidae (temperate basses)
Genus: Morone
Species: saxatilis (“dwelling among rocks”)

17. Common Housefly
Kingdom: Animalia
Phylum: Arthropoda (“jointed foot”)
Subphylum: Hexapoda (“six-legged”)
Class: Insecta
Order: Diptera (flies with one pair of wings)
Family: Muscidae (stocky flies with large eyes)
Genus: Musca
Species: domestica (“domestic”)

18. Blue Crab
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea (lobsters, crabs, shrimp)
Class: Malacostraca
Order: Decapoda (“ten legs”)
Family: Portunidae (swimming crabs)
Genus: Callinectes (“beautiful swimmer”)
Species: sapidus (“delicious”)

19. Chimpanzee
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae (great apes and humans)
Genus: Pan
Species: troglodytes (“cave man”)
Seems that the scientific name for chimpanzees
comes from people originally thinking that
chimps looked like “cave men”!!!

20. Humans
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae (great apes and humans)
Genus: Homo (“man”)
Species: sapiens (“knowing” or “thinking”)

21. Some questions…
 Which of the previous organisms is most
closely related to humans?
Chimpanzees (they are both in the same family)
 What is the major difference between the
great white shark and the striped bass?
Sharks have cartilage and bass have bones
 Why are the housefly and blue crab both
put into the same Phylum—Arthropoda?
They both have jointed appendages (legs)

22. Use the information on the next
three slides to answer a few
questions HERE.

23. Black Bear (Ursus americanus)
 Kingdom—Animalia (multicellular eukaryotes, no
cell walls and heterotrophic)
 Phylum—Chordata (endoskeleton and a hollow
nerve cord)
 Class—Mammalia (mammary glands,
endothermic metabolism, hair and specialized
teeth)
 Order—Carnivora (three pairs of incisors on
upper and lower jaws with large canines)
 Family—Ursidae (stocky and powerful, densely
furred bodies with small ears, closely set eyes
and a prominent muzzle)

24. Red Maple (Acer rubrum)
 Kingdom—Plantae (multicellular
eukaryotes, autotrophic with cell walls)
 Division—Magnoliophyta (vascular
tissues, true roots, stems, leaves and
flowers; enclosed seeds)
 Class—Magnoliopsida (two seed parts)
 Order—Sapindales
 Family—Sapindaceae (deciduous, toothed
leaves and winged fruit)

25. Cyanobacteria (Anabaena spp.)
 Kingdom—Bacteria (single-celled
prokaryotes that lack membrane-bound
organelles)
 Division—Cyanophycota (autotrophic with
some being nitrogen fixers)
 Class—Cyanophyceae
 Order—Nostocales (filamentous, motile
and reproduce through binary fission)
 Family--Nostocaceae

26. Use the table below to answer a
few questions HERE.
Common Human Lion House Cat
name
Kingdom Animalia Animalia Animalia
Phylum Chordata Chordata Chordata
Class Mammalia Mammalia Mammalia
Order Primate Carnivora Carnivora
Family Homonidae Felidae Felidae
Genus Homo Panthera Felis
species sapiens leo domesticus

27. DICHOTOMOUS
KEYS
A dichotomous key is a tool used to
identify unknown things.

28. A B C D
Use the following dichotomous key
to identify the tools above.

29. A B C D
1a. It requires electricity… Circular saw
1b. It does not require Go to 2
electricity…
2a. It has teeth… Hack saw
2b. It does not have teeth… Go to 3
3a. It has a blunt metal head… Hammer
3b. It has a flat, triangular head… Trowel

30. A B C D
Hammer Hack Trowel Circular
saw saw
How did you figure out the
names of these tools?

31. How to use the dichotomous key
 Look at what you are trying to
identify (duh!)
 Read the description for 1a.
 If the description doesn’t match,
then go to 1b.
 Follow the directions until you
find the correct description of
your mysterious object!

32. Bringing It Together
 Taxonomy is the science of naming and
classifying organisms.
 A scientific name contains two Latin or
Latinized terms that describe an
organism. This is also called binomial
nomenclature.
 Remember—scientific names are usually
descriptive. Domesticus means domestic
and Americanus means it is found in
America!

33. Bringing It Together
 Remember your taxa in order—
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species
 All organisms in one taxon are also in the same
taxa above. For example, organisms in the same
Order would also be in the same Kingdom,
Phylum and Class.

34. Bringing It Together
 Organisms are grouped together based
on similarities. For example, fish and
birds are in the same kingdom and
phylum because they have a backbone
and are animals.
 A dichotomous key is used to identify
things based on their appearances.