8/13/2011
Essential Question
Chapter 18:
Classification
What is the goal of biologists
who classify living things?
Mrs. Bertolotti
Assigning Scientific Names
Explain the characteristics of
binomial nomenclature.
► In
the eighteenth century, European scientists
agreed to assign Latin or Greek names to each
species. Early scientific names often used long
phrases to describe species in great detail.
► For example, the English translation of the
scientific name of a tree might be “Oak with
deeply divided leaves that have no hairs on their
undersides and no teeth around their edges.”
► It was also difficult to standardize names because
different scientists focused on different
characteristics
Early classification systems
names of organisms vary depending on
the location of the organism
 Ex. A buzzard in North America refers to a
vulture whereas in United Kingdom it refers to a
hawk.
 A cougar is called a panther, puma, mountain
lion
► Scientists decided to use Latin or Greek names but
the descriptions were too long.
► Carl Linnaeus then developed a system that uses a
scientific name to refer to one and only one
species
Carl Linnaeus
► Common
► Scientist
who developed a
classification system for
living things.
► Wrote book Systema
Naturae in 1735 to
reveal his classification
system.
1
8/13/2011
Finding order in diversity
► To
study the diversity of life, biologists use
a classification system to name organisms
and group them in a logical manner
 Taxonomy is a discipline of classifying
organisms and assigning each organism a
universally accepted name
► Carlos
Linnaeus developed a two word
naming system called binomial
nomenclature which is a classification
system in which each species is assigned a
two--part scientific name
two
scientific name is always written in italics.
first word is capitalized and the second word
is lowercase,
► The
► The
 Example: The scientific name of a grizzly bear is Ursus
arctos
► The
first part of the scientific name is the genus to
which the organism belongs
 Genus is a group of closely related species, and the
first part of the scientific name in binomial
nomenclature
► The
second part of the scientific name is unique to
each species within the genus.
 Often it is the latinized description of some important
trait of the organism or an indication of where it lives
Example
Scientific Naming
► Homo
► Binomial
nomenclature- unique
nomenclature2-word name assigned by
scientists.
 1st word is the genus, 2nd is the
species.
 Genus
Genus-- group of organisms that
share similar characteristics.
 Species
Species-- group of organisms that
can successfully breed within
their group, but not others.
sapiens:
 Homo = genus
 sapiens = species
 Common name = humans
► Quercus
rubra–
 Quercus = genus
 rubra = species
 Common name = red oak
Mantis religiosa
Explain the characteristics of
binomial nomenclature.
► Scientific
names are in Latin b/c scholars in the
Middle Ages communicated using it!
Explain how living things are
grouped.
2
8/13/2011
Classification
Linnaeus’ system of classification
► Is
hierarchical-- or consists of levels
hierarchical
► Includes 7 levels from smallest to largest species, genus, family, order, class, phylum,
and kingdom
► Each of these 7 levels is called a taxon or a
group or level of organization into which
organisms are classified
Classification
► Scientists
have determined seven levels of
classification:







Kingdom = King
Kingss
Phylum = Pass
Class = Class
Classes
es
Order = to Order
Family = Famili
Families
es
Genus = and their Good
Species = Sons around
Classification
 Kingdom
 Phylum
 Class
 Order
 Family
 Genus
 species
Organizing systems
► Making
sense out of the differences
Eastern gray squirrel
Sciurus carolinensis
3
8/13/2011
Classification of Modern
Humans
► Kingdom
= Animalia
= Chordata
► Class = Mammalia
► Order = Primates
► Family = Hominidae
► Genus = Homo
► Species = sapiens
► Phylum
VOCABULARY
Species is a group of individuals capable of
interbreeding and producing fertile offspring
► Genus is a group of similar species
► Genera share many characteristics and are grouped
into a larger category called the family
► An order is a broad taxonomic category composed of
similar families
► A class is composed of similar orders
► Several different classes make up a phylum which
share important characteristics such as body plan and
internal functions
► The kingdom is the largest and most inclusive of
Linnaeus’s taxonomic categories
►
Explain how living things are
grouped.
Modern Evolutionary Classification
►
Darwin’s ideas about descent with modification have given
rise to the study of phylogeny or evolutionary
relationships among organisms
 The goal of phylogeny classification or evolutionary
classification, is to group species into larger categories
that reflect lines of evolutionary descent, rather than
overall similarities and differences
►
Biologists now group organisms into categories that
represent lines of evolutionary descent or phylogeny, not
just physical similarities
►
Species within a genus are more closely related to each
other than a species in another genus because all
members of a genus share a recent common ancestor
How does evolutionary
classification work?
4
8/13/2011
► The
higher the level of the taxon
taxon,, the
farther back in time is the common ancestor
of all the organisms in the taxon
► Organisms that appear very similar may not
share a recent common ancestor
► To refine the process of evolutionary
classification, many biologists now prefer a
method called cladistic analysis which
identifies and considers only those
characteristics of organisms that arise as
lineages evolve over time
Building Cladograms
 A speciation event, in which an ancestral
lineage branches into two new lineages, is the
basis for each branch point, or node. Each node
represents the last point at which the new
lineages shared a common ancestor.
►
Characteristics that appear in recent parts
of a lineage but not in its older members
are called derived characters
 A derived character is a trait that arose in the
most recent common ancestor of a particular
lineage and was passed along to its
descendants.
►
A cladogram can be constructed to show
derived characters
 A cladogram links groups of organisms by
showing how evolutionary lines, or lineages,
branched from common ancestors
Building Cladograms
 A cladogram’s branching patterns indicate
degrees of relatedness among organisms.
 Because lineages 3 and 4 share a common
ancestor more recently with each other than
they do with lineage 2, you know that lineages 3
and 4 are more closely related to each other
than they are with lineage 2.
 The bottom, or “root,” of the tree represents
the common ancestor shared by all organisms
on the cladogram
cladogram..
Building Cladograms
 Likewise,
Likewise, lineages 2, 3, and 4 are more closely
related, in terms on ancestry, with each other
than any of them is to lineage 1.
Building Cladograms
 This cladogram represents current hypotheses
about evolutionary relationships among
vertebrates.
 Note that in terms of ancestry, amphibians are
more closely related to mammals than they are
to rayray-finned fish!
5
8/13/2011
Cladogram
Reading Cladograms
 This cladogram shows a simplified phylogeny of
the cat family.
► Cladograms
are useful in helping scientists
understand how one lineage branched from
another in the course of evolution
How does evolutionary
classification work?
► The
How are DNA sequences used
in classification?
genes of many organisms show important
similarities at the molecular level. Similarities in
DNA can be used to help determine classification
and evolutionary relationships
► A molecular clock is a model that uses DNA
comparisons to estimate the length of time that
two species have been evolving independently
 A comparison of DNA sequences in 2 species
can reveal of similar the genes are and thus
how long ago the 2 species shared a common
ancestor
 This process is not simple because there is
more than 1 molecular clock in a genome
6
8/13/2011
How are DNA sequences used
in classification?
What are the 6 kingdoms and 3
domains of life?
6 Kingdoms
Kingdoms and Domains
► There
are 6 kingdoms:
 Eubacteria,
Eubacteria, Archaebacteria
Archaebacteria,, Protista
Protista,, Fungi, Plantae
Plantae,, and
Animalia
► The
domain is the most inclusive category and
refers to a category that is larger than a kingdom
► There are 3 domains:
 1. Eukarya (composed of protists
protists,, fungi, plants, and
animals)
 2. Bacteria (corresponds with kingdom Eubacteria
Eubacteria))
 3. Archaea (corresponds with kingdom Archaebaceteria
Archaebaceteria))
Kingdom Protista
composed of eukaryotic organisms that
cannot be classified as animals, plants, or
fungi
► Its members display the greatest variety
► Some are autotrophs and others
heterotrophs
►
► There
are six kingdoms all living
things are classified into:






Animals
Plants
Eukaryotes
Fungi
Protists
Eubacteria
Prokaryotes
Archeabacteria
Diseases caused by protists
Symptoms:
First stage: fever, headaches, itching,
and joint pains
Second stage: confusion, mental
deterioration, eventual death without
treatment
► African
Sleeping
Sickness
caused by Trypanosoma
► Malaria
Plasmodium
Symptoms:
fever, vomiting, anemia, convulsions,
headaches, sweating
► Amebic
Dysentery
Caused by Ameba histolytica
Symptoms:
Stomach pains and frequent passage
of feces, presence of mucus or blood
in the feces
7
8/13/2011
Kingdom Fungi
►
members are heterotrophs
Fungi
► All
fungi are
eukaryotic
Unicellular (yeast)
► They
may be
unicellular or
multicellular
Multicellular
► All
fungi have a
cell wall
Fungi
Fungi
Penicillin
► Fungi
can be very
helpful and delicious
► Many antibacterial drugs
are derived from fungi
► Fungi accounts for the
blue vein in blue
cheese!
Kingdom Plantae
members are multicellular
► Photosynthetic
► are nonnon-motile: or they cannot move from
place to place
►
► Fungi
also causes a number of plant and
animal diseases:
Athlete's Foot
Ringworm
► 4 important plant groups are the:
Non-vascular
Mosses
(Bryophytes)
Conifers
(Gymnosperms)
Ferns (Pteridophytes)
Vascular
Flowering Plants
(Angiosperms)
8
8/13/2011
Nonvascular Plants - Mosses
► Mosses
 the simplest of all land dwelling plants
Nonvascular (no “veins”)-lack an internal means
for water transportation
 do not produce seeds or flowers
- fertilization depends on water medium to get the sperm to the egg.
 lack a woody tissue necessary for support around
their “stems” and so are usually relatively short
Vascular Plants
Plants-Angiosperms and Gymnosperms
Gymnosperms
 Conifers (pine cones)
 Oldest vascular plants
•Internal transportation System
• Xylem – water carrying tubes
• Phloem – sugar carrying tissues
• enables plants to evolve into larger
specimens.
•Produce Seeds – protects and nourishes an
Embryo of the new plant
Angiosperms
- flowering plants
Kingdom Animalia
members are multicellular and
heterotrophic
► Do not have a cell wall in their cells
►
9
8/13/2011
Criteria for Animal Classification
► Kingdom
 Phylum
► Skeletal
Characteristics
 Invertebrates
have a hard external skeleton made of
chitin known as an exoskeleton
 Vertebrates
have a hard internal skeleton made of
bone or cartilage
► Porifera
Porifera::
sponges
 Reproduces both sexually and asexually
► Mollusks
 Octopi, squid
 Class
► Order
►
Family
►
Genus
►
Species
Major phylums of animals
are…
► Cnidarians
Cnidarians::
 Jellyfish,
Jellyfish, corals, and other stingers. . . Their stinger is
called a nematocyst
► Mollusks
 Clams, oysters
10
8/13/2011
► Platyhelminthes
► Mollusks
 Snails, slugs
(flat worms)
 Tapeworms & Liver Fluke & Planaria
 Hermaphrodites
Hermaphrodites--fertilize their own sex cells
internally then zygotes are released into
water to hatch
Human liver fluke
► Annelids
(segmented worms)
 Worms & leeches
► Arthropods
 Shell fish, arachnids & BUGS!
► Echinoderms
 Starfish, sea urchins, sea cucumbers
► Chordates
 all other animals that have a backbone of
some form
11
8/13/2011
Domain Bacteria
► The
members are
 1. unicellular
 2. prokaryotic
 3. cell walls contain peptidoglycan
► The
domain corresponds to the kingdom
Eubacteria
Domain Archae
Domain Eukarya
Consists of all organisms that have a
nucleus and are eukaryotic
► Organized into 4 remaining kingdoms of
the 6 kingdom system: Protista
Protista,, Fungi,
Plantae,, and Animalia
Plantae
►
► Members
are:
 1. unicellular
 2. prokaryotic
 3. live in EXTREME environments such as
volcanic hot springs
 4. most will die in the presence of oxygen
► The
domain Archaea corresponds to the
kingdom Archaebacteria
Essential Question
What are the 6 kingdoms and 3
domains of life?
What is the goal of biologists
who classify living things?
12