Transcript Document

Chapter 4 Classification and
Phylogeny
Carolus Linnaeus
• Swedish botanist
• Produced a
classification scheme
for plants and
animals
• Published “Systema
Naturae”
1707-1778
Linnean system of
classification
Linnean system of
classification
1. All animals have a unique name
Linnean system of
classification
1. All animals have a unique name
This name is a binomial
Genus name
Species epithet
Linnean system of
classification
1. All animals have a unique name
This name is a binomial
Genus name
Species epithet
2. Organisms are arranged into groups
based on relatedness
Linnean system of
classification
1. All animals have a unique name
This name is a binomial
Genus name
Species epithet
2. Organisms are arranged into groups
based on relatedness
Hierarchical system of classification
Hierarchical system
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
What is in a name?
• Genus name: Homo
• Species name:
Homo sapiens
Note:
Complete species name
Cap of genus name but not
specific epithet
Italicization (underline)
Phylogenetics
• The scientific study of the relationships
between the many different kinds of life
on Earth
Phylogenetics
• The scientific study of the relationships between the
many different kinds of life on Earth
– Includes methods of collecting and analyzing
data and interpreting the results
Phylogenetics
• The scientific study of the relationships between the
many different kinds of life on Earth
– Includes methods of collecting and analyzing data
and interpreting the results
• The Emphasis is on common descent
Definitions
1. Ancestral character state: character
shared by all members within a group.
Definitions
1.
Ancestral character state: character shared by all
members within a group.
2. Derived characters: character unique to
a group or groups.
Definitions
1.
2.
Ancestral character state: character shared by all
members within a group.
Derived characters: character unique to a group or
groups.
3. Outgroup: organism we will compare
the ingroup to.
Definitions
1.
2.
3.
Ancestral character state: character shared by all
members within a group.
Derived characters: character unique to a group or
groups.
Outgroup: organism we will compare the ingroup to.
4. Clade: subset of closely related
organisms within a group.
Definitions
1.
2.
3.
4.
Ancestral character state: character shared by all
members within a group.
Derived characters: character unique to a group or
groups.
Outgroup: organism we will compare the ingroup to.
Clade: subset of closely related organisms within a
group.
5. Synapomorphy: a derived character shared
by all members within a clade.
1. Ancestral character
state
2. Derived characters
3. Outgroup
4. Clade
5. Synapomorphy
What kind of characters are
used
• Comparative morphology: structural
What kind of characters are
used
• Comparative morphology: structural
• Comparative cytology: chromosomes
What kind of characters are
used
• Comparative morphology: structural
• Comparative cytology: chromosomes
• Comparative biochemistry: genetic
What kind of characters are
used
• Comparative morphology: structural
• Comparative cytology: chromosomes
• Comparative biochemistry: genetic
Total Evidence
Any character can fall into three
categories
Any character can fall into three
categories
• Monophyletic: shared by all members of
a group.
Any character can fall into three
categories
• Monophyletic: shared by all members of
a group.
• Paraphyletic: not shared by all members
within a group.
Any character can fall into three
categories
• Monophyletic: shared by all members of
a group.
• Paraphyletic: not shared by all members
within a group.
• Polyphyletic: found in more than one
group.
Analyses of phylogeny
Species?
• How do you define it?
Species?
• How do you define it?
• Start with common descent
Species?
• How do you define it?
• Start with common descent
• After that, all modern concepts of species
differ.
Species?
–
–
–
–
–
–
–
–
Ecological species concept
Recognition species concept
Diagnostic species concept
Evolutionary species concept
Cohesion species concept
Phenetic species concept
Phylogenetic species concept
Biological species concept
Species?
–
–
–
–
–
–
–
–
Ecological species concept
Recognition species concept
Diagnostic species concept
Evolutionary species concept
Cohesion species concept
Phenetic species concept
Phylogenetic species concept
Biological species concept
Biological species concept
• “Species are groups of interbreeding
natural populations that are reproductively
isolated from other such groups” (Ernst
Mayr 1970)
Kingdom concepts
• Five kingdom concept
• Three Domain concept
Five Kingdom
Five Kingdom
• Note that
Protists and
Monera are
paraphyletic
Three Domains
• Note that the
“Monera has
been split into
two groups.
• Everything
else belongs
into a single
group.
Chordata
Arthropoda
Annelida
Mollusca
Protostomes
Hemichordata
Echinodermata
Deuterostomes
Coelomates
†
Triploblasts
* Diploblasts
Acoelomates
Bilateria†
Mesozoa
Pseudocoelomates
Radiata*
Eumetazoa
Metazoa
Protozoa
Monera (Bacteria)
Cnidaria
Ctenophora
Parazoa
The Big Picture
The Big Picture
• Linnaeus constructed the nomenclatural
system we use today
The Big Picture
• Linnaeus constructed the nomenclatural system we use
today
• Systematics allow biologists to determine
the relationships of organisms
The Big Picture
• Linnaeus constructed the nomenclatural
system we use today
• Systematics allow biologists to determine the
relationships of organisms
• The definition of a “species” still
confounds biologists. We are now
realizing that a single definition may not
be enough.
The Big Picture
• Linnaeus constructed the nomenclatural
system we use today
• Systematics allow biologists to determine the
relationships of organisms
• The definition of a “species” still confounds
biologists. We are now realizing that a single
definition may not be enough.
• The “Five Kingdom” concept is used for
convenience not accuracy.