Download Essential Knowledge 1.B.1

BIG IDEA I
The process of evolution drives
the diversity and unity of life.
Enduring Understanding 1.B
Organisms are linked by lines of descent from common ancestry.
Essential Knowledge 1.B.1
Organisms share many conserved core processes and features
that evolved and are widely distributed among organisms today.
PowerPoint® Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Essential Knowledge 1.B.1: Organisms share many conserved core processes
and features that evolved and are widely distributed among organisms today.
• Learning Objectives:
–
(1.14) The student is able to pose scientific questions that
correctly identify essential properties of shared, core life
processes that provide insights into the history of life on Earth.
–
(1.15) The student is able to describe specific examples of
conserved core biological processes and features shared by all
domains or within one domain of life, and how these shared,
conserved core processes and features support the concept of
common ancestry for all organisms.
–
(1.16) The student is able to justify the scientific claim that
organisms share many conserved core processes and features
that evolved and are widely distributed among organisms
today.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
New Information Continues to Revise our Understanding of the
Tree of Life
• Recently, we have gained insight into the very deepest
branches of the tree of life through molecular
systematics.
• Early taxonomists classified all species as either plants
or animals.
• Later, five kingdoms were recognized: Monera
(prokaryotes), Protista, Plantae, Fungi, and Animalia.
• More recently, the three-domain system has been
adopted: Bacteria, Archaea, and Eukarya.
• The three-domain system is supported by data from
many sequenced genomes.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 26-21
EUKARYA
Dinoflagellates
Forams
Ciliates Diatoms
Red algae
Land plants
Green algae
Cellular slime molds
Amoebas
Euglena
Trypanosomes
Leishmania
Animals
Fungi
Sulfolobus
Green nonsulfur bacteria
Thermophiles
Halophiles
(Mitochondrion)
COMMON
ANCESTOR
OF ALL
LIFE
Methanobacterium
ARCHAEA
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Spirochetes
Chlamydia
Green
sulfur bacteria
BACTERIA
Cyanobacteria
(Plastids, including
chloroplasts)
The Three Domain System
•
Describes classification as:
–
Not all prokaryotes are closely related (not
monophyletic)
–
Prokaryotes split early in the history of living things
(not all in one lineage)
–
Archaea are more closely related to Eukarya than to
Bacteria
–
Eukarya are not directly related to Bacteria
–
There was a common ancestor for all extant
organisms (monophyletic)
–
Eukaryotes are more closely related to each other
(than prokaryotes are to each other)
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Fig. 26-UN9
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Classification of Living Things
Go to
Section:
Structural and functional evidence supports
the relatedness of all domains.
• Illustrative examples include:
1. DNA and RNA are carriers of genetic information
through transcription, translation and replication.
2. Major features of the genetic code are shared by all
modern living systems (Central Dogma).
3. Metabolic pathways are conserved across all currently
recognized domains.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Structural evidence supports the relatedness of all
eukaryotes.
• Illustrative examples include:
1. Cytoskeleton
2. Membrane-bound Organelles
3. Endomembrane Systems
4. Linear Chromosomes
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
BIG IDEA I
The process of evolution drives
the diversity and unity of life.
Enduring Understanding 1.B
Organisms are linked by lines of descent from common ancestry.
Essential Knowledge 1.B.2
Phylogenetic trees and cladograms are graphical representations
(models) of evolutionary history that can be tested.
PowerPoint® Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Essential Knowledge 1.B.2: Phylogenetic trees and cladograms are graphical
representations (models) of evolutionary history that can be tested.
• Learning Objectives:
–
(1.17) The student is able to pose scientific questions about a
group of organisms whose relatedness is described by a
phylogenetic tree or cladogram in order to (1) identify shared
characteristics, (2) make inferences about the evolutionary
history of the group, and (3) identify character data that could
extend or improve the phylogenetic tree.
–
(1.18) The student is able to evaluate evidence provided by a
data set in conjunction with a phylogenetic tree or a simple
cladogram to determine evolutionary history and speciation.
–
(1.19) The student is able to create a phylogenetic tree or
simple cladogram that correctly represents evolutionary history
and speciation from a provided data set.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Phylogenies show evolutionary relationships.
• Phylogeny is the evolutionary history of a species or group
of related species.
• It is constructed by using evidence from systematics, a
discipline that focuses on classifying organisms and their
evolutionary relationships. Its tools include fossils,
morphology, genes, and molecular evidence.
• Taxonomy is an ordered division of organisms into
categories based on a set of characteristics used to assess
similarities and differences.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 26-4
Order
Family Genus
Species
Taxidea
Taxidea
taxus
Lutra
Mustelidae
Panthera
Felidae
Carnivora
Panthera
pardus
Lutra lutra
Canis
Canidae
Canis
latrans
Canis
lupus
Fig. 26-2
Fig. 26-5
Branch point
(node)
Taxon A
Taxon B
Taxon C
ANCESTRAL
LINEAGE
Taxon D
Taxon E
Taxon F
Common ancestor of
taxa A–F
Polytomy
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Sister
taxa
Phylogenetic trees and cladograms can represent
traits that are either derived or lost due to evolution.
• These are graphical representations (models) of
evolutionary history that can be tested.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Derived / Lost Traits – Illustrative Examples
• Using phylogenetic trees and cladograms, we
can represent traits that are either derived
(newly evolved) or lost due to evolution.
• Illustrative examples include:
– Number of heart chambers in animals
– Absence of legs in some sea mammals
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Derived Traits – Illustrative Example
A powerful four-chambered
heart was an essential
adaptation of the endothermic
way of life characteristic of
mammals and birds.
The separation of the systemic
and pulmonary circuits, each
independently powered, allows
organisms to deliver much
more fuel and O2 to tissues –
because endotherms use about
10 times as much energy as
ectotherms.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Lost Traits – Illustrative Example
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
What We Can and Cannot Learn from Phylogenetic
Trees
• Phylogenetic trees do show patterns of descent
• Phylogenetic trees do not indicate when
species evolved or how much genetic change
occurred in a lineage
• It shouldn’t be assumed that a taxon evolved
from the taxon next to it
• Phylogeny provides important information
about similar characteristics in closely related
species
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Phylogenies are inferred from morphological and
molecular data.
• To infer phylogenies, systematists gather
information about morphologies, genes, and
biochemistry of living organisms
• Organisms with similar morphologies or DNA
sequences are likely to be more closely related
than organisms with different structures or
sequences
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 26-7
Sorting Homology from Analogy
• Bat and bird wings are homologous as forelimbs, but
analogous as functional wings.
• Homology can be distinguished from analogy by
comparing fossil evidence and the degree of
complexity.
• The more complex two similar structures are, the more
likely it is that they are homologous.
• Molecular systematics uses DNA and other molecular
data to determine evolutionary relationships. The
more alike the DNA sequences of two organisms, the
more closely related they are evolutionarily.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 26-8
1
Ancestral homologous DNA segments
are identical as species 1 and 2 begin
to diverge from their common
ancestor.
Deletion and insertion mutations shift
what had been matching sequences in
the two species.
Of the three homologous regions, two
(shaded orange) do not align because
of these mutations.
Homologous regions realign after a
computer program adds gaps in
sequence 1.
Ancestral and Derived Characters
• In comparison with its ancestor, an organism
has both shared and different characteristics:
– An ancestral character is a character that
originated in an ancestor of the taxon.
– A derived character is an evolutionary novelty
unique to a particular clade.
– Derived characters are used to construct
phylogenetic trees because they infer
evolutionary change!
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 26-11
Performing Outgroup Comparisons
TAXA
Tuna
Leopard
Lancelet
(outgroup)
Vertebral column
(backbone)
0
1
1
1
1
1
Hinged jaws
0
0
1
1
1
1
Lamprey
Tuna
Vertebral
column
Salamander
Hinged jaws
Four walking legs
0
0
0
1
1
1
Turtle
Four walking legs
Amniotic (shelled) egg
0
0
0
0
1
1
Hair
0
0
0
0
0
1
Amniotic egg
(a) Character table
Leopard
Hair
(b) Phylogenetic tree
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Fig. 26-UN5
Practicing Outgroup Comparisons
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Maximum Parsimony and Maximum Likelihood
• Systematists can never be sure of finding the
best tree in a large data set.
• They narrow possibilities by applying two
important phylogenetic principles:
– the principle of maximum parsimony;
– and the principle of maximum likelihood
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 26-14
Human
Mushroom
Tulip
0
30%
40%
0
40%
Human
Mushroom
0
Tulip
(a) Percentage differences between sequences
15%
5%
5%
15%
15%
10%
20%
25%
Tree 1: More likely
Tree 2: Less likely
(b) Comparison of possible trees
Phylogenetic Trees as Hypotheses
• The best hypotheses for phylogenetic trees fit
the most data: morphological, molecular, and
fossil record evidence.
• Phylogenetic bracketing allows us to predict
features of an ancestor from features of its
descendants.
• This has been applied to infer features of
dinosaurs from their descendants: birds and
crocodiles.
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Fig. 26-16
Lizards
and snakes
Crocodilians
Common
ancestor of
crocodilians,
dinosaurs,
and birds
Ornithischian
dinosaurs
Saurischian
dinosaurs
Birds
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Fig. 26-17
Front limb
Hind limb
Eggs
(a) Fossil remains of Oviraptor
and eggs
(b) Artist’s reconstruction of the dinosaur’s posture
New information continues to revise our understanding of the tree
of life.
•
Taxonomy is flux and constantly changing in the light of new data.
•
The most recently adopted classification for our tree of life is the three domain
system, which includes Bacteria, Archaea, and Eukarya. This system arose
from the finding that there are two distinct lineages of prokaryotes.
•
As we gain more tools for analysis, earlier ideas about evolutionary
relatedness are changed, and so taxonomy, too, continues to evolve.
Characteristic
Bacteria
Archaea
Eukarya
Nuclear Envelope
No
No
Yes
Membraneenclosed
Organelles
No
No
Yes
Introns
No
Yes
Yes
Histone Proteins
No
Yes
Yes
Circular
Chromosomes
Yes
Yes
No
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Revisiting the Central Ideas
•
Phylogenetic trees and cladograms are graphical representations
(models) of evolutionary history that can be tested.
•
Phylogenetic trees and cladograms can represent traits that are either
derived or lost due to evolution.
•
Phylogenetic trees and cladograms illustrate speciation that has
occurred, in that relatedness of any two groups on the tree is shown by
how recently two groups had a common ancestor.
•
Phylogenetic trees and cladograms can be constructed from
morphological similarities of living or fossil species, and from DNA and
protein sequence similarities – by employing computer programs that
have sophisticated ways of measuring and representing relatedness
among organisms.
•
Phylogenetic trees and cladograms are dynamic – constantly being
revised based on current and emerging knowledge.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings