biology...structural and functional evidence supports the relatedness of all domains....

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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

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.


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.


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.


Fig. 26-21

Fungi

EUKARYA

Trypanosomes

Green algae Land plants

Red algae

Forams Ciliates

Dinoflagellates

Diatoms

Animals

Amoebas Cellular slime molds

Leishmania

Euglena

Green nonsulfur bacteria

Thermophiles

Halophiles

Methanobacterium

Sulfolobus

ARCHAEA

COMMON ANCESTOR

OF ALL LIFE

BACTERIA

(Plastids, including chloroplasts)

Green sulfur bacteria

(Mitochondrion)

Cyanobacteria

Chlamydia

Spirochetes


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)


Fig. 26-UN9

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.


Structural evidence supports the relatedness of all eukaryotes.


1. Cytoskeleton

2. Membrane-bound Organelles

3. Endomembrane Systems

4. Linear Chromosomes


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

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.


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.


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.

Fig. 26-4 Species

Canis lupus

Pantherapardus

Taxidea taxus

Lutra lutra

Canis latrans

Order Family Genus

Carn

ivo

ra

Felid

ae

Mu

ste

lidae

Can

idae

Can

is

Lu

tra

Taxid

ea

Pan

thera

Fig. 26-2


Fig. 26-5

Sister taxa

ANCESTRAL LINEAGE

Taxon A

Polytomy Common ancestor of taxa A–F

Branch point

(node)

Taxon B

Taxon C

Taxon D

Taxon E

Taxon F


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.


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.


– Number of heart chambers in animals

– Absence of legs in some sea mammals


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.


Lost Traits – Illustrative Example


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


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

Fig. 26-7


• 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.

Sorting Homology from Analogy

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!


Fig. 26-11

TAXA

Le

op

ard

Tu

na

Vertebral column

(backbone)

Hinged jaws

Four walking legs

Amniotic (shelled) egg

Hair

(a) Character table

Hair

Hinged jaws

Vertebral column

Four walking legs

Amniotic egg

(b) Phylogenetic tree

Salamander

Leopard

Turtle

Lamprey

Tuna

Lancelet

(outgroup)

0

0 0

0

0

0

0 0

0

0

0 0

0 0 0 1

1 1

1 1 1

1

1 1

1

1

1 1

1 1

Performing Outgroup Comparisons


Fig. 26-UN5

Practicing Outgroup Comparisons


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

Fig. 26-14

Human

15%

Tree 1: More likely Tree 2: Less likely

(b) Comparison of possible trees

15% 15%

5%

5%

10%

25% 20%

40%

40%

30% 0

0

0

(a) Percentage differences between sequences

Human Mushroom

Mushroom

Tulip

Tulip


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.


Fig. 26-16

Common ancestor of crocodilians, dinosaurs, and birds

Birds

Lizards and snakes

Crocodilians

Ornithischian dinosaurs

Saurischian dinosaurs

Fig. 26-17

Eggs

Front limb

Hind limb

(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

Membrane-

enclosed

Organelles

No No Yes

Introns No Yes Yes

Histone Proteins No Yes Yes

Circular

Chromosomes

Yes Yes No


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.

biology...structural and functional evidence supports the relatedness of all domains....

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