Transcript Unit 5 (ch 15)

BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 15
Tracing Evolutionary History
Modules 15.1 – 15.5
From PowerPoint® Lectures for Biology: Concepts & Connections
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Are Birds Really Dinosaurs with Feathers?
• Did birds evolve from dinosaurs?
• Evolutionary biologists investigate this question
by looking at the fossil record
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• The fossil of the earliest
known bird,
Archeaopteryx,
was discovered in 1861
• Fossils of
dinosaurs with
feathers may
support the birddinosaur theory
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Divergent Evolution
Similar species develop different adaptations to
different environments
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Coevolution
• Two or more species adapting to each other
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Rate of Evolution Slow and Steady or in Spurts?
Gradualism – the idea that small changes build
up slowly over time to produce large changes.
Expectations – many intermediate “missing
link” fossils
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Punctuated Equilibrium
The idea that populations go through periods of
stability followed by short periods of rapid
change.
Expectations – fewer intermediate fossils
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EARTH HISTORY AND MACROEVOLUTION
15.1 The fossil record chronicles macroevolution
• Macroevolution consists of the major changes
in the history of life
– The fossil record chronicles these changes,
which have helped to devise the geologic time
scale
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Figure 15.1
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Figure 15.1
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Figure 15.1
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Figure 15.1
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Figure 15.1
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Figure 15.1
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15.2 The actual ages of rocks and fossils mark
geologic time
• The sequence of fossils in rock strata indicates
the relative ages of different species
• Radiometric dating can gauge the actual ages of
fossils
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Dating
How do scientists determine the relative age of a
fossil?
Stratification
Radiometric dating
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Stratification
The deeper strata (layers) were deposited first.
Fossils found in lower layers are older than in
higher layers.
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Radiometric Dating
Isotopes – atoms with a different mass than
usual
Half life – the time required for half of the
isotopes to decay.
Carbon 14 – half life 5730 yrs
Potassium 40 – half life 1.25 billion years
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C-14 isotope levels.
Expect 100 g of C-14 in a fresh sample,
A. Remains have 50 g.
½ of amount = one half-life 5,730 years old
B. Remains have only 25 g
¼ of amount or ½ of ½ = 2 half-lives 11,460
years old
C-14 Limited to about 50,000 years
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15.3 Continental drift has played a major role in
macroevolution
• Continental drift is the slow, incessant
movement of Earth’s crustal plates on the hot
mantle
Eurasian
Plate
North
American
Plate
African
Plate
Pacific
Plate
Nazca
Plate
South
American
Plate
Split
developing
Indo-Australian
Plate
Antarctic Plate
Edge of one plate being pushed over edge of
neighboring plate (zones of violent geologic events)
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Figure 15.3A
Continental Drift
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India
South
America
MESOZOIC
Antarctica
PALEOZOIC
– Separation of
continents caused the
isolation and
diversification of
organisms
Eurasia
Africa
Millions of years ago
– Continental mergers
triggered extinctions
CENOZOIC
• This movement has
influenced the distribution
of organisms and greatly
affected the history of life
Laurasia
Figure 15.3B
LungFish
• http://www.google.com/#hl=en&sugexp=les%
3B&gs_rn=4&gs_ri=psyab&gs_mss=archeaopteryx&pq=archaeopteryx
&cp=5&gs_id=9x&xhr=t&q=lungfish&es_nrs=
true&pf=p&sclient=psyab&oq=lungf&gs_l=&pbx=1&bav=on.2,or.r_gc
.r_pw.r_qf.&bvm=bv.42965579,d.b2I&fp=dcb
7caf6882243e1&biw=1351&bih=652
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• Continental drift explains the distribution of
lungfishes
– Lungfishes evolved when Pangaea was intact
Figure 15.3C
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NORTH
AMERICA
ASIA
EUROPE
AFRICA
SOUTH
AMERICA
AUSTRALIA
= Living lungfishes
= Fossilized lungfishes
Figure 15.3D
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15.4 Connection: Tectonic trauma imperils local
life
• Plate tectonics, the movements of Earth’s
crustal plates, are also associated with
volcanoes and earthquakes
– California’s
San Andreas
fault is a
boundary
between two
crustal plates
San Andreas fault
San Francisco
Santa Cruz
Los Angeles
Figure 15.4A
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• By forming new islands, volcanoes can create
opportunities for organisms
– Example: Galápagos
• But volcanic activity can also destroy life
– Example: Krakatau
Figure 15.4B, C
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15.5 Mass extinctions were followed by
diversification of life-forms
• At the end of the Cretaceous period, many lifeforms disappeared, including the dinosaurs
– These mass extinctions may have been a result of
an asteroid impact or volcanic activity
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?
Cretaceous
extinctions
90 million years ago
80
70
65
60
Figure 15.5
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• Every mass extinction reduced the diversity of
life
– But each was followed by a rebound in diversity
– Mammals filled the void left by the dinosaurs
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15.6 Key adaptations may enable species to
proliferate after mass extinctions
• Adaptations that have evolved in one
environmental context may be able to perform
new functions when conditions change
– Example: Plant
species with
catch basins, an
adaptation to dry
environments
Figure 15.6
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15.7 “Evo-devo:” Genes that control development
play a major role in evolution
• “Evo-devo” is a field that combines
evolutionary and developmental biology
• Major adaptations may arise rapidly if
mutations occur in genes that control an
organism’s early development
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• Paedomorphosis, the retention of juvenile
characteristics in the adult, seems to have
played a role in human evolution
Figure 15.7A, B
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Chimpanzee fetus
Chimpanzee adult
Human fetus
Human adult
• Stephen Jay Gould argued that there was a
connection between our juvenile physical traits
and our long period of dependency
– The youthful features of Mickey Mouse elicit
affectionate, parental responses
Figure 15.7C
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15.8 Evolutionary trends do not mean that
evolution is directed toward a goal
• Evolutionary trends may reflect unequal
speciation or survival of species on a branching
evolutionary tree
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Figure 15.8
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15.9 Phylogenetic trees strive to represent
evolutionary history
• Phylogeny is the evolutionary history of a group
of organisms
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Cactus
ground finch
Medium
ground finch
Large
ground finch
Small
Large cactus
ground finch ground finch
Small
tree finch
Vegetarian
finch
Medium
tree finch
Large
tree finch
Woodpecker
finch
Mangrove
finch
Green
Gray
warbler finch warbler finch
Sharp-beaked
ground finch
Seed
eaters
Cactus flower
eaters
Bud
eaters
Ground finches
Insect
eaters
Tree finches
Warbler finches
Common ancestor from
South America mainland
Figure 15.9
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Molecular Clocks
• A molecular clock compares the similarity in a
certain gene to see who related more closely
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SYSTEMATICS AND PHYLOGENETIC
BIOLOGY
15.10 Systematists classify organisms by phylogeny
• Reconstructing phylogeny is part of systematics
– the study of biological diversity and
classification
• Taxonomists assign a two-part name to each
species
– The first name, the genus, covers a group of
related species
– The second name refers to a species within a
genus
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Taxonomy
• Taxonomy – the classification of living things
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Classification of Living Things
Carol Linnaeus – (1707-1778)
Genus species
Binomial nomenclature
Bi – 2
nom – name
nomenclature – naming
Canis lupus – gray wolf
Latin – universal language of scholars
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• http://www.nhm.ac.uk/nature-online/scienceof-naturalhistory/biographies/linnaeus/index.html
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Hierarchy
Address
Planet - Earth
Continent – North America
Country – United States of America
State - Kansas
County - Rush
Town - LaCrosse
Street - Washington
number - 400
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Hierarchy of Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
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Remembering the order
Kingdom
King
Phylum
Phillip
Class
Came
Order
Over
Family
From
Genus
Great
Species
Spain
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Taxonomy of the Grizzly
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• Genera are grouped into progressively larger
categories
Table 15.10
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• Taxonomists often debate the particular
placement of organisms in categories as they
strive to make their categories reflect
evolutionary relationships
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Felis
catus
(domestic
cat)
Mephitis
mephitis
(striped
skunk)
Lutra
lutra
(European
otter)
GENUS
Felis
Mephitis
Lutra
FAMILY
Felidae
SPECIES
ORDER
Mustelidae
Canis
familiaris
(domestic
dog)
Canis
lupus
(wolf)
Canis
Canidae
Carnivora
Figure 15.10
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15.11 Homology indicates common ancestry, but
analogy does not
• Homologous structures are evidence that
organisms have evolved from a common
ancestor
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15.11 Homology indicates common ancestry, but
analogy does not
• In contrast, analogous similarities are evidence
that organisms from different evolutionary
lineages have undergone convergent evolution
– Their resemblances have resulted from living in
similar environments
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Convergent Evolution
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• California ocotillo and allauidia of Madagascar
Figure 15.11
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15.12 Molecular biology is a powerful tool in
systematics
• Systematists increasingly use molecular
techniques to
– classify
organisms
Human
Chimpanzee
Gorilla
Orangutan
– develop
phylogenetic
hypotheses
Figure 15.12B
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• A phylogenetic tree based on molecular data
Brown bear
Polar
bear
Asiatic
black
bear
American
black
bear
Sun
bear
Sloth
bear
Spectacled Giant
panda
bear
Lesser
Raccoon panda
Miocene
Pleistocene
Pliocene
Oligocene
Ursidae
Procyonidae
Common ancestral
carnivorans
Figure 15.12A
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15.13 Systematists attempt to make classification
consistent with phylogeny
• Homologous features are used to compare
organisms
• Cladistic analysis attempts to define
monophyletic taxa
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Cladogram
• A diagram that shows the relationships among
members of a group
hair
Preorbital fenestra
Amniotic egg
4 limbs
Bony skeleton
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vertebrae
Derived Character
• A trait that appears in the newer members of a
group, but not the older members
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TAXA
Outgroup
(Reptiles)
Eastern box
turtle
Ingoup
(Mammals)
Duck-billed
platypus
Red kangaroo North American
beaver
CHARACTERS
Long gestation
Gestation
Hair, mammary glands
Vertebral column
Long gestation
3
Gestation
2
Hair, mammary glands
1
Vertebral column
Figure 15.13A
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• Cladistic analysis is often a search for the
simplest hypotheses about phylogeny
– Phylogenetic tree
according to
cladistic analysis
– Phylogenetic tree
according to
classical
systematics
Lizards
Lizards
Snakes
Snakes
Crocodiles
Crocodiles
Birds
Birds
Figure 15.13B, C
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THE DOMAINS OF LIFE
15.14 Arranging life into kingdoms is a work in
progress
• For several decades, systematists have classified
life into five kingdoms
MONERA
PROTISTA
PLANTAE
Earliest
organisms
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FUNGI
ANIMALIA
Figure 15.14A
• A newer system recognizes two basically
distinctive groups of prokaryotes
– The domain Bacteria
– The domain Archaea
• A third domain,
the Eukarya,
includes all
kingdoms of
eukaryotes
BACTERIA
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ARCHAEA
EUKARYA
Earliest
organisms
Figure 15.14B
Domain Bacteri
a
Achaea
Eukarya
Kingdom Eubacter Archae
ia
bacteria
Protista
Fungi
Plantae
Animalia
Nucleus
Yes
Yes
Yes
Yes
Multicell No
No
ular/
Specializ
ed cells
Cell wall
Pseudo
composit Peptidog murein
ion
lycon
No
Yes
Yes
Yes
---------
Chitin
Cellulose
None
Auto
Both
Heterotr
oph
Both
Hetero
Auto
Hetero
No
No
Both
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