BIOLOGY
Chapter 15: pp. 264 - 282
10th Edition
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Dalmatian
Boston terrier
Irish wolfhound
Wolf
Scottish terrier
Beagle
Red chow
Shetland sheepdog
Shih Tzu
Sylvia S. Mader
Darwin & Evolution
Bloodhound
Russian
silver fox
English sheepdog
Chihuahua
(Wolf): © Gary Milburn/Tom Stack & Associates; (Irish wolfhound): © Ralph Reinhold/Index Stock Imagery; (Boston terrier): © Robert Dowling/Corbis;
(Dalmation): © Alexander Lowry/Photo Researchers, Inc.; (Shih tzu): © Bob Shirtz/SuperStock; (Bloodhound): © Mary Bloom/Peter Arnold, Inc.; (Scottish
terrier): © Carolyn A. McKeone/Photo Researchers, Inc.; (Beagle): © Tim Davis/Photo Researchers, Inc.; (Red chow): © Jeanne W hite/Photo Researchers,
Inc.; (Shetland sheepdog): © Ralph Reinhold/Index Stock Imagery; (English sheepdog): © Yann Arthus-Bertrand/Corbis; (Chihuahua): © Kent & Donna
Dannen/Photo Researchers, Inc.; (Fox): © Steven J. Kazlowski/Alamy
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor
Copyright © The McGraw Hill Companies Inc. Permission required for reproduction or display
1
Outline

History of Evolutionary Thought
 Darwin’s Theory of Evolution




Earth very old
Descend with change from a common ancestor
Adaptation to a changing environment
The Evidence of Evolution




Fossil
Biogeographical
Anatomical
Biochemical
2
History of Evolutionary Thought

Prior to Darwin
View of nature determined by deep-seated
beliefs
 Held to be intractable truths
 Biology thought had slowly begun to accept

Various ideas of evolution
 Similarities between living things reflect recent
common ancestry
 Dissimilarities between living things reflect ancient
common ancestry

3
Voyage of the HMS Beagle
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c
b
Great
Britain
North
America
PACIFIC
OCEAN
d
Europe
ATLANTIC
OCEAN
Africa
Galápagos
Islands f,g
INDIAN
OCEAN
South
America
e
b
Australia
d
c
Tasmania
a.
e
New
Zealand
Tierra del Fuego
f
g
b: © Wolfgang Kaehler/Corbis; c: © Luiz C. Marigo/Peter Arnold; d: © Gary J. James/Biological Photo Service; e: © Charles Benes/Index Stock Imagery; f: © Galen
Rowell/Corbis; g: © D. Parer & E. Parer-Cook/Ardea
4
Evolutionary Thought before Darwin
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a.
b.
a: © Joseph H. Bailey/National Geographic Image Collection; b: © Daryl Balfour/Photo Researchers, Inc.
5
Mid-Eighteenth Century

Taxonomy matured during mid-eighteenth
century

Linnaeus believed in:
The fixity of species
 That each species had:




He developed the binomial system of nomenclature


An ideal structure and function, and
A place in the scala naturae (scale of complexity)
System of classification for living things
Count Buffon:
Wrote 44-volume catalog of all known plants and
animals
 Suggested descent with modification

6
Late Eighteenth Century

Cuvier:

First to use comparative anatomy to develop a
system of classification

Founded Paleontology

Proposed Catastrophism

Local catastrophes in past had caused later strata
to have a new mix of fossils

After each catastrophe, the region was repopulated
by species from surrounding areas
7
Late Eighteenth Century

Lamarck:

First biologist to:





Propose evolution
Link diversity with environmental adaptation
Concluded more complex organisms are descended
from less complex organisms
Proposed inheritance of acquired characteristics –
Lamarckianism
Charles Lyell:


Earth is subject to slow but continuous cycles of
erosion and uplift
Proposed uniformitarianism, rates and processes of
change are constant
8
Darwin’s Theory of Evolution
Geological observations consistent with
those of Hutton & Lyell
 Biogeographical observations:

The study of the geographic distribution of life
forms on earth
 Darwin saw similar species in similar habitats;
 Reasoned related species could be modified
according to the environment

9
Charles Darwin at 31
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© Carolina Biological/Visuals Unlimited
10
A Glyptodont and a Giant Sloth
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a. Glyptodon
b. Mylodon
11
Biogeography


Biogeography is the study of the range and geographic
distribution of life-forms on Earth.
Darwin compared South American animals to those with
which he was familiar.


Instead of rabbits, he found the Patagonian hare in the grasslands
of South America. The Patagonian hare has long legs and ears
but the face of a guinea pig.
Did the Patagonian hare resemble a rabbit because the
two types of animals were adapted to the same type of
environment? Both animals ate grass, hid in bushes, and
moved rapidly using long hind legs. Did the Patagonian
hare have the face of a guinea pig because of common
descent with guinea pigs?
12
The European Hare (face only) and the
Patagonian Hare
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Lepus europaeus
Dolichotis patagonium
(European hare): © WILDLIFE/Peter Arnold, Inc.; (Patagonian hare): © Juan & Carmecita
Munoz/Photo Researchers, Inc.
13
Galápagos Islands

Tortoises
Darwin observed tortoise neck length varied
from island to island
 Proposed that speciation on islands correlated
with a difference in vegetation


Finches
Darwin observed many different species of
finches on various islands
 Speculated they could have descended from a
single pair of mainland finch

14
Galápagos Tortoises, Geochelone
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a.
b.
a: © Kevin Schafer/Corbis; b: © Michael Dick/Animals Animals/Earth Scenes
15
Natural Selection and Adaptation
Individuals have heritable variations
 More individuals produced each generation
than environment can support
 Some individuals have adaptive
characteristics

Enables increased survival and reproduction
 Increasing proportion of succeeding
generations will have these characteristics


Populations become adapted to their local
environment through change in individuals
16
Variation in a Population
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© Lisette Le Bon/SuperStock
17
Organisms Have Inheritable Variations


Darwin emphasized that individuals from a
population vary in their:

Functional characteristics

Physical characteristics

Behavioral characteristics
Proposed that these variations:

Are essential

Allow adaptation to the environment over time
18
Artificial Selection of Animals

All dogs are descended from the gray wolf

Began to be domesticated about 14,000 years
ago.

Process of diversification has been rapid:

The wolves under domestication were separated
from other wolves.

Each human tribe selected for whatever traits
appealed to them.
19
Artificial Selection of Animals
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Dalmatian
Boston terrier
Irish wolfhound
Wolf
Scottish terrier
Red chow
Shih Tzu
Bloodhound
Beagle
Shetland sheepdog
English sheepdog
Russian
silver fox
Chihuahua
(Wolf): © Gary Milburn/Tom Stack & Associates; (Irish wolfhound): © Ralph Reinhold/Index Stock Imagery; (Boston terrier): © Robert
Dowling/Corbis; (Dalmation): © Alexander Lowry/Photo Researchers, Inc.; (Shih tzu): © Bob Shirtz/SuperStock; (Bloodhound): © Mary
Bloom/Peter Arnold, Inc.; (Scottish terrier): © Carolyn A. McKeone/Photo Researchers, Inc.; (Beagle): © Tim Davis/Photo Researchers,
Inc.; (Red chow): © Jeanne White/Photo Researchers, Inc.; (Shetland sheepdog): © Ralph Reinhold/Index Stock Imagery; (English
sheepdog): © Yann Arthus-Bertrand/Corbis; (Chihuahua): © Kent & Donna Dannen/Photo Researchers, Inc.; (Fox): © Steven J.
Kazlowski/Alamy
20
Artificial Selection of Plants


Following vegetables are derived from one
species:

Chinese cabbage,

brussels sprouts, and

kohlrabi.
Darwin described artificial selection as a
model by which to understand natural
selection.
21
Artificial Selection of Plants
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Chinese cabbage,
Chinensis group
Brussel sprouts,
Gemmifera group
Kohlrabi,
Gongylodes group
Wild mustard
(Cabbage, Brussel sprouts, kohlrabi): Courtesy W. Atlee Burpee Company; (Mustard): © Jack
Wilburn/Animals Animals/Earth Scenes;
22
Natural Selection

Darwin’s natural selection hypothesis was
based on:

Observation of tortoises and finches on the
Galápagos Islands.
23
Natural Selection

13 species of finches have a beak adapted to a
particular way of life.

Heavy beak suited to a diet of large seeds

Beak of the warbler-finch is suited to feeding on insects

Longer beak, somewhat decurved, and the split tongue suited to
probing cactus for seeds
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a. Geospiza magnirostris
b. Certhidea olivacea
c. Cactornis scandens
a: © Adrienne T. Gibson/Animals Animals/Earth Scenes; b: © Joe McDonald/Animals Animals/Earth Scenes; c:
© Leonard Lee Rue/Animals Animals/Earth Scenes;
24
Beak Depth
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Beak Depth
wet year
dry year
dry year
dry year
medium
ground finch
1977
1980
1982
1984
25
Organisms Differ in Fitness

Fitness is the relative reproductive success
of an individual
The most-fit individuals in a population capture
a disproportionate share of goodies
 Interactions with the environment determine
which individuals reproduce the most


Adaptation
Changes that help a species become more
suited to its environment
 Product of natural selection

26
Evidence for Evolution

Evidence supports common descent.
Fossils Evidence
 Biogeographical Evidence


Anatomical Evidence

Biochemical Evidence
27
Evidence for Evolution: Fossil Record


Fossil evidence

Fossils record the history of life from the past

Document a succession of life forms from the
simple to the more complex

Sometimes the fossil record is complete
enough to show descent from an ancestor
Transitional fossils are a common
ancestor for two different groups of
organisms

It allows to trace the descent of organisms
28
Transitional Fossils
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head
wing
tail
feet
wing
a. Archaeopteryx
fossil
reptile characteristics
bird characteristics
feathers
teeth
tail with vertebrae
claws
b.
a: © Jean-Claude Carton/Bruce Coleman Inc.; b: © Joe Tucciarone
29
Ancestor to Whales
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30
Evidence for Evolution: Biogeographical

Distributions of plants and animals across
earth

Consistent with origin in one locale and
then spread to accessible regions

Hypothesis that different mix of plants and
animals would be expected whenever

Geography separates:

Continents, islands, seas, and so on.
31
Biogeography
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Tasmanian wolf, Thylacinus, now extinct, was a
nocturnal carnivore that inhabited deserts and plains.
It resembles the placental grey wolf.
Sugar glider, Petaurus breviceps, is a tree-dweller
and resembles the placental flying squirrel.
The Australian wombat, Vombatus, is
nocturnal and lives in burrows. It resembles
the placental woodchuck.
Kangaroo, Macropus, is an herbivore that
inhabits plains and forests. It resembles the
placental Patagonian cavy of South America.
The Australian native cat, Dasyurus, is a
carnivore and inhabits forests. It resembles
the placental wild cat.
(Sugar glider): © ANT Photo Library/Photo Researchers, Inc.; (Tasmanian wolf): © Tom McHugh/Photo Researchers, Inc.; (Wombat): © Photodisc Blue/Getty; (Dasyurus): © Tom McHugh/Photo Researchers, Inc.; (Kangaroo): © George
Holton/Photo Researchers, Inc.
32
Evidence for Evolution: Anatomical

Vertebrate forelimbs:




Homologous - All contain the same sets of bones in
similar ways
Yet they are modified extensively to meet various
adaptive needs
Darwin interpreted this as support for a hypothesis of
common descent
Embryological development



All vertebrate embryos have:
A postanal tail and
Paired pharyngeal (gill) pouches
33
The Evidence of Evolution: Anatomical

Homologous Structures:



Analogous Structures:




Anatomically similar because they are inherited from a
common ancestor
May be functionally similar or not
Serve the same function
Not constructed similarly
Do not share a common ancestor
Vestigal Structures:


Fully-developed anatomical structures
Reduced or obsolete function
34
Significance of Homologous Structures
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bird
humerus
ulna
radius
metacarpals
phalanges
bat
whale
cat
horse
human
35
Significance of Developmental Similarities
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fish
salamander
tortoise
chick
pharyngeal
pouches
human
postanal
tail
36
Biochemical Evidence


Almost all living organisms:

Use the same basic biochemical molecules

Utilize same DNA triplet code

Utilize same 20 amino acids in their proteins
DNA base-sequence differences:

When very similar, suggest recent common descent

When more different, suggest more ancient common
descent
37
Significance of Biochemical Differences
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yeast
moth
fish
turtle
duck
pig
monkey
human
Number of Amino Acid Differences
Compared to Human Cytochrome c
0
10
20
30
40
Cytochrome c is a small protein
that plays an important role
in the electron transport chain
within mitochondria of all cells
50
38
Review

History of Evolutionary Thought
 Darwin’s Theory of Evolution




Earth very old
Descend with change from a common ancestor
Adaptation to a changing environment
The Evidence of Evolution




Fossil
Biogeographical
Anatomical
Biochemical
39
BIOLOGY
Chapter 15: pp. 264 - 282
10th Edition
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Dalmatian
Boston terrier
Irish wolfhound
Wolf
Scottish terrier
Beagle
Red chow
Shetland sheepdog
Shih Tzu
Sylvia S. Mader
Darwin & Evolution
Bloodhound
Russian
silver fox
English sheepdog
Chihuahua
(Wolf): © Gary Milburn/Tom Stack & Associates; (Irish wolfhound): © Ralph Reinhold/Index Stock Imagery; (Boston terrier): © Robert Dowling/Corbis;
(Dalmation): © Alexander Lowry/Photo Researchers, Inc.; (Shih tzu): © Bob Shirtz/SuperStock; (Bloodhound): © Mary Bloom/Peter Arnold, Inc.; (Scottish
terrier): © Carolyn A. McKeone/Photo Researchers, Inc.; (Beagle): © Tim Davis/Photo Researchers, Inc.; (Red chow): © Jeanne W hite/Photo Researchers,
Inc.; (Shetland sheepdog): © Ralph Reinhold/Index Stock Imagery; (English sheepdog): © Yann Arthus-Bertrand/Corbis; (Chihuahua): © Kent & Donna
Dannen/Photo Researchers, Inc.; (Fox): © Steven J. Kazlowski/Alamy
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor
Copyright © The McGraw Hill Companies Inc. Permission required for reproduction or display
40