Download Chapter 5 Evolution

B IOLOGY 20 - C HAPTER 5
E VOLUTION
Nelson pages 132 – 173
1
C HAPTER 5.1
C LASSIFICATION OF
O RGANISMS
Nelson Reference: Pages 132-139
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3
C URRICULAR O UTCOMES :

20–B1.5k

Explain the fundamental principles of
taxonomy, i.e., domains, kingdoms and binomial
nomenclature
4
5.1 C LASSIFICATION OF O RGANISMS

10 million different species

Biological diversity is a sign of a healthy
ecosystem

Why?

Higher chance that some organisms will survive
changes in ecosystem
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T AXONOMIC S YSTEMS

Taxonomy


Science of classification
according to inferred
(presumed) relationships
among organisms
2 purposes
1.
Identify organisms
2.
Provide a basis for
recognizing natural
groupings of living things
True Facts about the Tarsier:
http://www.youtube.com/watch?v=6Jz0JcQYtqo&safe=activ
e&safety_mode=true
H ISTORY OF T AXONOMY
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
ARISTOTLE (384-322 BC)



1st person to attempt
classifying animals
divided them into groups: “blooded” and
“bloodless”
Linnaeus
(1707 –1778)

Created biological system of classification

Based on organisms’ physical and structural
features

The more features in common, the closer the
relationship among organisms
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B INOMIAL
NOMENCLATURE
Developed
by Linnaeus
A method of naming
organisms by using 2 names
Genus
alone
name – may appear
Species
name – never
appears alone
FYI
- To hand write – genus
name is capitalized, species
name is not; both are
underlined
FYI - To type – genus name
is capitalized, species name is
not; both are italicized
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ADVANTAGES TO BINOMIAL
NOMENCLATURE:

Indicates similarities in:

Anatomy

Evolutionary ancestry

“International language” – like the periodic
table!
L EVELS OF CLASSIFICATION

DOMAIN

KINGDOM

PHYLUM

CLASS

ORDER

FAMILY

GENUS

SPECIES
Levels
of
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Classification
Dandelion
Housefly
Human
kingdom
Plantae
Animalia
Animalia
phylum
Tracheophyta
Arthropoda
Chordata
class
Angiosphermae Insecta
Mammalia
order
Asterates
Diptera
Primates
family
Compositae
Muscidae
Hominidae
genus
Taraxacum
Musca
Homo
species
offincinale
domestica
sapiens
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A TRICK TO REMEMBER THE 8 TAXA :

Organisms are sorted into a hierarchical system, starting
with the broadest category—domain—and progressing
through kingdom, phylum, class, order, family, and genus to
the most specific category—species.
Danish
Ingeborg
King
Phillip
Came
Over
For
Green
Spinach
http://en.wikipedia.org/wiki/Philip_II_of_France


The classification system that is most commonly
used today has three DOMAINS and a number of
KINGDOMS.
The three Domains used to classify organisms are Bacteria,
Archaea, and Eukarya.
Bacteria
Eukarya
Archaea
• Prokaryotic, unicellular
organisms
• Lack a membranebounded nucleus
• Reproduce asexually
• Heterotrophic by
absorption
• Autotrophic by
chemosynthesis or by
photosynthesis
• Move by flagella
• Eurkaryotic, unicellular
to multicellular
organisms
• Membrane-bounded
nucleus
• Sexual reproduction
• Phenotypes and nutrition
are diverse
• Each kingdom has
specializations
• Flagella, if present, have
a 9 + 2 organization
• Prokaryotic, unicellular
organisms
• Lack a membranebounded nucleus
• Reproduce asexually
• Many are autotrophic by
chemosynthesis;
some are
heterotrophic by
absorption
• Unique rRNA base
sequence
• Distinctive plasma
membrane and cell
wall chemistry
3 DOMAINS , 6 KINGDOMS


Six Kingdoms.
The four in Eukarya are:




Plantae
Animalia
Protists
Fungi
D OMAIN : E UKARYA
Kingdom:
Protista
Plantae
Fungi
Animalia
(T ABLE 2 P .137)
FOR THE
6
KINGDOMS :
Kingdom
23
General
characteristics
1. Eubacteria  Simple
organisms
lacking nuclei
(prokaryote)
 Either
heterotrophs or
autotrophs
 All can
reproduce
asexually
 Live nearly
everywhere
Cell wall
Representative
organisms
 Often present
(contains
peptidoglycan –
made of
carbohydrate
and protein
subunits)
 Bacteria,
cyanobacteria
24
Kingdom
2.
Archaebacteria
General
characteristics
 Prokaryotic
 Heterotrophs
 Live in salt
lakes, hot
springs, animal
guts
Cell wall
 Present (does
not contain
peptidoglycan)
Representative
organisms
 Methanogens,
extreme
thermophiles,
extreme
halophiles
Kingdom
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General
characteristics
Cell wall
Representative
organisms
3. Protista
 Most are unicellular
(single – celled);
some are
multicellular;
eukaryotic
 Some are
autotrophs; some
heterotrophs; some
both
 Reproduce sexually
and asexually
 Live in aquatic or
moist habitats
Absent
Algae;
protozoans
Kingdom
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General
characteristics
4. Fungi
 Most are
multicellular
 All are
heterotrophs
 Reproduce
sexually and
asexually
 Most are
terrestrial
Cell wall
 Present
(made of
chitin)
Representative
organisms
 Mushrooms,
yeasts, bread
molds
27
Kingdom
General
characteristics
5. Plantae  All are
multicellular
 All are
autotrophs
 Reproduce
sexually and
asexually
 Most are
terrestrial
Cell wall
Representative
organisms
 Present (made of  Mosses, ferns,
conifers,
carbohydrates)
flowering plants
Kingdom
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General
characteristics
6. Animalia  All are
multicellular
 All are
heterotrophs
 Most
reproduce
sexually
 Live in
terrestrial
and aquatic
habitats
Cell wall
Absent
Representative
organisms
 Sponges,
worms,
lobsters,
starfish, fish,
reptiles,
birds,
mammals
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K INGDOM E UBACTERIA
Escherichia
coli
cyanobacteria
30
K INGDOM P ROTISTA
•Examples:
Algae,
slime-molds Euglena and
Paramecium
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K INGDOM F UNGI
• Examples: yeast and mushrooms
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J UST FOR F UN :
I NKY C AP F UNGI
Varieties of the inky cap mushroom
can be around the world. While
they are edible, ingesting alcohol
while eating the mushrooms
increases symptoms of nausea and
vomiting, and can even cause a
heart attack.
After the mushroom has released
its spores, the cap begins to liquify.
The thick black liquid that is seen
dripping from the edges is how the
inky cap got its name.
More info: http://bit.ly/1fWGufI
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K INGDOM P LANTAE
• Examples: mosses,
ferns, flowering plants
(e.g., buttercup)
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K INGDOM A NIMALIA
• Examples: humans and jellyfish
35
P HYLOGENY

History of evolution of a species or a group of
organisms
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P HYLOGENETIC TREE FOR HOMINIDS
D ICHOTOMOUS KEY

Can be helpful to sort organisms like these…
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D ICHOTOMOUS

A two – part key
used to identify
living things
 A series of
choices must
be made
 Each choice
leads to a new
branch of they
key
KEY
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D ICHOTOMOUS KEY EXAMPLE :
1.
Animal is taller than 1.5 meters ……………….. Go to 2
Animal is smaller than 1.5 meters …………….. Go to 3
2.
Animal is black and white …………………….. cow
Animal is brown ………………………………… horse
3.
Animal has feathers ……………………………. Chicken
Animals is pink with curly tail …………………… pig
http://dsc.discovery.com/videos/i-was-bitten-brown-recluse-spiderbite.html
43
T ASKS TO BE COMPLETED :

Read Chapter 5.1 in your textbook – pages
132-138

Complete Chapter 5.1 Questions: Page
139- #1-3, 5-7

Using a Classification Key – Investigation
5.1 – Textbook pages 162-163 – complete
procedure 1-2, and analysis a-d.
D IVERSITY IN THE P LANT
K INGDOM – A CLOSER L OOK
B IOLOGY 35 IB ONLY
46
D IVERSITY IN THE P LANT K INGDOM
•
The kingdom of the Plantae can be divided into
several phyla (DIVISIONS), some of which are:
•
Phylum Bryophyta: mosses and liverworts
•
Phylum Filicinophyta: ferns
•
Phylum Coniferophyta: coniferous plants
•
Phylum Angiospermatophyta: flowering plants
47
P HYLUM B RYOPHYTA
•
Live in damp areas and still require water for
reproduction
•
Small, single plants
•
Do not have vascular tissue or true roots,
leaves, or stems
•
Absorption of water takes place over all
surface areas
•
Mosses do not produce flowers
•
Male gamete is motile, swimming to the female
gamete
 The moss plant we see is the haploid gametophyte
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 It forms the haploid gametes which meet and a diploid

zygote it
formed
This zygote grows to form a diploid sporophyte, which sits on top of
the haploid gametophyte
 The diploid sporophyte
forms haploid spores by
meiosis
 The haploid spores can
grow out to form the
haploid gametophyte
 The gametophyte is the
dominant stage
 Bryophyta are
homosporous, producing
one kind of spore
49
•P HYLUM F ILICINOPHYTA
•
Vascular plant – they have a specialized transport
system: vascular bundles (xylem and phloem)
•
Have true roots, leaves, and stems
•
The fern plant we see is the diploid sporophyte
•
It forms haploid spores by meiosis
•
The haploid spores can grow out to form the haploid
gametophyte, the prothallus
 The prothallus is a small, flat structure, which produces haploid
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gametes
 The gametes meet and form a diploid zygote which can grow out
to form the diploid sporophyte
Filicinophyta are
heterosporous: they
form 2 kinds of spores
 Microspores form the
male gametophyte
 Megaspores form the
female gametophyte
 Filicinophyta do not
produce flowers
 Male gametes are motile
and swim to the female
gametophyte

51
P HYLUM C ONIFEROPHYTA
Vascular
plants with true roots,
leaves, and stems
Sporophyte
Gametes
is the dominant generation
are not motile
Heterosporous
•
Microspores are called pollen grains
•
Megaspores are called the embryo sac
Seeds
Plant
are not enclosed in an ovary
bears no fruit
Spores
Xylem
develop on cones
contains only tracheids, vessels are
missing; companion cells are absent from
phloem
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P HYLUM A NGIOSPERMOPHYTA
Vascular
plants with true roots,
leaves, and stems
Sporophyte
generation
Gametes
is the dominant
are not motile
Heterosporous
Spores
develop in flowers
Seeds
are enclosed in an ovary
which develops into a fruit after
fertilization
Xylem
contains vessels, phloem
contains companion cells
D IVERSITY IN THE A NIMAL
K INGDOM – A CLOSER L OOK
D IVERSITY IN THE A NIMAL
K INGDOM – A CLOSER
L OOK
Chapter 21 Zebra Book– Pages 370 - 374
P HYLUM P ORIFERA -
SPONGES

Sponges are a diverse group of sometimes
common types, with about 5000 species known
across the world. Sponges are primarily marine,
but around 150 species live in fresh water.

a system of pores and canals, through which
water passes. Water movement is driven by the
beating of flagellae, which are located on
specialized cells

They are supported by a skeleton made up of the
protein collagen and spicules, which may be
calcareous or siliceous, depending on the group of
sponges examined.

Sponges capture food (detritus particles,
plankton, bacteria) that is brought close by water
currents created by the flagellae. Food items are
taken into individual cells by phagocytosis, and
digestion occurs within individual cells.
P HYLUM C NIDARIA - CNIDARIANS

The Phylum Cnidaria includes such diverse forms as
jellyfish, hydra, sea anemones, and corals.

Aggressive predators that have specialized tissues for
hunting


Muscle like contractile cells organized into tenticles allowing
cnidarians to catch their prey

Cnidocytes = stinging cells containing coiled filaments with a
poison barb on the end – when cnidocyte touches prey, barb
lauched like harpoon

Have a nervous system that cooridanates the activities of the
cnidocytes and tentacles
Cnidarian bodies have two or sometimes three layers.

gastrovascular cavity has a single exterior opening that
serves as both mouth and anus. Often tentacles
surround the opening.
C NIDARIANS

CONTINUED …
Cnidarians have two basic body forms, medusa and polyp.

Medusae, such as adult jellyfish, are free-swimming

Polyps, in contrast, are usually sessile. They have
or floating. They usually have umbrella-shaped bodies
and tetramerous (four-part) symmetry. The mouth is
usually on the concave side, and the tentacles originate
on the rim of the umbrella.
tubular bodies; one end is attached to the substrate,
and a mouth (usually surrounded by tentacles) is found
at the other end. Polyps may occur alone or in groups of
individuals
P HYLUM P LATYHELMINTHES -
FLATWORMS

Flatworms are unsegmented, bilaterally
symmetrical worms that lack a coelom
(acoelomate) but that do have three germ layers.

Some forms are free living, others are
decomposers, but many are parasitic.

Sensory receptors and nerve ganglia are located
at the anterior end
T HREE
CLASSES OF FLATWORMS :
Turbellaria – live in oceans, lakes, ponds, moist places on
land
1.

Example – Planarians- found in freshwater – secrete a slime
track and beating cilia allow for movement

Digestive systems are incomplete – similar to cnidarians

Mouth in middle of body
2. T REMATODA

parasites commonly called flukes

Contain protective body coverings that prevent them from being
digested

Typically have two suckers to attach to host and suck nutrients

Cause schistosomiasis in humans – eggs clog arteries, cause allergic
reactions, well and damage to organs – “old disease” - found in
Egyptian mummies
3. C ESTODA

tapeworms- parasitic – live in digestive tracts of host

Do not have a mouth, digestive system, or sense organs but
do have a nervous and excretory system

Scolex – knob shaped head with hooks, suckers or both
P HYLUM A NNELIDA - SEGMENTED WORMS

The annelids include earthworms,
polychaete worms, and leeches. All
members of the group are to some
extent segmented, in other words,
made up of segments that are formed
by subdivisions that partially transect
the body cavity.

Segments each contain elements of
such body systems as circulatory,
nervous, and excretory tracts.

Fluid in coelom in earthworms serves as
a hydrostatic skeleton

Circular and longitudinal muscles relax
and contract in coordination with setae
to propel the earthworm forwards
P HYLUM M OLLUSCA
 Mollusks
include: snails, clams,
squids, octopuses
 Contain
a muscular foot that is
used from locomotion or
attachement

Contains mucus secreting cells
 Containt
a mantle – soft, outer
layer of their bodies, which for
most mollusks, produce a
protective shell
 Between
the mollusk’s foot and
mantle is the visceral mass
which contains most of the
internal organs
P HYLUM A RTHROPODA

Arthropods include an incredibly diverse group of taxa such
as insects, crustaceans, spiders, scorpions, and centipedes.

Arthropods are invertebrates that are bilaterally
symmetrical with segmented bodies

The body is covered with an exoskeleton made up primarily
of chitin (a tough polysaccharide)

Most segments have paired, jointed appendages (body
extensions like antennae or legs)

Most arthropods have a pair of compound eyes and one to
several simple ("median") eyes or ocelli; either or both kinds
of eyes may be reduced or absent in some groups
D IFFERENT C LASSIFICATIONS






















Kingdom Animalia (animals)
Eumetazoa (metazoans)
Bilateria (bilaterally symmetrical animals)
Phylum Orthonectida (orthonectids)
Phylum Rhombozoa (rhombozoans)
Deuterostomia (deuterostomes)
Phylum Chordata (chordates)
Phylum Hemichordata (hemichordates)
Phylum Echinodermata (echinoderms) Protostomia (protostomes)
Phylum Arthropoda (crustaceans, insects, spiders, and relatives)
Phylum Tardigrada (water bears)
Phylum Onychophora (velvet worms)
Phylum Kinorhyncha (kinorhynchs)
Phylum Loricifera (loriciferans)
Phylum Nematoda (nematodes)
Phylum Nematomorpha (gordian worms and horsehair worms)
Phylum Priapula (priapulans)
Phylum Cycliophora
Phylum Gnathostomulida (gnathostomulids)
Phylum Ctenophora (comb jellies)
Phylum Cnidaria (cnidarians)
Phylum Myxozoa (ciliated protozoans)
Phylum Placozoa
Phylum Porifera (sponges)
71
K INGDOM A NIMALIA
C ONTINUED
Lophotrochozoa
 Lophophorates (lophophorates)
 Phylum Brachiopoda (lamp shells)
 Phylum Bryozoa (bryozoans, ectoprocts, and moss animals)
 Phylum Phoronida (phoronids)
 Trochozoa
 Phylum Annelida (segmented worms)
 Phylum Mollusca (mollusks)
 Phylum Chaetognatha (arrow worms)
Phylum Entoprocta (entoprocts)
 Phylum Gastrotricha (gastrotrichs)
 Phylum Nemertea (proboscis worms)
Phylum Rotifera (rotifers)
Phylum Sipuncula (sipunculan worms)
Phylum Platyhelminthes (flatworms)
Ecdysozoa
C HAPTER 5.2
E VIDENCE OF A C HANGING
E ARTH
Nelson Reference: Pages 140-143
77
78
C URRICULAR O UTCOMES :

20–B2.4k


Summarize and describe lines of evidence to support
the evolution of modern species from ancestral forms,
i.e., fossil record, Earth’s history, embryology,
biogeography, homologous and analogous structures,
biochemistry
20–B2.1sts

Explain that scientific knowledge and theories develop
through hypotheses, the collection of evidence through
experimentation, observation and the ability to provide
explanations
79
5.2 E VIDENCE OF A C HANGING E ARTH

Types of evidence include:

Fossil records

Geographic distribution of species

Comparative anatomy

Embryology

Behavior

Plant and animal breeding

Biochemistry

Genetics
80
I.) E VIDENCE FROM FOSSILS

Paleontology

Study of fossils

250 000 fossil
species discovered

Fossilized:


Burrows,
footprints,
chemical remains
However, most
organisms do NOT
leave any evidence
81
F ORMATION OF FOSSILS

Hard parts of organisms

Teeth, shells, and
bones


Resist action of
weathering for long
periods of time, in dry
environments
Insects may become
entrapped in amber
(hardened gum given off
by trees)
82
F OSSILIZED AMBER
83
S OFT PARTS OF ORGANISMS

Impressions or imprints of
plants and animals

Tracks made in soft mud, and
fecal material of animals

Intracellular spaces of
skeletal material of animals or
plants

Replaced with mineral
matter

Silica, calcite, or iron
compounds
84
D ATING

THE PAST
Relative dating – deeper sedimentary rock
layers means formed earlier = older fossil!
85
A BSOLUTE D ATING - R ADIOACTIVE

Technique used to determine
age of a rock or fossil by
determining the rate at which
radioactive isotopes decay
 Oldest fossil is ~ 3.8 billion
years old
 Age of Earth is ~ 4.6 billion
years old
DATING
Fossil Record and Geological Time:
A closer look...
Geologists have
developed a
relative time
scale for dating
rocks and fossils
The geologic
time scale is a
series of major
and minor
divisions that
correspond to
major
evolutionary
events
87
4.6
BILLION YEARS IN ONE HOUR !
88
F INDINGS FROM FOSSIL EVIDENCE
Different species lived on Earth
at various times in past
 Very few of today’s species
were alive 1 million years ago
 Almost all are now extinct
2.
Complexity of living organisms
generally increases from most
distant past to present
 Progression from very simple
organisms to species of 
complexity
3.
Living species and their closely
related matching fossils live in
same geographic region
1.
M ISSING L INKS


Scientists at the
University of Oslo have
discovered “Ida,”
Aka. Darwinius masillae

A 47-million-year-old
fossil that has been
proclaimed the “missing
link” in connecting human
skeletal structure to
early mammals.

she has certain
undeniable human
characteristics such as
forward facing eyes and
even an opposable thumb.
19 May 2009
90
E VIDENCE FROM B IOGEOGRAPHY

Biogeography

Study of
geographic
distribution of
life on Earth
91
P LATE T ECTONICS


Explains changes in position of
continental land masses
Theory of plate tectonics




Explains how Earth changed from
a single supercontinent (225
million years ago), Pangea, to
present continents
Species older than 150 million
years old were on same continents
Species younger than 150 million
years old were on separate
continents
Thus, they developed AFTER
break up of Pangea
93
P ANGEA

Limited distribution of mammals


EXAMPLES :
Limited distribution of marsupials in Africa,
Australia, and South America
Amphibians and reptiles

Arose during time of supercontinent - are
widely distributed on practically all continents
94
S EE
ANYTHING INTERESTING ABOUT THIS
GRAPHIC ?
95
P LATE TECTONICS –
( JUST FOR FUN )

WHAT REALLY HAPPED !
http://www.youtube.com/watch?v=TzzGPfVx32M
&safety_mode=true
96
C RASH C OURSE B IOLOGY

http://www.youtube.com/watch?v=P3GagfbA2vo&
safety_mode=true
97
T ASKS TO BE C OMPLETED :

Read Chapter 5.2 in your textbook: Pages 140-143

Complete 5.2 Questions – Page 143 # 1-2

Optional - Evolution and Time Interactive Web Activity – PBS website

http://www.pbs.org/wgbh/evolution/educators/lessons/lesson3
/act1.html
5.3 E VIDENCE OF EVOLUTION
FROM BIOLOGY
Nelson Reference: Pages 144-149
98
99
5.3 E VIDENCE OF E VOLUTION FROM
B IOLOGY

Includes physical anatomy and genetic makeup of
organisms
100
E VIDENCE FROM ANATOMY

A comparison of anatomies of various organisms
suggests that organisms with similar structures
evolved from a common ancestor
101
H OMOLOGOUS STRUCTURES
Have
similar origin but different uses in
different species
Example:
Front
flipper of a dolphin and forelimb of a cat
102
A NALOGOUS STRUCTURES

Are similar in function and appearance but not
in origin

Examples

Wing of an insect and wing of a bird

Human eye and Octopus Eye

Shark and Dolphin Streamlined bodies
103
A NALOGOUS S TRUCTURES EXAMPLE :

Recall placental vs.
marsupial mammals
don’t share a common
ancestor until before
the breakup of Pangea

development of similar
adaptions from
unrelated species

Due to adaptation
to similar
environmental
conditions
104
E MBRYONIC DEVELOPMENT

During late 1800s

Scientists noted striking similarity
between embryos of different species

Many structures in an embryo are similar to
those found in common ancestors
View video clip –
Common Pasts,
Different Paths
105
Can you identify which embryo is the human, chicken,
fish, tortoise, hog, calf, salamander, or rabbit?
106
V ESTIGIAL FEATURES AND ANATOMICAL
ODDITIES

Vestigial features

Rudimentary structures with no useful function

Perhaps were once functional in an ancestor

Whale skeletons have vestigial hip and leg bones
107
M ORE
•
•
EXAMPLES OF VESTIGIAL STRUCTURES
human appendix, coccyx (tail bone), muscles which move the
ears
Are we descended from animals in which these structures were
useful?
From an old science text (now out of
print). This shows that tail on a human
baby.
This is not common but also not rare. The
tail is removed surgically.
108
II.) E VIDENCE FROM B IOCHEMISTRY


All organisms share similar DNA molecules and
certain proteins

Eg. Pig insulin used to be used to treat type I
diabetes

We now use genetically modified bacteria that
have the human insulin gene inserted into it!
Example: amino acid
sequencing between
human, rhesus monkey,
mouse, chicken, frog,
and lamprey

Differences reflect
degree of similarity
109
S IMILARITIES IN THE G ENETIC CODE

DNA (Deoxyribonucleic
acid)


Hereditary material
in cells
Each DNA molecule
contain many different
genes

Gene – a segment of
DNA that performs
a specific function
110
DNA C ODE IS U NIVERSAL !

Composed of 4 nucleotide bases
arranged in different sequences


Adenine (A), thymine (T),
cytosine (C), guanine (G)
DNA sequences from different
species that code for the same
protein vary in # and order of
nucleotides

Part of a Cow milk protein sequence of DNA:
AGTCCCCAAAGTGAAGGAGACTATGGTTCCTAAGCACAAG GAAATGCCCTTCC
111
E VIDENCE FROM A RTIFICIAL S ELECTION

Process of humans selecting and breeding
individuals with desired traits

Dramatic changes are produced in a species
over a relatively short period of time
112
A RTIFICIAL S ELECTION
113
A RTIFICIAL S ELECTION - DOGS
114
T ASKS TO BE COMPLETED

Read pages 144-149 of your textbook

Complete Chapter 5.3 Questions – Page 149 - #1-3

Optional: Lab Exercise 5.A – Evidence from Genetics – Page 147 –
complete letters

Optional: Internet Web Quest Assignment – Evidence of Evolution

http://www.pbs.org/wgbh/evolution/educators/lessons/lesson3
/act2.html
5.4 T HE M AKING
A CCOUNTING FOR
THE
Nelson Reference: 150-152
115
T HEORY –
E VIDENCE
OF A
116
C URRICULAR O UTCOMES :
20–B2.3k

Compare Lamarckian and Darwinian explanations
of evolutionary change
20–B2.1sts

Explain that scientific knowledge and theories
develop through hypotheses, the collection of
evidence through experimentation, observation
and the ability to provide explanations
117
5.4 T HE M AKING OF A T HEORY –
A CCOUNTING FOR THE E VIDENCE

Scientific theory

A model that
accounts for all of
the known
scientific
evidence

Plausible
explanation

May be altered or
modified as new
data is gained
118
119
E XAMPLE – C HANGING I DEAS OF WHAT OUR
EARLY ANCESTORS MAY OF LOOKED LIKE

Lucy recently underwent a
‘makeover’ due to newly
discovered fossils. Earlier
reconstructions showed Lucy,
who is an example of one of
Homo sapiens’ ancestors
Australopithecus afarensis,
with a cone-shaped thorax and
potbelly. In the last few
years, researchers have found
additional ribs and a new foot
bone of A. afarensis. The ribs
were curved, which translates
to a barrel-shaped thorax like
modern humans, while the foot
bone showed a distinct arch.
More about Australopithecus
afarensis:http://bit.ly/1eEQE
Cy; http://bit.ly/18WAUmq
120
W HAT
HAPPENED TO THE WOOLY
MAMMOTHS ?

The new evidence from over 300 mammoth remains strongly suggests that
the mammoth population decline happened 20,000 years ago, not 14,000
years ago as previously thought. This better correlates with the changing
climate than an influx in human hunters.
More info: http://bbc.in/15QgVvo
Photo credit: Science Photo Library
D EVELOPING T HEORIES ABOUT
HOW POPULATIONS C HANGE OVER
TIME ( EVOLVE )
121
122
L AMARCK ’ S
THEORY OF
A CQUIRED
CHARACTERISTICS

Presented 1st theory of evolution
that included a mechanism

Organisms had a “desire” or “force”
that led them to change for the
better

Organisms can produce new parts
or get rid of unwanted parts


Use and disuse of certain
structures would be passed on
to offspring
Organisms eventually adapted to
their environment
123
L AMARCKISM

Describes “inheritance of acquired
characteristics”

False concept of inheritance of features
acquired during an individual’s life
124
II.) D ARWIN ’ S THEORY

In 1831, a five – year voyage
on the ship, Beagle

Provided Darwin with
opportunity to study
diverse life forms

From South America to
South Sea Islands
125
Darwin – mid 1800’s
 Published the Origin of Species by Means of
Natural Selection based on his
investigations while on board the 5 year
world voyage aboard the Beagle
 Much of his evidence for the theory of
natural selection was his studies of the
finches of the Galapagos Islands (1000 km
west of Ecuador)
126
127
G ALAPAGOS I SLANDS : A
E COSYSTEM
UNIQUE
I SLAND
128
129
D ARWIN
AND OTHER CONTRIBUTING
SCIENTISTS

Malthus’ essay on populations


All species produce more
offspring than are able to
survive
 Thus, Darwin realized that
competition exists
Wallace’s paper sent to Darwin

Wallace traveled extensively

Independently arrived at the
same conclusions as Darwin
130
D ARWIN ’ S T HEORY OF N ATURAL S ELECTION
CONDENSED INTO 5 KEY POINTS !
1.

Overproduction
Number of offspring produced by a species is
greater than can survive and reproduce (from
Malthus’ Essay)
131
2. S TRUGGLE

FOR EXISTENCE
Organisms of the same species (and other
species) must compete for the same limited
resources
132
3. VARIATION

No two individuals are exactly alike (except identical twins).
Sexual reproduction creates variability in a population

Offspring inherit most of parent’s traits, but not all of them.
Some traits arise randomly (eg. by genetic mutation)

Eg. A genetic mutation in Africa has led to some individuals
being immune to AIDS

Eg. Silent crickets in Hawaii
133
4. S URVIVAL

OF THE FITTEST
The environment acts to select favorable traits
(not create them). Those with an advantage
survive and reproduce, increasing their numbers.
This is selection by nature, hence natural
selection
134
5. S PECIATION

Individuals do not change, populations change over
time. Accumulation of new traits over a long period
of time ---> population so different ---> new species.
Source: http://evolution.berkeley.edu/evosite/evo101/VBDefiningSpeciation.shtml
135
D ARWIN ’ S G IRAFFES … EXPLAIN
EVOLVED LONG NECKS

O

S

V

S

S
HOW THEY
136
L AMARCK VS . D ARWIN ’ S G IRAFFES
137
T ASKS
TO BE COMPLETED

Read Chapter 5.4 in Your textbook – Pages 150-152

Section 5.4 Questions – Page 152 - #1-2

Peppered Moth Case Study – Workbook

Optional: Survival of the Sneakiest Cartoon

Optional: Who was Charles Darwin? Internet Assignment
http://www.pbs.org/wgbh/evolution/educators/lessons/l
esson2/index.html
Section 5.2 Questions # 1-2 - answers
5.5 S OURCES OF I NHERITED
V ARIATION
139
140
C URRICULAR O UTCOMES
20–B2.1k

Explain that variability in a species results from
heritable mutations and that some mutations may
have selective advantage(s)
20–B2.2k

Discuss the significance of sexual reproduction to
individual variation in populations and to the
process of evolution
M UTATIONS
142
MUTATIONS

MUTATIONS are RANDOM CHANGES in DNA
-your DNA (your GENES) is what codes for every
structure in your body
-DNA is HEREDITARY
-Your DNA is ½ from Mom, ½ from Dad

Mutations can be “bad” (harmful)
-ex. sheep born without a uterus
-the ewe will not pass on her DNA
-this mutation has no advantage
B ENEFICIAL MUTATIONS

Mutations can be “good” (beneficial)
-ex. a cheetah is born with the ability to run faster
than the others
-helps it to survive; it gets more food!
-this mutation has a SELECTIVE ADVANTAGE
-this mutation likely WILL be passed on to it’s
offspring
House Fly
There is a mutation in house flies that
makes them resistant to the insecticide
DDT.
145
H YPERTRICHOSIS … HARMFUL ,
NEUTRAL MUTATION ?
BENEFICIAL OR

Hypertrichosis is also called “werewolf syndrome” or Ambras
syndrome, and it affects as few as one in a billion people; and in
fact, only 50 cases have been documented since the Middle Ages.

People with hypertrichosis have excessive hair on the shoulders,
face, and ears. Studies have implicated it to a rearrangement of
chromosome 8.
http://io9.com/10-unusual-genetic-mutations-in-humans-470843733
R ECALL
MUTATION CREATES VARIABILITY !

MUTATIONS = DIVERSITY!

Accumulation of mutations over 100’s or 1000’s of
years may lead to SPECIATION
-formation of a new species
Scientists look to Hawaii’s bugs for
clues to origins of biodiversity
One species of spider (Tetragnatha anuenue)
on the Big Island of Hawaii shows an
extraordinary diversity of color, that is
matched by genetic variability. This variability
seems to serve as the raw material for
subsequent divergence and formation of new
species over the course of tens or hundreds of
thousand years.
W HAT CAUSES MUTATIONS ?

environmental factors (chemicals, radiation, etc.)

spontaneous mistakes
- ex. when cells are copying their DNA (before
making new cells)
148
C HECK Y OUR U NDERSTANDING …
1.
What is a Mutation?
2.
Why are mutations important to the
survival of a species over time?
3.
What are causes of mutations?
Tasks to be Completed For Chapter 5.5

Read Pages 153-156 of your Text book

Complete #1-3 on page 156

Start Unit B Review – Page 170 #1-14
Key to Questions #1-3 on page 156

1. Darwin was unaware of the source of variation —
sexual reproduction and mutation.

2. Short-term variation is derived from the shuffling of
genetic combinations through sexual reproduction. Longterm variation in a population is achieved by the
introduction of new genes by mutation.

3. Indigenous populations had never been exposed to
these diseases, so their population did not contain large
numbers of people with resistance to these diseases. The
disease acts as a selecting agent. After several
generations of exposure, indigenous people have evolved
a resistance similar to that of the European settlers.
C HAPTER 5.6
S PECIATION AND E VOLUTION
151
152
C URRICULAR OUTCOMES :
20–B2.5k

Explain speciation and the conditions required for
this process
20–B2.6k

Describe modern evolutionary theories, i.e.,
punctuated equilibrium versus gradualism
153
5.6 S PECIATION AND E VOLUTION
I.) Speciation
Formation
of new species
Species
A
population of individuals who
are reproductively isolated
Not
capable of breeding with
individuals of other species under
natural conditions
154
A LLOPATRIC
SPECIATION
–
SPECIATION BY
REPRODUCTIVE ISOLATION
1.
A physical barrier separates a single interbreeding
population into 2 or more groups

Groups are isolated from each other

Any mutations that occur in these groups are
not shared with other populations

From large to small physical barriers

Mountain ranges, oceans, river channels,
canyons, dams, canals
155
2. N ATURAL
SELECTION WORKS ON
SEPARATED GROUPS INDEPENDENTLY

Results in inherited
differences in the 2
populations

I.e., populations
evolve independently

Differences in
selective pressures
will be greater the
more pronounced the
environmental
differences
156
3. In time, accumulated physical and / or
behavioral populations are pronounced
that groups cannot reproduce with each
other

If reunited, individuals of these 2 groups are not
sexually compatible

Thus, the formation of two or more distinct
species
Note: this is only for fun and there is no such thing as unicorns
157
OH
WAIT , THERE ARE UNICORNS !
B ETTER E XAMPLE : “D ARWIN ' S F INCHES ”
 They
became
different species,
of finch, as they
were
geographically
isolated from the
mainland, and over
time the food
source they were
best adapted to
(via their beak
variation)
distinguished
them from each
other = speciation.
159
P ART II.) R ATE OF E VOLUTION


Theory of
gradualism
theory that changes to
species happen at a slow,
steady pace
-would expect many fossils to
also show minor changes
over time
-this is not always the case...
often distinct species suddenly
appear...
The fossil record suggests whales
gradually evolved from land to water.
160
T HEORY OF PUNCTUATED EQUILIBRIUM

Proposed by Eldridge and Gould

3 assertions:
1.
Many species evolve rapidly in
evolutionary time
2.
Usually occurs in small isolated
populations

3.
Dr. Niles Eldridge
Intermediate fossils are
rare
After an initial burst of
evolution, species are well
adapted to their environment

They do not significantly
change over long periods of
time
Dr. Stephen Jay Gould
161
G RADUALISM VS .
PUNCTUATED EQUILIBRIUM
162
T ASKS T O B E C OMPLETED

Read Pages 157-161 in your textbook

Complete Section 5.6 Questions – Page 161 #1, 4-5

Optional: Web Activity – Lactose Intolerance and
Evolution – Page 158 Text

Web Activity – Peppered Moth Simulation – Page 161

Prepare for a Unit Exam!!!

Chapter 5 Review: Page 168-169 # 1-10

Unit B Review Pages 170-173 #2-3, 12-14, 36-37
Section 5.6 Questions – Page 161 #1, 4-5
1.
First, a physical barrier separates a single interbreeding population
into two or more groups that are reproductively isolated from each
other. Any mutations that occur in these isolated groups are not
shared with the entire population. Second, natural selection works
on the separated groups independently, resulting in inherited
differences in the two populations. In other words, the populations
evolve independently. Differences in selective pressures will be
greater if the populations experience pronounced differences in their
environments. Finally, over time, accumulated physical and/or
behavioural differences between the populations become so
pronounced that the groups, should they be reunited, would no
longer be sexually compatible. At this point, they have formed two or
more distinct species.
Section 5.6 Questions – Page 161 #1, 4-5
4.
According to the theory of gradualism, we would expect
to find many fossils that show small changes in species
over time. Instead, distinct species often appear abruptly
in the fossil record, and then little further change is seen
over very long periods of time.
O N A SIDE TOPIC …
165
166
D O EVOLUTIONIST SCIENTISTS SUGGEST THAT
HUMANS HAVE EVOLVED FROM MONKEYS OR APES ?
No!
So how did humans evolve? Who were our ancestors and
what did they look like?
167
W HO ARE OUR CLOSEST LIVING RELATIVES ? H OW
ARE WE RELATED TO MONKEYS , APES AND
GORILLAS ?
O UR EVOLUTIONARY J OURNEY WAS MUCH MORE
168
COMPLEX AND IS STILL DEBATED AMONG SCIENTISTS
TODAY
169
170
171
A PHYLOGENIC T REE FOR THE
E VOLUTION OF H UMANS
172
W HERE
N EWLY D ISCOVERED “ HOBBIT ”
INTO EVOLUTION OF HUMANS ?
DO THE
SPECIES FIT
173
H OW HUMANS POPULATED THE WORLD
174
H OW
DID THE EVOLUTION OF DIFFERENT
RACES OCCUR IN THE HUMAN POPULATION ?
175
T HE E VOLUTION VS .
C REATIONISM D EBATE
176
T HE S CIENCE / R ELIGION D ICHOTOMY
I T ’ S EITHER OR AND NOTHING IN BETWEEN ….
Atheist View
Creationist View
However, the spectrum of beliefs is actually much more
complicated in today’s society with a range of beliefs that fall
inbetween
D R , D R , D R .( NOT A TYPO ) D ENIS O. L AMOUREUX
177

Lamoureux's academic specialty focuses on the
modern origins controversy. In "Beyond the
'Evolution vs. Creation' Debate" he argues that
the simple either/or approach to origins
inhibits everyone from making informed
choices. He asserts that if the limits of both
conservative Christianity and evolutionary
biology are respected, then their relationship
is not only complementary, but also necessary.
This view of origins is known as Evolutionary
Creation. Concisely stated, it claims that the
Father, Son and Holy Spirit created the
universe and life through an ordained and
sustained evolutionary process.

Lamoureux holds three earned doctoral
degrees: dentistry, theology, and biology.

Lamoureux has developed a summarized table
of the spectrum of beliefs that exist
Chapter 5 Review

(Pages 168–169)

Part 1

1. D

2. C

3. D

4. B

5. D

6. D

7. C

8. 3, 2, 1, 4

9. 1, 4, 2, 3

10. 1, 4, 3, 2
Unit B Review

(Pages 170–173)

Part 1

2. D

3. C

12. D

13. 1, 3, 6, 7

14. 2, 4, 3, 1

36. (a) Lamarck would suggest that in reaching for food, giraffes stretched
their necks slightly. This acquired trait, a slightly longer neck (resulting from
stretching), would be passed on to the giraffe’s offspring. Darwin would
suggest that neck length was variable and those giraffes with the longest
necks were better able to survive and have offspring. The offspring would
inherit the trait from their parents.

(b) Lamarck would suggest that the continual chasing of prey by the
cheetahs would result in their becoming better and faster runners. This
acquired trait would then be passed on. Darwin would counter that
regardless of the “training,” some cheetahs are inherently faster runners and
would be able to catch more food and have more offspring than the slower
cheetahs. These cheetahs would be more likely to pass the trait of speed to
their offspring.

37. (a) The chance of any particular gene mutating is extremely small;
however, most organisms have extremely large quantities of DNA, and it is
estimated that most gametes carry at least one mutation. Therefore,
mutations are not rare events from the perspective of an individual.
However, as most mutations are neutral and have no obvious effect on the
phenotype of the individual, they go completely unnoticed.

(b) With extremely large numbers of individuals
reproducing over long periods, mutations are extremely
common.

(c) The mutation rate within an elephant population
would be much lower than that within a bacterial
population. Bacteria have a very large population