I.
Biogeography
A. Comparative Anatomy
1. “homologous” structures, similar
2. Fossil record – similar structures, carbon dating
– evolution
II. Theories of Evolution
A. Catastrophism – large environmental disaster 
things change
B. Lamarck’s
1. Inheritance of acquired – characteristics
(organism changed in it’s lifetime – could pass
those changes to offspring)
C. Wallace – “survival of the fittest” evolution
D. Darwin – father of evolution 1858
1. Biological diversity – gene pool – there is always
diversity within a species
2. Fitness – traits best suited for survival
3. Natural selection – survival of the fittest, best
traits will be passed on
4. Artificial selection – man selected, domestication
5. Adaptation – allows for survival
a) Structural – anatomy
b) Behavioral – courtship, hibernation
c) Physiological – how the body works
III. Evidence for evolution
A. Radiometric dating – carbon 14 dating,
radioactive substances break down in half lives –
decay
B. Fossils – imprints of structures within rock
C. Comparative morphology and embryology –
development prior to birth
1. Homologous features – similar structures,
similar embryological development,
Ex. bat and bird wings
2. Analogous features – similar functions develop
differently
Ex. bat wings and butterfly wings
3. Vestigial structures: present, no longer needed
D. Experimental evidence –
• peppered moths, 2 variations white and gray
• Trees with birch (lighter bark)
And lichen – more white moths
• 1860’s coal  soot killed lichen  trees
darken more gray moths
• 1900’s less soot  lichen back lighter
bark- more white moths
Change in frequency of alleles – how genetic
information changes, which traits show up more often
II. Five agents in microevolution
A. Mutation – change in genetic code, lethal, neutral,
beneficial
B. Gene flow – beneficial traits will be passed from
generation to generation – one population to
another
C. Genetic drift – chance alteration of genes
I.
1.
2.
3.
Founder effect – species in new environment will
favor certain genes
Bottleneck – cheetah – severe reduction in
population small population limited gene pool,
greater chance for genetic disorders
Inbreeding – homozygous limited gene pool, greater
chance for genetic disorders
D. Nonrandom mating(sexual selection) – given member of a
population is not equally likely to mate with any other
given member “fittest”
E. Natural selection
1. Adaptations – traits best suited for survival are passed
on
2. Fitness – best adaptive traits
3. Galapagos finches – Darwin – 13 finches – common
ancestor, beak size and shape – and Grant’s study –
evolution can quickly occur
1. Three modes
a) Stabilizing selection
– “average” most
common
b) Directional selection
– “change in the
environment” shift
to one extreme or
the other
c) Disruptive selection
– splits population
into 2 groups
I.
Species – interbreeding populations which
produce viable offspring
II. Reproductive isolating mechanisms – keeps species
separate
A. Prezygotic – prevents sperm from fertilizing
egg
1. Mechanical – not physically compatible
2. Behavioral – “behaviors” are different,
courtship song displays
3. Temporal – breed at different times
4. Gamete – egg and sperm cannot fuse
5. Ecological – different habitats
B. Postzygotic
1. Hybrids – offspring may not survive or
be sterile
III. Mechanisms of speciation
A. Allopatric speciation – “of other countries”
1.species separated by geography change over
time Darwin’s finches
a) Colonization – 1 group of finches  13 species
new island, the fittest survive
b) Genetic divergence – over time species change
due to adapting to new environment
c) Reproductive isolation – gene pool is separated
from original gene pool – changes occur over
time
d) Competition – fittest for environment survive to
breed those characteristics to offspring
e) Further speciation – original species  new
species
B. Sympatric speciation – absence of geologic separation,
fruit flies, hawthornes, apples
C. ????Parapatric speciation – next to small population
on the fringe of a habitat can form it’s own breeding
group
IV. Evolutionary change
A. Vestigial structures: present, no longer needed
B. Coevolution –
symbiotic relationships “mimicry”
C. Comparative biochemistry –
chemical makeup, horseshoe crab,
blood chemistry same as spiders
D. Genetics – DNA
V. Extinction: death of the last of a species
A. Habitat destruction
B. Competition
CHAPTER 18
SYSTEMATICS:
SEEKING ORDER
AMIDST DIVERSITY
I. Taxonomy
A. Linnaeus – father of taxonomy, classification
system based on homologous structures
B. Binomial nomenclature
1. 2 term naming system
2. Genus species – identification system
Homo sapiens, Felis tigris, Felis leo
eastern bluebird (Sialia sialis), the western bluebird (Sialia mexicana), and the mountain
bluebird (Sialia currucoides)—remain distinct because they do not interbreed.
C.Domains
1. Archaea- ancient bacteria prokaryotes
2. Bacteria- modern bacteria prokaryotes
3. Eukarya- eukaryotes divided into Animal, Plant,
Protist and Fungi Kingdoms
D. Kingdoms
1. Animal – heterotrophs, multicellular, eukaryote
2. Plant – autotrophs – multicellular, eukaryote
3. Protist – heterotrophs & autotrophs, unicellular,
eukaryote
4. Fungi – heterotrophs, plant like, multi cellular,
eukaryote
5. Monera – bacteria and viruses, prokaryotes
D. Taxonomic system
1. Kingdom
2. Phylum
3. Class
4. Order
5. Family
6. Genus
7. Species
Humans
Animalia
Chordata “notochord”
Mammalia “hair, mammary glands,
give birth to live young
Primate “binocular vision,
opposable thumb”
Hominidae “walk upright”
Homo
“man-like”
sapien
modern day
E. Taxonomic Key – systematic way to identify organisms
using structures
How Many Species Exist?
• Biodiversity is the total number of species in
an ecosystem
Between 7,000 and 10,000 new species are identified
annually, mostly in the tropics
Tropical rain forests are believed to be home to twothirds of the world’s existing species, most of which
have yet to be named
Because tropical rain forests are being destroyed so rapidly,
species may become extinct before we ever knew they existed
The blackfaced lion
tamarin
Researchers
estimate that
no more than
260
individuals
remain in the
wild; captive
breeding may
be the blackfaced lion
tamarin's only
hope for
survival
The (a) tarsier, (b) lemur, and (c) liontail macaque monkey
all have relatively flat faces, with forward-looking eyes
providing binocular vision. All also have color vision and
grasping hands. These features, retained from the earliest
primates, are shared by humans
Primates
• Some of these adaptations were inherited by
humans
– Large, forward-facing eyes with overlapping fields
of view (allowed accurate depth perception)
– Color vision
– Grasping hands
– Enlarged brain (facilitated hand-eye coordination
and complex social interactions)
Oldest Hominid Fossils
• Hominids include humans and extinct
humanlike primates
• The oldest known hominid fossils are between
6 and 7 million years old
Sahelanthropus tchadensis lived more than 6
million years ago
Exhibits human-like and ape-like
characteristics
Oldest Hominid Fossils
• Ardipithecus ramidus and Orrorin tugenensis
lived between 4 million and 6 million years ago
• Knowledge of these earliest hominids is limited
- few specimens have been found
The first well-known hominid line, the australopithecines, arose
about 4 million years ago
The Earliest Hominids
• The earliest australopithecines possessed
knee joints that permitted bipedal (upright,
two-legged) locomotion
– 4 million year old fossilized footprints confirm that
early australopithecines sometimes walked
upright
An upright stance was significant in the evolution of hominids
because it freed their hands from use in walking
The Australopithecines
• Several species of Australopithecus have been
identified from fossils
• Australopithecus anamensis
• Australopithecus afarensis – believed to have
given rise to:
– A. africanus
– A. robustus
– A. boisei
• All australopithecines were extinct by 1.2
million years ago
The Genus Homo
• The genus Homo diverged from the
australopithecine line 2.5 million years ago
The Genus Homo
• Homo habilis appeared 2.5 million years ago
– Bodies and brains were larger than
australopithicenes
– Retained apelike long arms and short legs
Homo ergaster appeared 2 million years ago
Limb proportions were more like those of modern
humans
The Genus Homo
• Homo ergaster is believed by many to be the
common ancestor of:
– H. erectus (first hominid species to leave Africa
approximately 1.8 million years ago)
– H. heidelbergensis
• Some migrated to Europe and gave rise to H.
neanderthalensis
• Those remaining in Africa gave rise to H.
sapiens (modern man)
Advances in Tool Technology
• Hominid evolution is closely tied to the
development of tools
• Homo habilis produced fairly crude chopping
tools that were unchipped on one end to hold
in the hand
Advances in Tool Technology
• Homo ergaster produced finer tools that were
typically sharp all the way around the stone
– Some of these may have been tied to spears
Advances in Tool Technology
• Homo neanderthalensis produced
exceptionally fine tools with extremely sharp
edges made by flaking off tiny bits of stone
The Neanderthals
• Neanderthals lived in Europe from 150,000 to
30,000 years ago
• They were heavily muscled, had brains slightly
larger than modern humans, walked fully erect,
and constructed finely crafted stone tools
Neanderthals were once believed to be a
variety of H. sapiens; however, molecular
evidence indicates that Neanderthals are a
separate species
Modern Humans
• Homo sapiens appeared in Africa about
160,000 years ago
• European and Middle Eastern H. sapiens
appeared about 90,000 years ago and were
known as Cro-Magnons
Cro-Magnons
• Cro-Magnons had domed heads, smooth
brows, and prominent chins
• 30,000-year-old Cro-Magnon artifacts include:
– Bone flutes
– Ivory sculptures
– Evidence of elaborate burial ceremonies
Unlike their predecessors, Cro-Magnons created
remarkable cave paintings that made use of
sophisticated artistic techniques
Cro-Magnons and Neanderthals
• Cro-Magnons coexisted with Neanderthals in
Europe and the Middle East for as many as
50,000 years
• It is not known why the Neanderthals became
extinct
Two hypotheses have been proposed for the evolution of Homo
sapiens
“African replacement” hypothesis
“Multiregional origin” hypothesis
“African Replacement” Hypothesis
• Members of the genus Homo made repeated
long-distance migrations out of Africa
beginning 1.8 million years ago
• H. sapiens emerged from Africa about 150,000
years ago and spread across the Near East,
Europe, and Asia
The dispersing H. sapiens populations replaced all
other hominids
“Multiregional Origin” Hypothesis
• H. erectus emerged from Africa 1.8 million
years ago and spread across the Near East,
Europe, and Asia
• Continued migrations and interbreeding
occurred among widespread H. erectus
populations
• Regional populations of H. erectus evolved
into H. sapiens
Large Brains
• Highly developed brains may have evolved in
response to increasingly complex social
interactions, such as the cooperative hunting
of large game
If the distribution of this group-hunted meat was best accomplished
by individuals with large brains, then natural selection may have
favored such individuals
Characteristics made possible by a large brain
Language
Abstract thought
Advanced culture
The Cultural Evolution of Humans
• The evolutionary success of humans is the
result of cultural evolution and a series of
technological revolutions
– The development of tools
– The agricultural revolution
– The industrial revolution
“We may not be suited for our role as stewards of life’s
continuity on Earth, but here we are.”
Stephen Jay Gould