1. • Darwin’s Idea of Common Descent
• Darwin’s Idea of Gradualism
• Darwin’s Idea of Multiplication of
Species
• Darwin’s Idea of Natural Selection
2. Darwin’s Idea of
COMMON DESCENT
• evolution = descent with modification
• All organisms are related through descent from some unknown
ancestor that lived in the distant past.
• As the descendants spilled into various habitats over time, they
accumulated diverse modifications (adaptations) that fit them to
specific ways of life.
• The history of life is like a tree.
• The Linnean classification scheme reflected the branching
genealogy of the tree of life, with organisms at the different
levels related through descent from common ancestors.
5. Darwin’s Idea of
GRADUALISM
• The origin of new species and adaptation are closely related
processes.
• A new species would arise from an ancestral form by the
gradual accumulation of adaptations to a different
environment.
• e.g. Darwin’s finches ADAPTIVE RADIATION
large ground finch
small tree finch
woodpecker finch
6. Darwin’s Idea of
MULTIPLICATION of SPECIES
The existence of an enormous number of species
some species are very similar (not as distinct from
each other!)
gradual changes in various characteristics as
organisms became modified according to the
conditions in which they lived
7. Darwin’s Idea of NATURAL SELECTION
as the Mechanism for Evolution
•
Overproduction
- All species have a tendency and the potential to
increase at a geometric rate.
2. Competition
- The conditions supporting life are limited.
- Only a fraction of the offspring in a population will live
to produce offspring, so that the number of individuals
in a population remains fairly constant.
The environments of most organisms have been
in constant change throughout geologic time.
8. 3. Variation
- Individuals in a population vary greatly in their
characteristics.
4. Adaptation
- Some variations enable individuals to produce more
offspring than other individuals.
5. Natural Selection
- Individuals having favorable traits will produce more
offspring, and those with unfavorable traits will produce
fewer offspring.
•
Speciation
- Given time, natural selection leads to the accumulation of
changes that differentiate groups from one another, such
that a new species may arise.
10. Natural Selection Survival of the Fittest
Other examples:
1. Insecticide resistance
2. Drug resistance in bacteria
A population is the smallest unit that can
evolve.
Natural selection acts on individuals, but
individuals do not evolve.
Natural vs. Artificial Selection
Camouflage as an example of
evolutionary adaptation
13.
Divergent evolution – from one species
to several different forms; adaptive
radiation
Convergent evolution – results in
increased resemblance between
unrelated species
Coevolution – occurs when two or
more species evolve in response to each
other
14.
Biological diversity is the
product of evolution.
The mechanism of modification
has been natural selection
working continuously over
long periods of time.
15. At the time, Darwin did not understand the genetic basis for
evolution.
Variations arise from mutation and genetic recombination.
Much of the variation observed in the individuals of a
population is heritable.
16.
Variation mostly occurs as a result of gene mutations
and genetic recombination.
Evolution is the change in allele frequency within a
population over time.
gene
allele
frequency
gene pool
Ernst Mayr
19.
Evolution involves populations, not
Individuals
Species is a population of organisms whose
members can interbreed under natural
circumstances and reproduce fertile (viable)
offspring
20.
Two fundamental processes give rise to new species:
Cladogenesis: The splitting off of one species into two
clades, usually because of geographical isolation, but
also because of reproductive isolation.
Two kinds of species develop by cladogenesis:
Sympatric Species: Those whose speciation is the
product of geographical isolation
Allopatric Species: Those whose speciation is the
product of reproductive isolation of population in the
same region.
Anagenesis: The replacement of an ancestral species by
a daughter species over time; the ancestral species
become extinct.
21.
Cladogenesis:
Time I: Genes flow freely in
region
Time II: Barrier separates two
populations
Time III: Mutations change
genotype and phenotype of 2
populations
Time IV: Two populations cannot
interbreed even with removal of
barrier
Definition: Branching of one
species into two
From clade (“branch”) or group
with common evolutionary
ancestry.
22.
Allopatric speciation
occurs when two
populations are separated
by a geographical barrier
(river, mountain range)
In this example, three
species of fish have
evolved in separate zones
23.
Sympatric species are those
that are separated by a
reproductively isolation
mechanism
Speciation occurs among three
populations of fish even
though the different species
occupy the same region
There are several ways for
subspecies to become
reproductively isolated
24.
Ecological Isolation: Different populations are separated by
occupy a slightly different niche
Seasonal Isolation: The breeding season of two closely related
populations do not match.
Sexual Isolation: One or both sexes of a species initiate mating
behavior that does not act a stimulus to the opposite sex of a
closely related population
Mechanical isolation: Populations do not mate because of an
incompatibility of the male and female sex organs of the
individuals (extreme example: wolves and Chihuahuas)
Gamete Isolation: Incompatibility of sex cell with bodily
environment
Hybrid Infertility or Sterility: Hybrids do not survive or
reproduce (mules)
25.
Micromutation: Mutations with
extensive or important phenotypic
results
Example: Axolotl (species of
salamander)
This salamander starts life as
tadpole-like larvae, as do other
salamanders
Axolotl, however, never grows up
—doesn’t sprout mature legs,
keeps its gills, remains aquatic
existence.
Injection of a hormone enables
maturity and to live on land, so
that one mutation can and does
create major change
26.
Definition: Evolution and spreading out of
related species into new niches
Niche: An environment in which an organism
is found and its adaptive response to that
environment
Generalized Adaptive Radiation: The
adaptation of a species to a wide range of
niches. Homo sapiens is an example.
Specialized Adaptive Radiation: The
adaptation of a species to a narrow range of
niches.
27.
Absence of similar and therefore competing
species
Occurrence of extensive extinction, thereby
emptying an environment of competitors
Adaptive generalization of new group of
related species which enable it to occupy
several niches and displace species already
there.
28.
Example: Darwin’s finches on Galápagos
Islands who were blown there by winds from
mainland Ecuador
Niches opened up for 13 varieties with
different bills, including those that feed on
cactus or eat specific insects in trees
Others use twig or cactus spine to probe for
insects
A vampire finch sucks blood from larger birds
29.
Ground finches (Geospiza) who are seed and cactus eaters;
Tree finches (Camarhynchus), who are insect and bud eaters
Warbler finches (Certhidea) who vary by color.
30.
Definition: Adaptation of a species to a narrow range
of environmental niches
Example: Again, some species of Darwin’s finches on
Galápagos Islands are examples.
Medium ground finch was nearly wiped out in the
1977 drought
Sudden change could eliminate this or others of these
genera and species of finches
Example: prosimians adapt on in habitats afforded by
Madagascar and are close to extinction.
31.
Definition: Adaptation of a species to a wide range of
environmental niches
Examples:
Mammals spread after the disappearance of dinosaurs
65 m.y.a. and occupied innumerable niches, from
grassland (ungulates) to trees (bats)
Monkeys with a mixed diet occupied diverse arboreal
(tree) habitats; they displaced the prosimians
Humans: from frozen north to tropical rainforest or
desert—thanks to culture—are the most generalized
primate
32.
Definition:
Slow, step-by-step changes over time
Intermediate forms assume “missing links”
Darwin postulated this model
Examples: From monkeys to apes; apes to
hominins (e.g. Lucy); and from early hominins
to modern Homo sapiens
33.
Fossil record does not reveal fine gradations from one
lifeform to a descendant life form: no “missing links.”
Bipedalism occurred quickly as the fragmentary fossil
record shows.
Reproductive advantage: do slight changes bestow this
advantage?
Continuum question: at which point does a population
become two species?
Sometimes, change can take place rapidly, either through
oscillating selection or punctuated equilibrium
34.
Definition: Adaptive variation around a norm rather
than direction in response to environmental variation
Example: Medium and small ground finch lacked a bill
strong enough to crack tough seeds
Occurrence of drought selected plants whose seeds had
a tough exterior
Survival of large, longer-billed finches
Smaller, shorter-billed finches returned after the
climate returned to normal,
Shifting bill size and lengths reflected the oscillation of
the environmental conditions.
35.
Definition: Species tend to
remain stable over time, then,
evolutionary changes occur
suddenly (in terms of centuries or
millennia)
Causation: Populations may
become fragmented and isolated,
and from there new forms arise
Small, new populations may
invade a region, and through the
founder effect and better
adaptation, create and spread a
new species
Example: Archaeopteryx (ancient
bird), a dinosaur with feathers:
suddenly appears and may have
created a new class known as
Aves (birds)
37.
Pseudoscience consists of scientifically testable
ideas in form that are taken on faith even after
they are proven as false
(Scientific) Creationism is the belief in a literal
biblical interpretation of the creation of earth in
six days 6,000 to 10,000 years ago
The claim is testable, has been tested, and has
been demonstrated to be false.
38.
Existence of strata, such as the Grand Canyon,
accumulated over 2 billion years falsifies the claim that
the earth is only a few thousand years old
Presence of extinct lifeforms, from fossil fish to
dinosaurs, demonstrate that other forms existed at one
time but are now extinct
Presence of ancient hominins establish extinct
humanlike creatures that look like us but are not us.
Both kinds of evidence are abundant
39.
Species is unit of evolution
Evolutionary change is more random than
progressive
Speciation is the basic process of evolutionary
change
Changes may be gradual or rapid
Scientific rule: follow the evidence
Evidence for evolution is overwhelming in the
form of geological strata and fossil lifeforms
41.
A history of apemen – the track record
Two case studies
1. Neandertals
2. Australopithecines and Lucy
How evolution hinders critical
thinking
How things change
42. The Bible teaches that Evolution begins with
the assumption that
God created man
man has evolved from
ape-like creatures
So God created man in his own image, in the
image of God created he him; male and
female
Genesis 1:27
Pick your relative
43. Holt, Rinehart, & Winston, Biology – Visualizing
Life, 1998, p. 213.
“Look closely at your hand. You have five flexible
fingers. Animals with five flexible fingers are called
primates. Monkeys, apes, and humans are examples
of primates….Primates most likely evolved from
small, insect-eating rodentlike mammals that lived
about 60 million years ago.”
44. Miller and Levine, Biology, 2000, p. 757.
“But all researchers agree on certain basic facts.
We know, for example, that humans evolved from
ancestors we share with other living primates such
as chimpanzees and apes.”
46. New York Times ran an article:
“Darwin Theory Proved True.”
Featured in textbooks and encyclopedias
In 1953 scientists studied the bones
The Truth
A fraud (600 year old bones)
47.
1922 fossil evidence was discovered
Used to support evolution in the 1925
Scopes trial
The claim: 1 million year old
intermediate link
The Truth
An extinct pig’s tooth
49. Time Magazine (Nov. 7, 1977)
“Ramapithicus is ideally structured to
be an ancestor of hominids. If he isn't,
we don't have anything else that is.”
50. The claim: 14 million year old intermediate between ape-like creatures and
humans
The truth
In 1970 a baboon living in Ethiopia was
discovered.
Same dental structure
Similar morphological features found on
Ramapithecus
Ramapithecus dropped from human line
51.
Piltdown Man ……… Hoax
Nebraska Man …….. Pig
Ramapithecus ……..
Ape
What about the dates?
In each case the date (age)
was completely WRONG!
54.
First found near Dusseldorf, Germany in 1856
Constructed to look ape-like
Brain capacity about 200 cc larger
Initial construction discovered to be wrong
Used jewelry
Used musical instruments
Did cave paintings
Capable of speech
Buried their dead
55. Marvin Lubenow, “Recovery of Neanderthal mtDNA:
An Evaluation,” Creation Ex Nihilo Technical Journal,
1998 p.89.
“Most anthropologists recognize burial as a very
human, and a very religious, act. But the strongest
evidence that Neandertals were fully human and
of our species is that at four sites Neandertals and
modern humans were buried together.”
56. From Buried Alive by Dr. Jack Cuozzo
Drawing of a Neandertal fossil
purchased at the souvenir counter at
the museum in Berlin giving an apelike appearance
Lower jaw 30 mm (over an inch) out of the
socket
57. From Buried Alive by Dr. Jack Cuozzo
Flat, human
appearance
Lower jaw 30 mm (over an inch) out of the
socket
59.
Common dates for Neandertals are
130,000 to 30,000 years ago
Neandertals existed for about
100,000 years (2,500 generations)
60. 2000
1
6 billion
300 million
100 generations
Where are the fossils?
There should have been over 50 billion
Neandertals that lived during this time!
61.
1964: Neanderthals are a sub-species of
humans
1997: Neanderthals are a separate species
(based on mtDNA find)
Luigi Cavalli-Sforza (Professor of genetics Stanford
University), Genes, People, and Languages, 2000, p. 35.
“The results of mitochondrial DNA show clearly that Neandertal was not our
direct ancestor, unlike earlier hypotheses made by some
paleoanthropologists.”
62. How was this comparison made?
1,669 modern humans were compared
with one Neanderthal
63.
When compared to modern humans there were 22 mtDNA substitution
differences
Between modern humans the range is from 1 to
24 mtDNA differences
Neanderthal and human
Human and human
What does this mean?
64.
There are a few modern humans who differ by
2 substitutions more than the Neanderthal
individual
Therefore,
using evolutionists logic, these
people are a separate species (not human)
~ 8% of the people here tonight
are not human
65.
Protruding brow ridge
Stocky body build and short extremities
Isolated population of people
Lived in a cold, harsh climate
100% human
Neandertal man,
reconstructed from a
skull found in La
Chapelle-aux-Saints,
France
66. A Case Study in Deception
Lucy and the
Australopithecines
69. John Gurche, artist, National Geographic, March,
1996 p. 109.
“I wanted to get a human soul into this
ape-like face, to indicate something
about where he was headed.”
70.
Lucy discovered in 1974
About 40% of the fossil was found
Claimed to be 3.5 million years old
Claimed bipedal (walked upright)
71.
No similarity in appearance to humans
Long arms are identical to chimpanzees
Jaws are similar to chimpanzees
Upper leg bone is similar to chimpanzees
Lucy’s legs were very ape-like
Brain size (400-500 cc) overlaps chimpanzees
Large back muscles for tree dwelling
Hands similar to pygmy chimpanzee
Feet were long and curved
72. To determine if Lucy walked upright three areas of anatomy were examined
1. The rib cage
2. The pelvis
3. Leg and foot bones
73.
Ape ribs are conical shaped
Human ribs are barrel-like
Human
Circular barrel-like
Ape
Conical shape
74. Peter Schmid (paleontologist at the Anthropological Institute
in Zurich) Quoted from Origins reconsidered: In Search of
What Makes Us Human by Richard Leakey and Roger Lewin
“I noticed that the ribs were more round in crosssection, more like what you see in apes. Human ribs
are flatter in cross-section.
But the shape of the rib cage itself was the biggest
surprise of all. The human rib cage is barrel shaped,
and I just couldn’t get Lucy’s ribs to fit this kind of
shape.”
75. Brad Harrub (Ph.D. Anatomy and Neurobiology)
and Bert Thompson (Ph.D. Microbiology), The
Truth About Human Origins, 2003, p. 47.
“In Lucy’s case, her ribs are conical,
like those found in apes.”
77. J. Stern & R. Sussman, American Journal of
Physical Anthropology, 1983, pp. 291 & 292.
“The fact that the anterior portion of the iliac blade
faces laterally in humans but not in chimpanzees is
obvious. The marked resemblance of AL 288-1
(Lucy) to the chimpanzee is equally obvious…
It suggests to us that the mechanism of lateral
pelvic balance during bipedalism was closer to
that in apes than in humans.”
78. Lucy’s pelvis is “wrong”
because it is very ape-like
PBS Nova Series; In Search of Human Origins
episode one 1994 (Dr. Owen Lovejoy)
79. PBS Nova Series; In Search of Human Origins
episode one 1994 (Dr. Owen Lovejoy)
Parts found between 1908 and 1912 in Piltdown, England
Portion of human skull
Portion of lower ape-like jaw
The claim: 500,000 year old intermediate link
Pithecos = Greek for ape
Discovered in 1930s: jaw fragments and teeth
If you differ by more than 22 substitutions you fall outside the human range according to evolutionists
The single Neanderthal (mtDNA) was extracted from a small isolated group of Neanderthals
Possible explanations
Neanderthals did contribute to the modern gene pool, but their sequences disappeared through genetic loss or selection
The single Neanderthal (mtDNA) was fully human but at the extreme end
The single Neanderthal (mtDNA) was fully human but at the extreme end
Picture of Lucy from: Biology: Understanding Life Third Edition, 2000
C. Owen Lovejoy is Chairman of Anthropology at Kent State University