WHAT IS EVOLUTION?
Evolution is a change in
gene pool over time.
It also is the idea that new
species develop from earlier
species, sometimes
referred to as “descent with
modification”
FAQ: Isn’t evolution only a
theory?
It is a fact in the respect that
yes, it has indeed occurred
and is occurring on a daily
basis.
It is a theory in the respect
that scientists disagree on the
details of how it occurred.
Remember what a theory
in science is - a well-substantiated
explanation of some aspect of the
natural world that can incorporate
facts, inferences, and tested
hypotheses* (not a hunch or guess)
*(National Science Foundation)
Next Battleground: Dover, PA
Dover trial
began on
Monday:
Sept. 26, 2005
TheScope
Scope andand
Limitations
of Science Are
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The
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Academic Issue
More Than An Academic Issue
What is the evidence of evolution?
1) The Fossil Record
2) A Universal Genetic Code
3) Common Molecular Sequences
4) Transitional Fossils
The Fossil Record and Transitional
Fossils
Evidence - A transitional fossil linking
past and present
The Branched Evolution of Horses
Evidence - Molecular Data and the
Evolutionary Relationships of Vertebrates
Evidence - Homologous Structures:
anatomical signs of descent with
modification
Homologous Embryos
Evidence - Evolution of insecticide
resistance in insect populations
Evidence - The evolution of fruit fly
(Drosophila) species on the Hawaiian
archipelago
•Vestigial Organs/Structures
Including:
•Thirteenth Rib (vs. 12)
•Appendix
•Wisdom teeth
•Male nipples
• Rudimentary ear muscles
• Coccygeal (tail) vertebrae
Vestigial Structures(continued)
•Body Hair
•Palmaris Muscle – for climbing
and is missing in 11% of humans
• Pyramidalis Muscle – more than
20% of humans lack this relic from
marsupials
•Subclavius Muscle – in the
shoulder region; useful for
tetrapods
Vestigial Structures (continued)
•Third Eyelid – a common
ancestor of birds and mammals may
have had a membrane for protecting
the eye
•Plantaris Muscle – for grasping
has disappeared in 9% of humans
•Neck Ribs – appear in 1% of
the population
FAQ: Are you going to
teach us that we are
descendants of apes?
•No, That’s an inaccurate conception of evolutionary theory. We have
the closest common ancestry with
the great apes
A Molecular Test of
Common Ancestry
Chromosome
Numbers in the Great
Apes:
Human (Homo) 46
Chimpanzee (Pan)
48
Gorilla (Gorilla) 48
Orangutan (Pogo)
48
Testable prediction: If these
organisms share a common
ancestor, that ancestor had 48
chromosomes (24 pairs)
Chromosome Numbers
Ancestral
in the great apes
Chromosomes
(Hominidae):
Fusion
Homo sapiens
Human (Homo) 46
Chimpanzee (Pan) 48
Gorilla (Gorilla) 48
Orangutan (Pogo) 48
Inactivated
centromere
Telomere
sequences
Centromere
Telomere
If these organisms share a
common ancestor, that ancestor had 48
chromosomes (24 pairs)
Testable prediction:
Chromosome Numbers
in the great apes
(Hominidae):
Human (Homo) 46
Chimpanzee (Pan) 48
Gorilla (Gorilla) 48
Orangutan (Pogo) 48
Hillier et al (2004) “Generation and Annotation of the DNA sequences of human
chromosomes 2 and 4,” Nature 434: 724 – 731.
“Chromosome
Homo sapiens
Inactivated
centromere
Telomere
sequences
2 is unique to the human
lineage of evolution, having emerged as a
result of head-to-head fusion of two
acrocentric chromosomes that remained
separate in other primates. The precise
fusion site has been located in 2q13–2q14.1
(ref. 2; hg 16:114455823 – 114455838), where
our analysis confirmed the presence of
multiple subtelomeric duplications to
chromosomes 1, 5, 8, 9, 10, 12, 19, 21 and 22
(Fig. 3; Supplementary Fig. 3a, region A).
During the formation of human chromosome
2, one of the two centromeres became
inactivated (2q21, which corresponds to the
centromere from chimp chromosome 13)
and the centromeric structure quickly
deterioriated (42).”
Hillier et al (2004) “Generation and Annotation of the DNA sequences of human
chromosomes 2 and 4,” Nature 434: 724 – 731.
FAQ: If we have a common
ancestor with apes, why are there
still apes?
FAQ: Doesn’t “believing” or
“accepting” evolutionary theory
mean you don’t believe in God?
No, most mainstream religions
accept modern evolutionary
theory it premises
FAQ: Why can’t we learn
creationism and evolution?
Should “equal time” be
devoted to both?
FAQ: Isn’t evolution always
improving organisms?
Not always, but there is a drive
towards a particular phenotype.
Evolution is a result of the interactions
between species and their
current environments. If these
conditions change, an apparent
evolutionary trend may cease
or reverse itself.
FAQ: Why is it that
important anyway?
Evolution is a central unifying
theme incorporating:
- molecular (DNA)biology
-cellular biology
-genetics
-taxonomy
- physiology
Evolution
Is Biology’s Unifying Principle
Evolution Is Biology’s Unifying Principle
“Nothing in biology makes
sense except in the light of
evolution.”
Theodosius Dobzhansky,
1973
How is evolution both a fact and
a theory? What is meant by the
word, “theory”?
What was the last major court
case dealing with teaching
evolution in schools? What was
the ruling?
List two major pieces of evidence
that demonstrate evolution has
occurred.
Place the following events in
chronological order from first to
most recent using “Pacing
Geologic Time”
•evolution of reptiles
•evolution of mammals
•evolution of birds
•evolution of amphibians
•first flowering plants
Know These in Chronological Order:
•evolution of eukaryotes
•first multicellular life
•earliest fish
•first amphibians
•first reptiles
•first dinosaurs
•first mammals
•earliest birds
•first flowering plants
•early primates
•earliest humans
1)Calculate the percentage of
time that humans have been on
the earth.
2) The fossil record supports the
theory that all multicellular
evolved within the past ______
million years.
Classify a snake from
its proper domain down to its
class.
Organisms that start their
lives in water and move onto
land are called ….
Pacing Geologic Time Answers
1)3500 million years ago (3.5 billion)
3) 2800 million (3500 mill – 700 mill)
5) The geologic events are further
apart
6) 3.5 million X 100 = .07%
4600 million
7) amphibians, reptiles, mammals,
birds.