Transcript Evolution Examples

Witness to Evolution
Regents Biology
2006-2007
Witness to Evolution
 Peppered Moth

2 types: dark vs. light
Peppered moth
Regents Biology
Peppered moth: Evolution in action
Year % dark % light
1848
5
95 clean air, light-colored bark
1895
98
2 pollution, dark-colored bark
1995
19
81 Clean Air Act, light-colored bark
industrial melanism
Regents Biology
Peppered moth
 Why did the population change?

early 1800s = pre-industrial England
 low pollution
 lichen on trees = light colored bark

late 1800s = industrial
 factories = soot coated trees
 killed lichen = dark colored bark

mid 1900s = pollution controls
 clean air laws
 return of lichen = light colored
bark
Regents Biology
What data from the
Genome Project can tell us
about evolution of humans
Regents Biology
Chromosome Numbers in
the great apes:
human (Homo)
chimpanzee (Pan)
gorilla (Gorilla)
orangutan (Pogo)
46
48
48
48
Change in chromosome number?
If these organisms share a common
ancestor, then is there evidence in
the genome for this change in
chromosome number
Regents Biology
Ancestral
Chromosomes
Chromosome Numbers in
the great apes
(Hominidae):
human (Homo)
chimpanzee (Pan)
gorilla (Gorilla)
orangutan (Pogo)
46
48
48
48
Fusion
Homo sapiens
Inactivated
centromere
Telomere
sequences
Centromere
Telomere
Testable prediction:
If common ancestor had 48 chromosomes (24 pairs) then
humans carry a fused chromosome; or
If common ancestor had 46 chromosomes (23 pairs) then
apes carry
Regents
Biologya split chromosome.
Human Chromosome #2 shows the exact
point at which this fusion took place
Homo sapiens
Inactivated
centromere
Telomere
sequences
Chr 2
“Chromosome 2 is unique to the human lineage of
evolution, having emerged as a result of head-tohead 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 (2005) “Generation and Annotation of the DNA
sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731.
Regents Biology
In case you had any doubts…
Regents Biology
Evolution is "so overwhelmingly
established that it has become
irrational to call it a theory."
-- Ernst Mayr
What Evolution Is
2001
Professor Emeritus, Evolutionary Biology
Harvard University
(1904-2005)
Regents Biology
2006-2007
Survival of the Fittest
Regents Biology