Transcript Ontogeny and Phylogeny - Developmental Biology

MECHANISM of DARWINIAN NATURAL SELECTION
1. Variation exists in the population
2. Competition for survival, most animals dying
before reproducing
3. Survival of those most fit for the environment
4. Offspring are from the survivors
5. Offspring inherit the genes that made their parents
fit for the environment.
DIVERSITY EXISTS WITHIN POPULATION
Homo sapiens subgraduensis
DEATH IS NOT RANDOM; IT IS SELECTIVE
Changes in finch beak morphology during drought of 1976/1977
THE MODERN SYNTHESIS
“Evolution is a change in the genetic composition of populations.
The study of the mechanisms of evolution falls within the province
of population genetics.”
--Theodosius Dobzhansky. 1951
CHARLES DARWIN
ON THE ORIGIN OF SPECIES
1859
“Community of embryonic
structure reveals community
of descent.”
“Embryology rises greatly in interest, when we look
at the embryo as a picture, more or less obscured,
of the progenitor, either in its class or larval state,
of all the members of the same great class.”
HOMOLOGY
“The same organ in all its
varieties of form”
Serial Homology
Derived forms within
the same organism
Special Homology
Derived forms between
different species
Versus
Sir Richard Owen
Analogy
Forms similar due to
same function
KARL ERNST von BAER:
“The general features of a large group of animals
appear earlier in development than do the specialized
features of a smaller group…The early embryo is never
like a lower animal, but only like its early embryo.”
DARWIN (1874):
“Thus, if we may rely on embryology, ever
the safest guide in classification, it seems
that we have at last gained a clue to the
source whence the Vertebrata were
derived.”
AGGASIZ (1874):
“One could hardly open a
scientific Journal or any
popular essay on Natural
History without meeting
some allusion to the
Ascidians as our
ancestors.”
THEOLOGICALLY TRAINED PASSENGERS
ABOARD HMS BEAGLE
Charles Darwin, 22
Cambridge University, 1830
York Minster, ca. 27
Church Missionary Society, 1830
EVIDENCE of COMMON DESCENT:
1. Material evidence
Biblical Archeology
Herod’s Palace, Israel
Paleontology
Fossil Archeopterix showing feather
imprints and a reptilian body
EVIDENCE for COMMON DESCENT:
2. VESTIGIAL APPARATUS
“Old Testament” Stories
Would the story of Ahab been
independently created in Judaism
and in Christianity?
Unused structures
Would the aortic arch have been
independently created in fish and
In mammals?
CLADOGRAM ( partial) of VERTEBRATES:
DESCENT WITH MODIFICATION
CLADOGRAM (Partial) OF WESTERN RELIGIONS
DESCENT WITH MODIFICATION
TWO CLADOGRAMS of WESTERN RELIGION
BASED on DIFFERENT SYNAPOMORPHIES
Synapomorphies of liturgy
and ritual: Protestantism
splits from Catholicism
Synapomorphy of papal
primacy: Protestantism splits
from Orthodoxy
INDEPENDENT EVIDENCE for COMMON DESCENT:
3. Historical Records
Religious textual documentation
Biological genetic documentation
GENETIC EVIDENCE for DESCENT WTH MODIFICATION
MOLECULAR SYNAPOMORPHIES
Phylogenetic tree made from interspersed DNA elements. Four transposon
insertions, at loci 4-7, define a clade of whales and hippos.
Ernst Haeckel
“ONTOGENY RECAPITULATES
PHYLOGENY””HY
ONTOGENY RECAPITULATES
PHYLOGENY:
1. Correspondence
2. Terminal addition
3. Truncation
ONTOGENY
PHYLOGENY
Evolution is based on Haeckel’s diagrams about as much as Christianity is based on
Titian’s paintings.
HAECKEL’S CRIMES WERE FAR WORSE:
“The lower races…are physiologically nearer the mammals--apes and dogs--than to the
civilized European. We must, therefore, assign a totally different value to their lives.”
“He (Jesus) is generally regarded as being purely Jewish. Yet the characteristics
Which distinguish his high and noble personality and which give distinct impress
to his religion are certainly not Semitical. They are the features of the higher Arian
race.”
--The Riddle of the World, 1899
THE DEMISE of EVOLUTIONARY MORPHOLOGY…
“It is difficult, even if possible, to say whether the differences or the
resemblances have a greater zoological value (because we have no
clearly defined standard of zoological value).”
-A. Sedgwick, 1894.
“Haeckel’s “incautious generalization” has “done more to delay
the progress of sound phylogeny than any other modern
speculation.”
-E. S. Goodrich, 1924
…AND THE EXODUS TO GENETICS
"Morphology having been explored in its minutest corners, we
turned elsewhere...The geneticist is the successor of the
morphologist."
-W. Bateson, 1894
EXORCISING THE GHOST of ERNST HAECKEL from BIOLOGY:
Stephen J. Gould, Ontogeny and Phylogeny, 1977.
1. Confusion of von Baer with
Haeckel. Von Baer established
commonality of embryonic
forms. Haeckel believed that
embryos of later organisms
past through adult stages of
primitive organisms.
2. Darwin used von Baer, not
Haeckel. However, Haeckel
became popular and eclipsed
the Darwinian/von Baer view.
FRANÇOIS JACOB: EVOLUTION AS TINKERING
with REGULATORY GENES in the EMBRYO
“Small changes modifying the distribution in time and space of
the same structures are sufficient to affect deeply the form, the
functioning, and the behavior of the final product--the adult
animal. It is always a matter of using the same elements, of
adjusting them here or there, of arranging various combinations
to produce new objects of increasing complexity. It is always a
matter of tinkering.”
RICHARD B. GOLDSCHMIDT:
Evolution consists of inherited changes of development
Functional biology = anatomy, gene expression
Development = d[Functional biology]/dt
Evolution = d[Development]/dt
PAX6/Eyeless Expression in
Insect and Mouse Eye Primordia
HOMOLOGOUS GENES for ANALOGOUS TRAITS
Mouse Pax 6 instructs fly compound eye formation in antenna
HOMOLOGOUS HOX GENES: DERIVATION
HOMOLOGOUS HOX SEQUENCES:EXPRESSION
MUTATIONS IN
REGULATORY GENES
CAN GIVE THE
PROTEINS NEW
PROPERTIES: UBX
ACQUIRES THE
ABILITY to REPRESS
DISTAL-LESS in the
INSECT CLADE
R. Galant and S. B. Carroll,
2002. Nature 415:910.
Ronschaugen, M. et al.
2002. Nature 415: 914.
.
HOW THE DUCK GOT ITS WEBBED FEET
Merino et al., 1999. Dev. Biol. 200: 35 - 45.
Chick
Hindlimb
Duck
Hindlimb
BMP
Gremlin
Apoptosis
Newborn
HOW THE DUCK GOT ITS WEBBED FEET. II.
Experimental Manipulation of Chick Feet
Untreated
Chick Hindlimb
Chick Hindlimb Treated
with Gremlin-Containing
Bead in Interdigital Space
ORIGIN OF FEATHERS FROM SCALES
Through Repetition of SHH-BMP Interactions
(Harris, M., et al., 2002)
GIS MODELING of TOOTH DEVELOPMENT:
FINE RESOLUTION of MORPHOGENETIC CHANGE
(Jernvall et al., 2000)
GENE EXPRESSION PATTERNS PREDICT
MORPHOLOGICAL CHANGES BETWEEN SPECIES
MATHEMATICAL MODELING of
TOOTH EVOLUTION BY ANALYSIS
of GENE EXPRESSION CHANGES
(A. Salazar-Ciudad and J. Jernvall, 2002)
Developmental Mechanisms for
Phylogeny
Shigeru Kuratani et al. 2001. Phil. Trans.
Roy. Soc. London B 356: 1615-1632
Population Genetics
Variation within
population
Genes in adults
competing for
reproductive
success
Developmental Genetics
Variation between
populations
Genes in embryonic
and larval
organisms
building structures
Survival of the fittest
Arrival of the fittest
Natural selection
Phylogeny
A NEW EVOLUTIONARY SYNTHESIS
EXPLAINING BIODIVERSITY