Transcript Innovation - Projects at Harvard

Stem Arthropods
Anomalocaris
Opabinia
Hurdia
Erwin and Valentine, The Construction of Animal Biodiversity, 2013
Erwin and Valentine, The Construction of Animal Biodiversity, 2013
Genomic Complexity
Monosiga
Amphimedon
Trichoplax
Nematostella
Drosophila
genome
size (Mb)
41.6
167
98
450
180
# genes
9,100
?
11,514
18,000
14,601
# cell types
1
12
4
20
50
# T.F.’s
?
57
35
min. 87
min. 87
# T.F.
families
5
6?
9
10
10
microRNA
0
8
0
40
152
(Erwin, 2009; Erwin & Valentine 2013)
Erwin et al. 2011, Science
Strongylocentrotus
Sea Urchin dGRN
Biotapestry.org
Sea Urchin endomesoderm GRN
Gene Regulatory Network Structure
Erwin and Valentine, Forthcoming, 2012; after Davidson
Davidson & Erwin, 2009
Increase in miRNA
families; complexity
of dGRN interactions
Origin of Developmental
Toolkit
Origin of Eumetazoa
Most signalling
pathways
present
Fedonkin et al The Rise of Animals, 2007
Erwin and Valentine, Forthcoming, 2012
Ecosystem Engineering
Species 2
Species 1
Natural selection
Et
Natural selection
Gene pool
Gene pool
Ecological
Spillover
Genetic inheritance
Ecological inheritance
Ecological
Spillover
Genetic inheritance
Gene pool
Natural selection
Natural selection
Et+1
Gene pool
Cambrian Ecosystem Engineering
• Archaeocyathid reefs (+)
• Sponges & other filter
feeders (+)
• Burrowed sediments (+/-)
• Shelly substrates (+)
• Mesoozooplankton (+)
Ecological Spillovers
• Sponges: sequestering carbon via filtration.
Oxidation of oceans allow increased
production of collagen.
• Burrowing: change in S isotopes, enhances
primary productivity in seds, increases
biodiversity
P & P Definitions
• Innovation “improve on existing ways of doing
things” (which sounds to a biologist like
adaptation)
• Inventions “change the ways things are done”
Invention & Innovation
• Invention is the creation of
something new and distinct
(contrast with variation on
established themes)
• Innovation occurs when inventions
become economically or
ecologically significant
Joseph
Schumpeter
(1883-1950
Increase in miRNA
families; complexity
of dGRN interactions
Origin of Developmental
Toolkit
Origin of Eumetazoa
Most signalling
pathways
present
Defining Novelty
• Are ‘novelty’ and ‘innovation’ synonymous?
• Character based: new construction elements of a
body plan (not homologous to pre-existing
structure)
• Process based: novelty should involve a transition
between adaptive peaks and a breakdown of
ancestral developmental constraints so that new
sorts of variation are generated (Halgrimsson et
a. 2012 J. Exp. Zool)
• Evolutionary novelty
originates when part of
the body acquires
individuality and quasiindependence
• Involves origin of new
character identity
rather than character
state (homology)
How are new evolutionary spaces
created?
• Potentiated by broader environmental setting
(physical, genetic, ecologic)
• Actualized by genetic and developmental
innovations leading to a new clade
• Refined by further developmental and
ecological changes
• Realized as innovations by ecological
expansion and evolutionary success
Mechanisms of Organizational Genesis
•
•
•
•
•
•
•
•
Transposition and refunctionality (var)
Anchoring diversity (ecology)
Incorporation and detachment (var)
Migration and homology (niche const)
Conflict displacement/dual inclusion (ETI)
Purge and mass mobilization (ecology)
Privatization and Business groups (ecol/ETI)
Robust action and multivocality (?)
Nature of Contingency
•
•
•
•
•
Sampling error
Unpredictability of the course of history
Sensitivity to initial conditions (Beatty 2006)
Sensitivity to external disturbance
Macroevolutionary stochasticity
Nature of Contingency
•
•
•
•
•
Sampling error
Unpredictability of the course of history
Sensitivity to initial conditions (Beatty 2006)
Sensitivity to external disturbance
Macroevolutionary stochasticity
And does the ‘topography’ of historical
contingency change over time?
Modern Synthesis
•
•
•
•
Transmission Genetics
Simple path from genotype to phenotype
Primacy of genetic inheritance
Selection within populations as primary driver
of evolution
• Opportunistic
• Uniformitarian
Emerging Perspectives
• No simple mapping from genotype to
phenotype (evo-devo)
• Multiple forms of inheritance
• Multiple levels of selection
• Important roles for mutation and drift in
addition to selection
• Macroevolutionary lags
• Non-uniformitarian
Search Vs Construction
• Innovation is often described as search
through a space of “the adjacent possible”
(Kaufmann, Wagner)
Grassland Evolution
Grass Phylogeny
Kellogg, 2001, Plant Physiology
Macroevolutionary Lags
How are new evolutionary spaces
created?
• Potentiated by broader environmental setting
(physical, genetic, ecologic)
How are new evolutionary spaces
created?
• Potentiated by broader environmental setting
(physical, genetic, ecologic)
• Actualized by genetic and developmental
innovations leading to a new clade