… one by one, we go in the dark and come out saying how we experience the animal one of us happens...
TRANSCRIPT
![Page 1: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/1.jpg)
The Elephant in the Dark:Resolving evolutionary patterns across timescales
![Page 2: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/2.jpg)
…One by one, we go in the dark and come out
Saying how we experience the animal
One of us happens to touch the trunk.“A water-pipe kind of creature.”
Another, the ear. “A very strong, always movingBack and forth, fan-animal.”
Another, the leg. “I find it still, Like a column on a temple.”
Another touches the curved back. “ A leathery throne”
Another, the cleverest, feels the tusk. “A rounded sword made of porcelain.”
He’s proud of his description.
Each of us touches one placeAnd understands the whole in that way.
The palm and fingers feeling in the dark areHow the senses explore the reality of the elephant
If each of us held a candle there,And if we went in together,
We could see it.
-The Elephant in the DarkRumi (Translated by Coleman Barks)
![Page 3: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/3.jpg)
Another, touches extant populations,…
“A very strong, always moving back and forth [process]”
![Page 4: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/4.jpg)
Another, the fossil record, …
“I find it still, like a column on a temple [with occasional punctuations]”
![Page 5: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/5.jpg)
Another, the phylogeny…
…Brownian Motion might be a good approximation.
![Page 6: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/6.jpg)
How can the evolutionary pattern be all these things?
Contemporary field studies
• Rapid evolution
• High genetic variation
• Strong selection
Fossil record
• Stasis over millions of years
• Geographic variation
• Extinction and species turnover
Comparative methods
• Variance increases through time
• High morphological diversity
• Brownian motion fits reasonably
![Page 7: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/7.jpg)
How can we see the pattern across scales of time?
All studies of phenotypic evolution measure comparable
quantitiesAllochronic
We measure two quantitaties:(1) “time for evolution”
(2) Δ mean
Pop Bmean(z)
Pop Amean(z)
Time interval
Pop X
Synchronic
Pop Bmean(z)
Pop Amean(z) Time interval
![Page 8: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/8.jpg)
Estes and Arnold 2007
Field StudiesFossil Record
Historic
Divergence isn’t dependent on time?
![Page 9: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/9.jpg)
Why is there no time-span effect?
• How can this be consistent with strong phylogenetic signal for body size traits?
Thomas F HansenUniversity of Oslo
![Page 10: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/10.jpg)
Body size is known to have a strong phylogenetic signal
Smith et al. 2004. Phylogenetic heritability of body size between sister species of mammals
(think of the plot like a sib-sib regression)
![Page 11: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/11.jpg)
Estes and Arnold 2007
Field StudiesFossil Record
Historic
Divergence isn’t dependent on time?
![Page 12: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/12.jpg)
Estes & Arnold (2007)
• Neutral drift in trait or adaptive optimum
• Stabilizing selection
• Displaced optimum
• Moving optimum
• White noise motion of the optimum
• Peak shift
![Page 13: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/13.jpg)
Estes and Arnold 2007
![Page 14: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/14.jpg)
Time (Raw timescale)
![Page 15: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/15.jpg)
Example: Brownian Motion process
Time (Raw timescale)
![Page 16: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/16.jpg)
Example: Brownian Motion process
Time (Raw timescale)
![Page 17: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/17.jpg)
Example: Brownian Motion process
Time (Log timescale)
![Page 18: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/18.jpg)
Let’s combine with comparative data:• Log-scaled linear body size traits
• e.g. ln(height) or ln( mass1/3)
• Taxa- Many, but mostly vertebrates
• Field and historic data (e.g. Hendry et al. 2008)
• Fossil record (e.g. Gingerich 2001)
• Comparative data:• Time-calibrated phylogenies &
body size databases• Mammals, Birds & Squamates
![Page 19: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/19.jpg)
Microevolutionary data
![Page 20: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/20.jpg)
Fossil data
![Page 21: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/21.jpg)
Comparative dataMammals
![Page 22: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/22.jpg)
Comparative dataBirds
![Page 23: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/23.jpg)
Comparative dataSquamates
![Page 24: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/24.jpg)
Comparative dataMammalian, Avian and Squamate body size
![Page 25: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/25.jpg)
![Page 26: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/26.jpg)
Comparative dataMammalian, Avian and Squamate body size
“The Evolutionary Blunderbuss” ™ Stevan J Arnold
![Page 27: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/27.jpg)
![Page 28: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/28.jpg)
![Page 29: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/29.jpg)
Study bias?
![Page 30: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/30.jpg)
![Page 31: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/31.jpg)
Models must explain:
“The Stasis Distribution”and
Longer term trends of accumulating variance
![Page 32: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/32.jpg)
Two-layer process
![Page 33: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/33.jpg)
Stochastic modelsBounded Evolution (BE)Brownian Motion (BM)Single-burst (SB) – Exponential time to displacementMultiple-burst (MB) – Poisson Point Process
![Page 34: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/34.jpg)
All datasets- Microevolutionary, Fossil and Phylogenetic:
Model Parameter estimates AIC
White Noise -2940.53
Brownian motion -7877.97
Displaced optimum 1/ =107.4438 -9018.03
Poisson process 1/ =107.3976 -9142.54
Poisson process model fit to subsets of the data:
Dataset Parameter estimates
Microevolutionary & Fossil 1/ =106.1642
Phylogenetic 1/ =107.3375
![Page 35: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/35.jpg)
Multiple-Burst Model• Punctuational change• Stasis distribution:
± 10% linear size change (1 SD)(ME + phenotypic plasticity +
evolutionary change + genetic drift)• Burst distribution:
± 30% linear size change (1 SD) Average time to displacement =
25 my
![Page 36: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/36.jpg)
Multiple-Burst Model:bootstrapped over studies
![Page 37: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/37.jpg)
Parameter estimates and AIC scores for three model fits to the data. Models tested include a bounded evolution model (BE), a Brownian motion model (BM), a single-burst model (SB) and a multiple-burst model (MB). In all models, standard deviations are in units of the natural log size difference. The inverse of the rate parameters (1/ ) for the exponential distribution and Poisson distribution in the single-burst and multiple-burst models, respectively, can be interpreted as the average number of years until a displacement. Details of each model may be found in the SI text.
Dataset Model Parameter estimates
AIC
Microevolution & Fossil BE = 0.1417 -5740.28
BM = 0.0974 1.60e-4 -8298.53
SB = 0.0885 0.396 1/ =106.2990 -8687.00
MB = 0.0874 0.249 1/ =106.1642 -8793.06
Phylogenetic only BE = 0.2986 1106.31
BM = 0.1000 4.61e-5 0.66
SB = 0.1182 0.4451 1/ =107.7344 -171.30
MB = 0.0857 0.2166 1/ =107.3375 -363.26
All data less than 500,000 years
BE = 0.0976 -8493.74
BM = 0.0976 1.94e-7 -8491.74
SB = 0.0260 0.106 1/ =102.276 -8960.72
MB = 0.0872 0.327 1/ =106.337 -8758.38
All data greater than 500,000 years
BE = 0.2997 1417.48
BM = 0.1946 3.99e-5 599.30
SB = 0.1558 0.508 1/ =107.8724 105.76
MB = 0.1480 1/ =107.7482 45.82
![Page 38: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/38.jpg)
Why millions of years?
What process accounts for this pattern?
![Page 39: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/39.jpg)
What pattern makes evolution look like Brownian motion over macroevolutionary time?
• Genetic drift (Lande 1976)?– No, parameters do not work
• Drift of a local adaptive peak? – No, or we could never measure selection
• A statistical pattern in need of an interpretation
![Page 40: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/40.jpg)
What then, is randomly walking?
• “Niches”• Not a real answer• We need more focus on
interpretation and causation!
![Page 41: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/41.jpg)
Is there anything significant about 1-5 milllion years?
• Species life-spans for mammals are ~1-5 million years (Alroy et al. 2000; Liow et al. 2008)
• Marine inverts 2.5-10 my (Foote, 2007)
• Taxon cycles are suggested to occur on the order of 0.1-10 my(Ricklefs & Bermingham 2002)
![Page 42: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/42.jpg)
Liow et al. 2008
![Page 43: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/43.jpg)
Liow et al. 2008
![Page 44: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/44.jpg)
Foote 2007
![Page 45: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/45.jpg)
![Page 46: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/46.jpg)
What role could demography & extinction play?
• Similar to models proposed by Eldredge et al. (2005)
• As fitness-related mean trait value deviates from θ, mean population fitness declines according to a Gaussian function.
![Page 47: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/47.jpg)
• Let the population grow at a multiplicative growth rate, Rt, such that:
and, otherwise .
Population growth (Burger & Lynch 1995)
tt WBR
KN t KN t when where B is the maximum population growth rate and K is the carrying capacity.
1 ttt NRN
![Page 48: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/48.jpg)
G/(ω2 +1)=0.01 σ2ө = 2.25 B=1.025
λ = 1/250 N0 = 10000
Constant population size:
Divergence increases with time
Addition of demography:
Divergence decreases with time
G/(ω2 +1)=0.01 σ2ө = 2.25 λ = 1/250,
Linear increase in average divergence expected
![Page 49: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/49.jpg)
![Page 50: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/50.jpg)
![Page 51: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/51.jpg)
![Page 52: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/52.jpg)
![Page 53: … One by one, we go in the dark and come out Saying how we experience the animal One of us happens to touch the trunk. “A water-pipe kind of creature.”](https://reader036.vdocuments.mx/reader036/viewer/2022070411/56649c7e5503460f94933a4c/html5/thumbnails/53.jpg)
From adaptive landscapes & G-matrices to phylogenetic stochastic models
• Need to account for the scaling from populations species
• e.g. Futuyma’s ephemeral divergence model• Demography, and the dynamics of species
ranges over time (including speciation) can be factored in to explain shifts in species means
• The ultimate “cause” of evolutionary change is change in adaptive landscapes