vertebrate evolution: testing adaptation hypotheses using biorobotics
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Vertebrate Evolution:Testing Adaptation Hypotheses using Biorobotics
Using Artificial Life to Study Extinct Life
Study life as it was.
Ideal explanations of adaptation
1. Genetics (type, heritability, interactions).
2. Polarity (ancestral and derived states).
3. Function in the ecological situation.
1. Population structure (demography, gene flow).
2. Selection environment (spatial & temporal patterns).
3. Responses to selection in that environment (outcomes).
Population-level Information
Trait-level Information
Brandon, R. (1990). Adaptation & Environment
Solution? ALife
The Artificial Life Cycle for Biorobotics
Solution? ALife
1. Genetics.2. Polarity3. Function in the
ecological situation.
1. Population structure.2. Selection environment.3. Responses to selection
in that environment
The Artificial Life Cycle for Biorobotics
Question: Why did vertebrae evolve multiple times independently?
Photo by Flickr user hankplank Photo by Flickr user tobze
Radiograph by Marianne Porter
Hypothesis: Vertebrae are an adaptation for enhanced predator avoidance during foraging
+ + =
biomimetic notochord
porcine gelatin crosslinked in 1.0 % glutaraldehyde
insert and caudal finring vertebrae
Delrin™
b
artificial vertebral column
Prey
Predator
1
1
10
10
20
20
30
30
40
4050
50
60
60
70
80
70
80
90
100
90
100
escape
160 160
relative fitness, , rewards —foraging u, average velocity (ms-1) R, average distance from light (m)
predator avoidance D, average distance from predator (m) a, peak escape acceleration (ms-2) , startle responses
For individual i in generation j.Population size = 6.
The individuals with the top three ’s are awarded 6, 4, and 2, gametes, respectively, for the mating pool.
new individuals
diploid parentsn = 6 n = 3
selection
meiosis and mutation
randomized mating
n = 6
offspringgene pool
n = 12
ζ N
b
haploid gametes
n = 6
diploid offspring
N
N
b b ζ ζ
reproductives
N, number of
vertebrae
z, predator detection threshold
(mm)
b, caudal fin span (mm)