Vertebrate Evolution: Testing Adaptation Hypotheses using Biorobotics.

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)