Sympatric Speciation Simulator

Sympatric Speciation
in evolving
Birds

This program simulates adaptive radiation in a population of birds, loosely based on the Hawaiian honeycreepers. Each bird has a beak described by three traits — length, width and curve. A bird’s beak shape decides which of seven food types it can eat; birds that can’t gather enough food starve, and survivors breed beaks that average their parents’ (with the occasional mutation).

Over many years the population radiates to fill the available food niches. Under semi-random mating it can even split into reproductively isolated clusters — sympatric speciation.

Run the Simulator

Start from two founder birds and watch evolution unfold, or load one of the original saved runs from 1999.

Science fair project & model by Andrew Cantino (1999). Port of the RealBASIC source by Claude.

Main

Speed

Status: Ready

Current Birds:

2

Total Years:

0

Total food left:

Insects:

0

Fruits:

0

S. Seeds:

0

M. Seeds:

0

L. Seeds:

0

C. Corollas:

0

S. Corollas:

0

Graphic Output

Width (x) vs Length (y)

Width (x) vs Curve (y)

Curve (x) vs Length (y)

Highlight birds that can eat…

Matching birds are drawn blue, the rest red. With nothing checked, every bird is red.

Options

Food Support Values

Name

Supports:

Fruit Insects Straight Corollas Curved Corollas Small Seeds Medium Seeds Large Seeds

General Settings

Max Birds Life Span Mutation Rate Req Food Max Offspring Min Offspring

This program allows for 7 food types. These food types are listed on the remaining portion of this window. To determine which beak shapes can eat which foods, you need to set the beak shape requirements. Each food has a beak width, length, and curve setting. If a setting should be null, and is not needed, put 100 in the field.

Example:
Food: Insects Width: < 3 Length: 100 Curve: < 4

Name

Width

Length

Curve

Insects: Fruits: Small Seeds: Medium Seeds: Large Seeds: Straight Corollas: Curved Corollas:

These show the seven beak-shape rules built into the engine, verbatim from the 1999 source (e.g. a bird eats insects if its beak width is <= 3; 100 means that trait is not used). They’re read-only because the rules are fixed in code, exactly as the original was.

Random Mating

Birds mate with a random partner, regardless of beak shape.

Assortative Mating

Each bird selects a partner that is most like itself.

Semi-random Mating

Each bird selects a random partner. If the difference between its beak shape and its partner's is greater than the difference variable (which can be set below) allows, then a new partner will be picked. If a bird can't find any unpaired partner, then it will not mate that year.

Maximum Difference

(The maximum total difference between the two bird's beak shapes.)

The following options control speciation detection and actions taken if speciation is detected.

Detect Species

The program should attempt to detect when speciation has occurred by analizing scatter plot data and looking for species divergence.

When speciation is detected, the program should:

Stop Running
Save a bird array file, and start a new run.
Save a bird array file, and continue the current run.

Even if speciation is not detected, the program should do the above after generations.

Speciation Check

No speciation