The Biodiversity Game

Description by Meghan Willison

This game, called The Biodiversity Game (a.k.a. The Bean Game), was created by Dr. Martin Willison, professor of Biology at Dalhousie University. It has been used as a teaching tool in his course Nature Conservation, where it is used to illustrate the fact that a global loss of diversity is often not noticed locally because local diversity can remain stable or even increase while global diversity drops.

The game is played with five teams (continents) and uses dried beans, of which there must be 20 different varieties (species). During play the referee instructs the players to complete the specified actions for each round; first the enterprise portion and then the rule portion. The game ends when one of three situations is reached; one continent has all the species, one continent has no species, or ten rounds have been completed.

It is important that players are not aware of the true object of the game until play in completed, but are only told that the object is to have the largest number of species at the end of the game. The game is intended to mimic the way the real ecological world works; it involves things like predation, reproduction, competition, disease, primary production, pollution, raids, climate change, and genetic swapping.

Dr. Willison writes, There is a discussion of the outcome at the end. The game actually ends when players realize that their beans are disappearing much faster than they are gaining them. When we played it recently, we had lost over half the species when the game finished, but most teams still had as many, or more, species than they began with. This is the crucial message.

This game is somewhat complex and, without modification, would likely only be useful at the grade 11 or 12 level. It could be used in lessons on diversity, extinction, invasive species, symbiosis, and conservation in Biology. The idea that local diversity can remain stable or increase, while global diversity drops, is a difficult one to comprehend. Using this game to teach the concept, however, allows students to actually see how the phenomenon can occur.

The entire game could be played during one class (it takes about an hour to complete), or students could play one round at the beginning or end of each class, stretching the game over a couple of weeks. The first option allows students to see the entire process during a short period of time and then to reflect on the outcome. The second option, however, would allow for discussion or written submission of thoughts and ideas following each round.

Also, the game could be played by the class as a whole (where all of the students are divided into five teams) or in groups of five, in which case each individual represents a continent. The second option would probably be more valuable, as it could allow for several different outcomes to occur and be available for discussion. One group might end the game after ten rounds, while another might finish earlier, when one continent is left with no species.

Some examples of curriculum outcomes (from Biology 11) that could be achieved with the help of this game are:
(1)318-9: Analyze interactions between and within populations,
(2) 118-10: Propose and evaluate courses of action on social issues related to the natural balance of ecosystems, and
(3) 318-1: Describe population growth and explain factors that influence populations growth.


The objective of the game is to have the largest number of species at the end of the game. At the start, there are 2 each of 4 species (for a total of 8 beans*) in each of 5 continents (teams).

The game ends when:

(a) one continent has all 20 initial species

(b) a continent has no species, or

(c) 10 rounds of play have been completed

There are 2 elements to each round of play:

(a) enterprise round

(b) rule round

Teams of players must keep track of rules. If a player notices that a team has broken a rule, the referee will reward the observant team accordingly. Rules are not retroactive they apply from announcement onwards.


Enterprise: Exploration

On a voyage of discovery, each continent collects two specimens from the other continents. The specimens may be of the same species or of different species, and may come from either one or two continents. Teams may not refuse to donate specimens.

Rule: Reproduction

Single specimens reproduce the referee provides an extra one for all singletons. This rule is applied after each enterprise round.


Enterprise: Trade

On a trade mission, each continent sets out with two specimens and exchanges these with other traders (note: there is no haggling the specimens to be traded are selected prior to trading and all traders meet as a group to exchange wares). One group will fail to trade and returns home with their original beans.**

Rule: Limit of primary production ***

The maximum number of individuals that any continent can support is 20. If a continent has more than 20 specimens, the excess must be given to the referee.


Enterprise: Power trip

Each continent possessing a Casa Italia bean visits ONE continent of their choice and selects two specimens of their choice to take home.

Rule: New species discovered

Scientists proclaim that the reddish Black Beauty is actually a different species, and a breeding program is developed. It doubles and doubles again in population size (i.e. there are now 4 of them). Subsequent reproduction of Red Beauty follows the normal rule.


Enterprise: Trade again

On a trade mission, each continent sets out with two specimens and exchanges these with other traders (note: there is no haggling the specimens to be traded are selected prior to trading and all traders meet as a group to exchange wares). One group will fail to trade and returns home with their original beans.

Rule: Predation

Killer whale beans are voracious predators of yellow beans. Yellow Fever beans are adapted to surviving with Killer Whales, but Yellow Tone, Yeller, Rich Yellow and Soy die out completely if Killer Whales are present. Teams must give all predated specimens to the referee. Remember: this rule applies for the remainder of the game!


Enterprise: Raid

Holders of Yellow Fever beans consider themselves to be specially powerful. Each continent holding Yellow Fever raids a continent without Yellow Fever, and removes all specimens of one species, giving these to the referee. In addition, they return home with one specimen of another species. [Note to referee: if one continent is left with no specimens at this point in the game, the referee rewards that continent with one of their original species.]

Rule: Competition

Large beans compete for space and crowd out others. Pygmy beans are immune from this effect, but in all other cases, if 4 or more exotic species are present in a continent, one of the native species becomes locally extinct. This will be the least numerous. All specimens of an extinct species are given to the referee.


Enterprise: Bullying

Red Tone beans become very unfashionable and disadvantageous. Any continent NOT holding Red Tone beans visits each of the continents holding Red Tone beans, and takes one specimen home.

Rule: Hidden Disease

Red Beauty carries a slow virus that has been triggered by some unknown factor. This virus is lethal for predominantly purple beans (Rich Purple, La Phase and Purple Prince). All specimens of these beans must be given to the referee if Red Beauty is present.


Enterprise: Interloper

Invasive species are carried from one continent to another as a result of carelessness. Each continent gives one specimen of a species of their choice to two other continents. (Note to players: its permissible to give away a damaging species).

Rule: Mutualism

Some species are dependent on having others around. If any continent has two or less of its original native species, one of the remaining native species dies out and all specimens of that species are given to the referee. Note: this rule applies for the remainder of the game.


Enterprise: Pollution

In an attempt to keep rare species alive, Freon, a refrigerant gas has been invented. It has damaged Earths ozone layer, and light coloured species are at risk. White Tone dies out completely, and all populations of Yeller are halved in number. There is no trading in this round.

Rule: The rule that single beans reproduce is suspended for the remainder of the game; pollution has reduced the health of all populations.


Enterprise: Optimism

The promoters of the enterprise spirit state that trading can increase biodiversity. All continents trade beans freely for one minute by exchanging beans at will. The referee will announce Start Trading and End Trading!

Rule: Genetic Swamping

Interbreeding occurs between black beans, such that any single black bean that is in the presence of more than one bean of another black species dies out. This rule applies to the following beans: Black Tone, Killer Whale, Dark Cattle, Rich Black and Black Beauty. All Players should check for rule violations at this stage in the game.


Enterprise: Climate Change

Trading was so vigorous in the previous round that large volumes of greenhouse gases were released, and the climate has changed. Beans that have white in them die out as a result of their intolerance of warm climates. In addition, any species that exist as single individuals, die out as a result of the non-viability of a small non-reproducing population.

Rule: Players count the score and discuss the outcome of the game. What is the diversity per continent? What is the global diversity? [Note: if the game ended prior to Round Ten, this rule is played at that time.]


* The game if designed to be played with beans, but other playing pieces (eg. colored blocks), of which there must be 2 each of 20 types, are fine. Wherever bean varieties are mentioned in the rules, simply replace these with descriptions applicable to the playing pieces being used.

** The last team to trade will not be successful. This rule is designed to represent the fact that, in the real world, some trade fails.

*** For explanations of many of the biological/ecological terms found within the rules, please refer to the links below.

30 January 2003

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