Death: the odds of a specific organism dying come from two factors: the overall odds of death and the size of the organism combined with the way death odds scale with size. This second term can be thought of as size-based toughness. Death frequency establishes the baseline rate at which an organism faces death. When this occurs a size 1 organism always dies. Larger organisms may use their size-based toughness to survive. This scales directly with size. If a size 100 individual is 4 times tougher than a size 1 individual a size 50 individual is 2 times tougher than a size 1. Actual odds of death (combining these terms) are written below the input fields.

Food is the amount of energy an organism receives per turn. This is based on Food amount, the baseline, scaled by Size food advantage. An individual gets the basic food unit times its own size to this power. This can be difficult to intuit, so there is a graph that will show this relationship for you.

Competition: when the population goes over 50 competition begins and becomes more severe as the board fills. Competition has two effects: first, it limits food. At normal competition (100%) this will lower food by 80% with the board full. Competition also causes fights which either wound an organism (increase its chance of death until it heals) or kill it outright. The odds of losing a fight and the damage taken in doing so are both based on the size difference between the combatants. The strength of competition alters both these effects. For instance, at 200% all competition effects are doubled.

Disasters: disasters have a frequency and a strength. The frequency is the odds of a disaster happening, not a counter until one happens. When a disaster occurs it kills a percent of the population between 0 and the value entered for "Disaster kills up to this % of population".
Generally, disasters kill organisms following the toughness rules set in the lines above them. E.g., if size 100 organisms are 20 times less likely to die normally than size 1 organisms they will also be 20 times less likely to die in a disaster. This can be overidden by checking "Disasters kill all sizes equally". In this case all sizes of organism are equally likely to die.
This section includes a pause button, a turn counter, and a notice that appears after 100 individuals have reproduced. This notice will mark what turn this occurred on, which can be used to determine what life histories increase the population faster. The turn counter will also stop if three individuals managed to reproduce but after this the population goes to zero.

The edit mode selectors allow you to switch beween editing the environmental parameters and the species parameters and seeing graphs.
The left side of the screen has 100 spaces that can be occupied by organisms. Organisms will be represented by black silhouettes whose relative size indicates the size of the organism.

The background will be a shade between red and purple. Redder colors indicate that the organism has stored less energy for reproducing, bluer/purple colors indicate that more energy is stored for this purpose.
Most of these labels are self-explanatory.

Died without reproducing is the number of individuals that have died prior to reproducing at all.

DWR percent is Died Without Reproducing percent, effectively the juvenile mortality percent.

Organisms that have reproduced counts the number of individuals living and dead that have had offspring.
Energy per offspring: energy required to make an offspring (max 999). The more energy you put in an offspring the larger it will be, topping out at 50% adult size.

Chart: the chart shows energy usage. At every size an organism allocates energy to growth and/or reproduction. Together these add up to 100% of all energy. The more red at a given size the more energy the organism spend on reproduction and the less on growth.
However, organisms can only store energy equivalent to their body size times 10. A blue line marks at what size an organism could hold enough energy to reproduce. Organisms can begin storing energy before this, but that can be a waste of energy.

Straight lines: this makes the lines on this chart straight, drawn from start to midpoint to end (which is always size 100, 100% of energy used to reproduce). If unchecked the lines are curved (technically quadratic bezier curves) which "rounds" the corners of the chart.

Line between start and finish, no midpoint: this eliminates the midpoint on the chart. Now the line simply runs start to end.

Size at sexual maturity: defines how large an organism is before it begins storing any energy for reproduction. Using this input field directly is the easiest way to prevent an organism from spending any energy on reproduction until a certain size.

Midpoint: Without a midpoint organisms simply spend no energy until sexual maturity and then progress evenly to 100% of energy on reproduction at size 100. A midpoint allows you to make more interesting energy allocations, as the energy graph will connect start, midpoint, end point rather than simply start to end. You can also set a midpoint by clicking on the chart, which will update the numbers in these fields.

100 new parents at turn: __

Death frequency: 1 in

Size 100 organism is this much LESS likely to die than a size 1 organism

Food amount

Size food advantage

Competition strength %

Disasters happen about once per this many turns

Disaster kills up to this % of population

Energy per offspring

You can click on this canvas to set a mid-point for the line. Red represents energy spent on reproduction, white is growth. The blue line represents the size at which the organism can first store enough energy to reproduce given energy required for an offspring.

In stages below energy not spent on reproduction is used for growth
Size at sexual maturity (below this all energy is used for growth).

Midpoint: Size
Spend this % of energy on reproduction:

Died without reproducing
DWR percent
Organisms that have reproduced
Average age at death
Average size at death
Average age of first reproduction
Average number of offspring for
reproducing individuals