Making offspring from one parent only. The offspring get a full copy of that parent's genes, so they are identical to it and to each other.
Budding
The way a hydra reproduces asexually. A new hydra grows from the side of its parent, then breaks away and lives on its own.
Sexual reproduction
Making offspring from two parents. An egg from one joins with sperm from the other, and the offspring gets one chromosome of every pair from each parent.
Offspring
The young that a parent, or a pair of parents, produces.
Clone
An offspring carrying exactly the same genes as its parent. Every bud on the one parent route is a clone.
Chromosome
A long piece of DNA that carries genes. A hydra has 30 of them, in 15 matching pairs, and so does every one of its offspring.
Gene
A section of a chromosome that carries the instructions for one trait, such as body color.
Allele
One of the versions a gene can come in. This sim writes them as letters, so R and r are the two alleles of the cold tolerance gene.
Dominant and recessive
When the two alleles of a pair disagree, the dominant one decides the trait and the recessive one is hidden. Here the capital letter is dominant, so one capital R is enough.
Trait
A feature of a living thing that you can observe, such as body color, tentacle length, or whether it survives cold water.
Variation
The differences between offspring of the same parents. Sexual reproduction produces variation; asexual reproduction does not.
Cold tolerance
The trait this sim follows. A hydra carrying at least one capital R survives cold water; one with two lowercase r alleles does not.
Tab: move through the route buttons, the actions, the parents and the pond.