Glossary
evolution, coevolution, host-parasite interactions, Muller’s ratchet, parthenogenesis, Red Queen hypothesis, sexual reproduction
Short definitions of terms as used in this book. These definitions do not include all possible nuances.
carrying capacity: The population density at which females have just enough food to replace themselves. Sexual females must make two offspring to replace themselves (assuming a one-to-one sex ratio), while asexual females must only produce one offspring. Hence, asexuals should have higher carrying capacities, as shown in Figure 1.2.
clone: A lineage of parthenogenetic females descended from the same asexual female. Members of the same clone may have small genetic differences, which accumulate by mutation over time.
cost of males: The reduction in the per-capita growth rate of sexual populations due to the production of males. The cost of males is the appropriate cost for considering sexual subpopulations in competition with obligately asexual subpopulations.
cost of meiosis: The reduction in relatedness between mother and offspring due to outcrossing. The cost of meiosis is the appropriate cost for considering the spread of alleles that induce self-fertilization.
cross-fertilization: The exchange of gametes between different individuals, which may or may not be related.
outcrossing: A form of cross-fertilization, which specifies crossing between unrelated individuals.
parthenogenesis: Any form of asexual reproduction through ova.
recombination: Genetic exchange between homologous chromosomes during meiosis, especially when the exchange leads to gametes with allele combinations not represented on the parental chromosomes.
self-fertilization: The fusion of gametes from the same individual.
sex/rec: Shorthand for sexual reproduction and recombination.
sexual reproduction: I use the term here to mean cross-fertilization between unrelated individuals. However, the term is more general and can be used to mean the incorporation of novel genetic material by any mechanism.