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GENERATING DIVERSITY IS HARD. "The diversity of complex structures and functions in the living world is striking. The origin of new and complex structures and functions is fundamental for shaping the diversity of life. Such key innovations are rare because they require multiple interacting changes." https://lnkd.in/dgNuuqi View in LinkedIn

DIVERSITY. "Evolutionary interactions between species, and coevolution show that the complexity of genetic evolution goes on increasing, even beyond the species level. One thing is clear; the majority of the diversity of life and life forms is not just due to adaptation to static environments; biotic interactions are probably much more important. The biotic environment is itself constantly evolving, leading to orders of magnitude more diversity possible than could be produced by evolutionary adaptation to simple physical conditions." Lovely overview. https://lnkd.in/dZuwxPf View in LinkedIn

ACCEPTED CONCEPT. "Coevolution has been a controversial concept within evolutionary biology. While at times its role as a major factor shaping the evolution of life has been questioned, today coevolution is viewed as a powerful process generating evolutionary change." https://lnkd.in/d3gZgG7 View in LinkedIn

THE ENTANGLED BANK. "In the Origin of species, Darwin used the word coadaptation to refer to reciprocal evolutionary change. Repeatedly in the Origin of species he emphasized the importance of interactions between species and closes the book with the concept of the entangled bank where he marvels at the exquisite adaptations of species to one another." https://lnkd.in/d3gZgG7 View in LinkedIn

COEVOLUTION VARIABLES: "whether the genome is haploid or diploid; the number of alleles involved and whether there is pleiotropy (especially fitness costs independent of the host–pathogen interaction); dominance relationships between alleles; the number of loci involved and whether there is epistasis; whether reproduction is sexual or asexual; whether mating is random or assortative; and the relative generation times of host and pathogen and whether generations are discrete or continuous." https://lnkd.in/d3-W8NW View in LinkedIn

GENETIC DEFINITION. "We define co-evolution as the process of reciprocal, adaptive genetic change in two or more species. This simply means that changes in gene frequencies as a result of selection acting on one population create selection for changes in gene frequencies in the other population(s), although the kinds of population genetic processes that result can be different." https://lnkd.in/d3-W8NW View in LinkedIn

GENETIC COMPATIBILITY. "Theoretical studies of co-evolution date back over 40 years; examples include ‘gene-for-gene’, ‘matching allele’ and ‘matching genotype’ models. The key feature of these models is that the outcome of the host–pathogen interaction depends on the combination of host and pathogen genotypes involved." https://lnkd.in/d3-W8NW View in LinkedIn

RECIPROCITY. "The term coevolution is used to describe cases where two (or more) species reciprocally affect each other's evolution. So for example, an evolutionary change in the morphology of a plant, might affect the morphology of an herbivore that eats the plant, which in turn might affect the evolution of the plant, which might affect the evolution of the herbivore...and so on." https://lnkd.in/dY9fCZ3 View in LinkedIn

MYXOMATOSIS EXAMPLE. "The classic example is the European rabbit–myxoma virus system in which, after the virus was introduced into a naïve rabbit population, phenotypic changes were observed in both pathogen and host components of virulence. The rapid, initial attenuation of the virus presumably represents adaptation to a novel host. But subsequent slower increases in both virus pathogenicity and the ability of the host to survive infection are consistent with co-evolution." https://lnkd.in/d3-W8NW View in LinkedIn

FRAGMENT FROM NATURE for the next two weekends is on coevolution. All creatures have predators; but predation is on a spectrum of relationships that is very wide, including parasitism and symbiosis. It is probably fairer to say that all creatures have other creatures with which they interact to greater or lesser degrees. Being eaten by a lion is rather different than having athlete’s foot. But the common feature within this spectrum is how these interacting creatures coevolve. View in LinkedIn