Agricuture and Disease as Evolutionary Biology Issue

Plants

Naturally occurring variation selected from by humans - artificial selection.

Animals

For potential domestic animals, we see a suite of deisrable traits.

The winners:

Once animal is under domestication, its traits can be modified by artificial selection. - Paedomorphic traits favored to promote tractability. Consider the half-century old effort in Russia to develop pet silver foxes Tractable foxes have reduced production of adrenaline. Selecting for this requires selecting higher up on a biochemical cascade that also produce a cascading phenotypic effect that seems strangely familiar.

But domestic animals come with a down-side. Living in close association with them has provided a splendid evolutionary opportunity to their pathogens.

Disease

What are disease organisms? Pathogenic organisms in humans

  • Origins in domestic animals

    Evolutionary biology of symtoms - pathogen seeks optimum transmission strategy

    Virulence: Microbes optimize their dispersal strategy. Under some circumstances, preserving the host organism is optimal. Under others, allowing the host to die maybe optimal. E.G.:

    Crowd diseases

    Microbial evolution:

    Biodiversity as a threat

    Last week we discussed natural biodiversity as a reservoir of useful resources. Note that it is not to be taken lightly. Every time we leave the environments to which we are adapted by evolution and culture, we are going somewhere where we don't really belong. As humans expand into new habitats, we encounter new pathogens and disease vectors and take the process of transmission of diseases from animals to a new level.