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POSITIVE SELECTION. “Geneticists know that human populations evolve in the face of disease. Certain versions of our genes help us fight infections better than others, and people who carry those genes tend to have more children than those who don’t. So the beneficial genetic versions persist, while other versions tend to disappear as those carrying them die. This weeding-out of all but the best genes is called positive selection.” https://lnkd.in/gWy9UtF View in LinkedIn

THE OLD AND WEAK. “Scientists long believed that the Black Death killed indiscriminately. But DeWitte's previous research found the plague was like many sicknesses: It preferentially killed the very old and those already in poor health.” https://lnkd.in/ggGWR4A View in LinkedIn

LAG PHASE. “It took some time for people to recognize that a terrible epidemic was breaking out among them and for chroniclers to note this. The timescale varies: in the countryside it took about forty days for realisation to dawn; in most towns with a few thousand inhabitants, six to seven weeks; in the  cities with over 10,000 inhabitants, about seven weeks, and in the few metropolises with over 100,000 inhabitants, as much as eight weeks.” https://lnkd.in/gZz5b2U View in LinkedIn

SHIP RATS. “Importantly, plague was spread considerable distances by rat fleas on ships. Infected ship rats would die, but their fleas would often survive and find new rat hosts wherever they landed. Unlike human fleas, rat fleas are adapted to riding with their hosts; they readily also infest clothing of people entering affected houses and ride with them to other houses or localities. This gives plague epidemics a peculiar rhythm and pace of development and a characteristic pattern of dissemination.” https://lnkd.in/gZz5b2U View in LinkedIn

TWENTY THREE DAYS. “The infection takes three–five days to incubate in people before they fall ill, and another three–five days before, in 80 per cent of the cases, the victims die. Thus, from the introduction of plague contagion among rats in a human community it takes, on average, twenty-three days before the first person dies.” https://lnkd.in/gZz5b2U View in LinkedIn

CONTEMPORARY ACCOUNT: “in many places in Siena great pits were dug and piled deep with the multitude of dead [...] And there were also those who were so sparsely covered with earth that the dogs dragged them forth and devoured many bodies throughout the city.” https://lnkd.in/gZz5b2U View in LinkedIn

MALE CAUSE OF DEATH. "Leucadendron xanthocomus. In contrast, the seed set and survival of females was not associated with display size. The ultimate cause of death in male plants appears to be the high maintenance cost of the abundant yellow non-photosynthetic display leaves that attract pollinators, but which cause considerable shading of photosynthetic leaves." https://lnkd.in/ge7JD6J View in LinkedIn

SOCIAL IMPACT. “In 1348, the Black Death swept across Europe and killed nearly 50% of the population. Immediately prices for labor, livestock, and consumables skyrocketed and governments everywhere ground to a halt. England was no exception as King Edward III had the additional concern of paying for his military campaigns against France during the opening phase of the Hundred Years War (1337-1453).” https://lnkd.in/g5DRQJ8 View in LinkedIn

MALE REPRODUCTIVE COST. "A striking example involves Leucadendron xanthocomus in which males can produce up to 20 times more flowers than females. Bond and Maze (1999) found that the number of insect visits to male plants increased linearly with floral display size, but that increasing display size was associated with a higher probability of plant death." https://lnkd.in/ge7JD6J View in LinkedIn

STRENGTHENED SECOND RESPONSE. “This might explain why, according to historical documents, medieval plague mortality declined steeply between the initial outbreak in 1347–1351 and the second outbreak in 1361 and why mortality levels remained lower in subsequent plague outbreaks throughout the medieval and early modern periods.” https://lnkd.in/gGtSd3Y View in LinkedIn