Animals Are Not Malthusians
According to Malthus and Darwin, the struggle to survive favors those who have the most fitness to take advantage of limited resources. A study by the Research Institute of Wildlife Ecology in Vienna, reported by PhysOrg shows this is not the case:
Charles Darwin and his contemporaries postulated that food consumption in birds and mammals was limited by resource levels, that is, animals would eat as much as they could while food was plentiful and produce as many offspring as this would allow them to. However, recent research has shown that, even when food is abundant, energy intake reaches a limit, even in animals with high nutrient demands, such as lactating females. Scientists at the Research Institute of Wildlife Ecology in Vienna suggest that this is due to active control of maternal investment in offspring in order to maintain long-term reproductive fitness.
The research team proposed a different theory: “using energy at close to the maximum rate has costs for animals which may compromise their ability to successfully reproduce in the future.” The article did not attempt to state this goal-oriented behavior in Darwinian terms. If natural selection can favor animals that can plan ahead and conserve resources even when they are plentiful, contrary to what Darwin and Malthus assumed, then it is trying to explain opposite outcomes at the same time – the Stuff Happens Law (09/15/2008 commentary).
Why should the simplistic statistics of Malthus have been accepted as a glittering generality for all of nature? (see 03/30/2009: “Natural Selection Based on Bad Statistics”). It seemed intuitively obvious to him that resources grow linearly but reproductive competition increases exponentially, but why should that be so? Malthus was neither a mathematician nor a field naturalist, yet his simplistic (and wrong) mathematical model influenced a generation. It profoundly influenced Darwin as he formulated his simplistic theory of natural selection (06/05/2007). Someone should have questioned the intuition and tested it. It could have saved the world a lot of trouble (like communism, cutthroat capitalism, World War I and World War II).
So another simplistic Darwinian assumption has been tested and found to be wrong. Keep up the good work (08/13/2002, 04/02/2004, 05/11/2004, etc.).