7.4 Collective Advantage
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sion of labor between well-fed defenders and undernourished folk inside increases
resilience to outside threats – but the bacterial community also contrives to prevent
mass starvation in quiet times. Outside cells periodically stop proliferating, letting
more nutrients penetrate inward, and this leads to growth oscillations of the kind
shown in the right-hand panels of Fig. 7.6.
Cooperation among cells is indeed the bacterial alternative to integrating into
a multicellular organism, and might have been the precursor of the transition to
multicellularity. But is it as efficient? Bacterial chemical communication is not directed to specific cells. It lacks a structure. Different bacteria care for themselves
rather than for the biofilm as a whole, which may benefit from their actions only
unwittingly, not unlike human society benefitting from the egoistic behavior of its
members. Bacterial, like human, societies may suffer from the “tragedy of the commons”, overconsumption of public goods. And bacteria would not commit suicide,
emulating the apoptosis of organismal cells.
Bacteria may specialize within a cluster or a colony, and, going further, specialization and cooperation among clusters may also be possible. Biofilms possess
some mechanical integrity but it is hard to imagine them developing a kind of muscle without integrating into a single organism. Muscles should be coordinated and
controlled, and control implies not just the ability to communicate, but communications sent to a precise address. This kind of control is directed by genes in cells,
by nerve networks in animals, and by social or government regulations in animal
bands or human tribes, communities, or polities, but it cannot be maintained in an
unstructured assembly.
7.4 Collective Advantage
Collective interactions without integrating into a single body develop not only
among cells but among multicellular organisms. I mentioned the hydrodynamic advantages of fish shoals and bird flocks. Those are temporary and weakly interacting
assemblies, generally defined as swarms. It is also often said that swarming provides
defence from predators, so-called “safety in numbers”. I doubted it when watching a
film by David Attenborough showing predator fish and dolphins feasting on a shoal
of herring, until “there were none”. Land predators are commonly not as numerous
and have a limited appetite, so that brawny wildebeests or deer may indeed feel
safer in a herd because it is their weaker relatives who will be eaten. More likely,
kin vertebrates herd and swarm just because they have common tastes.
Stronger cooperation is rare among animals, and in mammals, not counting humans, it goes no further than extended family groups hunting or foraging together.
Among insects, only ants, termites, bees, and some wasps have developed tightly
structured communities. It is very hard to overcome the egoistic pull of individual selection. A common theory says that altruism may be driven by kin selection
propagating genes coding self-sacrificing behavior. The prominent biochemist John
Holden reportedly said that he was prepared to lay down his life for eight cousins
113
sion of labor between well-fed defenders and undernourished folk inside increases
resilience to outside threats – but the bacterial community also contrives to prevent
mass starvation in quiet times. Outside cells periodically stop proliferating, letting
more nutrients penetrate inward, and this leads to growth oscillations of the kind
shown in the right-hand panels of Fig. 7.6.
Cooperation among cells is indeed the bacterial alternative to integrating into
a multicellular organism, and might have been the precursor of the transition to
multicellularity. But is it as efficient? Bacterial chemical communication is not directed to specific cells. It lacks a structure. Different bacteria care for themselves
rather than for the biofilm as a whole, which may benefit from their actions only
unwittingly, not unlike human society benefitting from the egoistic behavior of its
members. Bacterial, like human, societies may suffer from the “tragedy of the commons”, overconsumption of public goods. And bacteria would not commit suicide,
emulating the apoptosis of organismal cells.
Bacteria may specialize within a cluster or a colony, and, going further, specialization and cooperation among clusters may also be possible. Biofilms possess
some mechanical integrity but it is hard to imagine them developing a kind of muscle without integrating into a single organism. Muscles should be coordinated and
controlled, and control implies not just the ability to communicate, but communications sent to a precise address. This kind of control is directed by genes in cells,
by nerve networks in animals, and by social or government regulations in animal
bands or human tribes, communities, or polities, but it cannot be maintained in an
unstructured assembly.
7.4 Collective Advantage
Collective interactions without integrating into a single body develop not only
among cells but among multicellular organisms. I mentioned the hydrodynamic advantages of fish shoals and bird flocks. Those are temporary and weakly interacting
assemblies, generally defined as swarms. It is also often said that swarming provides
defence from predators, so-called “safety in numbers”. I doubted it when watching a
film by David Attenborough showing predator fish and dolphins feasting on a shoal
of herring, until “there were none”. Land predators are commonly not as numerous
and have a limited appetite, so that brawny wildebeests or deer may indeed feel
safer in a herd because it is their weaker relatives who will be eaten. More likely,
kin vertebrates herd and swarm just because they have common tastes.
Stronger cooperation is rare among animals, and in mammals, not counting humans, it goes no further than extended family groups hunting or foraging together.
Among insects, only ants, termites, bees, and some wasps have developed tightly
structured communities. It is very hard to overcome the egoistic pull of individual selection. A common theory says that altruism may be driven by kin selection
propagating genes coding self-sacrificing behavior. The prominent biochemist John
Holden reportedly said that he was prepared to lay down his life for eight cousins