You may think humans are changing to adapt to city life. However, animals living in cities are evolving faster. Metabolisms of the little creatures are running hot. In Puerto Rico, anole lizards can travel across concrete due to changes in their feet structure.
Charles Darwin did get things wrong. Evolution does not just happen over tens of thousands of years. It is dynamic. Alterations are rapid. PCB (Polychlorinated Biphenyls) levels rise in cities and it will kill some animals. The mummichog fish has quickly evolved to survive the poisonous chemical.
The shorter the lifespan of living organisms the faster they evolve. A long-time resident of cities is the European blackbird. It has developed more practical beaks and songs. Moreover, their digestive system can digest food scraps discarded by people. Urban blackbirds no longer migrate.
Mosquitoes in the London Underground have changed dramatically. They breed one-on-one, not in the clouds of mozzies in a sexual frenzy like their forebears. No blood meal is required before eggs are laid. Different rail lines have their own types of mosquito.
Coyotes wander the streets of Chicago, going to rooftops to raise their young. New York mice no longer succumb to fatty foods thrown away by humans. Because people are kept alive by modern medicine we hardly evolve at all. Eating take away food does not kill us before the age of procreation.
Mosquitoes in the London Underground have changed dramatically. They breed one-on-one, not in the clouds of mozzies in a sexual frenzy like their forebears. No blood meal is required before eggs are laid. Different rail lines have their own types of mosquito.
Coyotes wander the streets of Chicago, going to rooftops to raise their young. New York mice no longer succumb to fatty foods thrown away by humans. Because people are kept alive by modern medicine we hardly evolve at all. Eating take away food does not kill us before the age of procreation.
◆ BIOLOGY ◆
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