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Old 07-22-2009, 08:46 PM   #21
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Location: NE IL, USA

While I am sorry for these losses....these are natural losses. Some years are better than others. Thrushes, song sparrows, and wrens didn't have a good year, either. This is how it goes.
"The only thing we have to fear is fear itself.....and spiders." Me and Franky D.
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Old 07-30-2009, 07:53 PM   #22
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Default Yet another challenge confronting PM Landlords

English House Sparrow- Examples of microevolution

Examples of microevolution
excerpts from above:
The size of the sparrow

House sparrows were introduced to North America in 1852. Since that time, the sparrows have evolved different characteristics in different locations. Sparrow populations in the north are larger-bodied than sparrow populations in the south. This divergence in populations is probably at least partly a result of natural selection: larger-bodied birds can often survive lower temperatures than smaller-bodied birds can. Colder weather in the north probably selects for larger-bodied birds. As this map shows, sparrows in colder places are now generally larger than sparrows in warmer locales.
Evolving resistance

Science has documented many examples of the evolution of resistance of pests to pesticides, weeds to herbicides, and pathogens to medicines all of which are cases of microevolution by natural selection. In the case of antibiotic resistance, for example, a bacterial strain's huge population size and short generation time mean that natural selection acts quickly. In each bacterial generation, new mutations and gene combinations are generated. If any of these confer resistance to a drug to which the bacteria are exposed, natural selection will favor those gene versions. Over the course of many bacterial generations (a small fraction of a single human lifetime), the bacteria adapt to our defenses, evolving right out from under our attempts to rid ourselves of them.
The tendency of man's nature to good is like the tendency of water to flow downwards.
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bird, bird deaths, birds in decline, birds in winter, feeding purple martins, house sparrows, invasive birds, martin attraction, martins, microevolution, midwest, midwest purple martins, purple, purple martins, sparrows, wiped

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