9-3-09 - Ecology 330 Class Notes First reading The data...

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Ecology 330 – Class Notes – 9/3/09 First reading – The data supports the hypothesis Downing La Mantagne: * Haobordiae – aquatic predator The adults don’t live long 90% of life is aquatic larval form They live in lakes o Part of niche dimension is temperature o Author’s use altitude (lake elevation) as a surrogate for temperature (3 mins in) o 1000 m increase, 10 degrees Celsius cooler There is a range of temperatures at any given elevation If you look at temperature and the percentage of the lakes that contain these three species, puntipennis is only in the warmest of lakes, while the other three are in the lakes that are substantially cooler Certainly distinct preferences Puntipennis o Warm lakes at lower elevations Temperature is a niche dimension Lake elevation is a niche dimension Distinct Paleoecology Applications of the Data in this experiment o Take a sediment core (sample) and you found a change in the species, you could make an inference based the different head cores of the larvae (they are made of chitin) o If you found any sort of data in the soil, you could make inferences Chitienized head capsules At the time, these sediments were positive, we know the climate was cooler at the time because the cooler lakes only support ( this ) species Downing: Mussels – prefer sandier substrates rather than the muddy substrate o If they are in the mud, they sink (because they are heavy) Greater Fraction of the mussels found in mud At the start of the experiment, half were in mud and half were in sand
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o The scientists set up this experiment. o The result : the mussels had a distinct preference to go to the mud, even though sand is the more desirable environment o Those in the mud could move just as easily as those in sand o In real life, the mussels generally choose a sandier substrate o If we find species in a specific niche in real life, in their natural niche, we HAVE TO BE CAREFUL about translating the properties of the niche in their natural environment to A DIFFERENT NICHE (or in the laboratory) It’s difficult to burrow into gravel and sand, but it’s easier to burrow in mud to get out of sight The scientists could be altering different characteristics of the environment not necessarily taken into account in affecting the mussels’ decision Another example: There were sandy deposits found in French Creek Mussels burrowed in the sand Apparently the mussels had the ability to discriminate against the different
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9-3-09 - Ecology 330 Class Notes First reading The data...

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