Thursday, April 29, 2010
Thurs-Day 1
Bio - we focused on two examples of evolution via natural or artificial selection:
the evolution of the peppered moth as its environment was changed by the soot produced during industrial development in the early 1900's. Here, the SELECTING AGENTS, the BIRDS (the ones that DIRECTLY determine whether a given type of moth was more likely or less likely to live) went from more easily seeing and eating the darker colored moths (due to the lighter lichen-rich forest background) to more easily seeing and eating the lighter colored moths when the environment changed to a darker soot-polluted forest background.
We then discussed the increase in the percentage of insecticide X resistance in a population of locusts due to the spraying of SELECTING AGENT insecticide X. If there were NO pre-existing locusts that had alleles that made them resistant to X, then the insecticide would likely eliminate ALL of the locusts- HOWEVER, due to the variety from mutations and sexual reproduction, SOME of the locusts ALREADY HAD insecticide-X RESISTANCE alleles and the proteins that the alleles coded for. These HIGH-ADAPTIVE VALUE were not killed by X, and were more likely to survive and reproduce to pass on their resistance alleles; thus the population of locusts EVOLVED into a greater percentage of insecticide-X resistant locusts!
AP Chem - we worked out several problems in which we calculated Ecell under NON-STANDARD conditions.We focused on the "other" type of electrochemical cell: the ELECTROLYTIC CELL.
We covered the setup and sign conventions for this cell in which non-spontaneous reactions are driven by an external voltage source/battery. Only one cell/container is necessary and no salt bridge is required because the connected battery insures a steady flow of electrons.
We did several quantitative problems involving masses/moles of a metal reduced at the cathode or moles/volume of a gas produced at the anode. We added one other step to these problems by accounting for the efficiency of the battery, which affects the quantity of charge delivered per second.
the evolution of the peppered moth as its environment was changed by the soot produced during industrial development in the early 1900's. Here, the SELECTING AGENTS, the BIRDS (the ones that DIRECTLY determine whether a given type of moth was more likely or less likely to live) went from more easily seeing and eating the darker colored moths (due to the lighter lichen-rich forest background) to more easily seeing and eating the lighter colored moths when the environment changed to a darker soot-polluted forest background.
We then discussed the increase in the percentage of insecticide X resistance in a population of locusts due to the spraying of SELECTING AGENT insecticide X. If there were NO pre-existing locusts that had alleles that made them resistant to X, then the insecticide would likely eliminate ALL of the locusts- HOWEVER, due to the variety from mutations and sexual reproduction, SOME of the locusts ALREADY HAD insecticide-X RESISTANCE alleles and the proteins that the alleles coded for. These HIGH-ADAPTIVE VALUE were not killed by X, and were more likely to survive and reproduce to pass on their resistance alleles; thus the population of locusts EVOLVED into a greater percentage of insecticide-X resistant locusts!
AP Chem - we worked out several problems in which we calculated Ecell under NON-STANDARD conditions.We focused on the "other" type of electrochemical cell: the ELECTROLYTIC CELL.
We covered the setup and sign conventions for this cell in which non-spontaneous reactions are driven by an external voltage source/battery. Only one cell/container is necessary and no salt bridge is required because the connected battery insures a steady flow of electrons.
We did several quantitative problems involving masses/moles of a metal reduced at the cathode or moles/volume of a gas produced at the anode. We added one other step to these problems by accounting for the efficiency of the battery, which affects the quantity of charge delivered per second.
# posted by C @ 5:12 PM 
