Friday, May 2, 2008
Fri-Day 2
Bio- we looked at some of the causes of variation that can lead to speciation. We recalled how mutation and genetic recombination of alleles via sexual reproduction cause variation within a species. If a relatively SMALL group of members of a species migrates to a new environment with different conditions/"selecting agents"/ "selection pressures", then "GENETIC DRIFT" is likely to occur. Genetic drift is a relatively large change in the frequency/percentage of an allele within the population and this occurs often when only a few of a small group of members are the only ones reproducing. Since the allele percentages rapidly change in just a few generations, evolution rapidly occurred.
If genetic drift occurs due to GEOGRAPHIC ISOLATION, the migrated population that is relatively rapidly evolving MAY become a separate species from the original (non-migrating) population because they can no longer interbreed due to the evolutionary changes between the two populations.
REPRODUCTIVE ISOLATION has occurred when the members of a migrating species have evolved away from the original population to such a degree that they can no longer interbreed due to physical, behavioral (mating "signals"), or genetic differences that had gradually accumulated.
Chem 7/8- we discussed other characteristics of acids and then we discussed bases.
We then did an activity that showed the range of three colors that each acid-base indicator can have depending on the pH of the aqueous solution.
Chem 9- we discussed other characteristics of acids and then we discussed bases.
If genetic drift occurs due to GEOGRAPHIC ISOLATION, the migrated population that is relatively rapidly evolving MAY become a separate species from the original (non-migrating) population because they can no longer interbreed due to the evolutionary changes between the two populations.
REPRODUCTIVE ISOLATION has occurred when the members of a migrating species have evolved away from the original population to such a degree that they can no longer interbreed due to physical, behavioral (mating "signals"), or genetic differences that had gradually accumulated.
Chem 7/8- we discussed other characteristics of acids and then we discussed bases.
We then did an activity that showed the range of three colors that each acid-base indicator can have depending on the pH of the aqueous solution.
Chem 9- we discussed other characteristics of acids and then we discussed bases.
# posted by C @ 1:38 PM 
