Tuesday, April 29, 2008
Tues-Day 1
Bio- we discussed two more examples of evolution of a species; in these cases, the selecting agents, pesticides and antibiotics, were "artificial"/created purposefully by humans.
We saw how a population of insects reproduce sexually, have variety via mutation and sexual reproduction, and compete for resources. However, when the new selecting agent, call it pesticide-A, is introduced, only those insects that ALREADY HAVE the alleles that code for enzymes that cause pesticide-A to break down can survive the pesticide-A spraying. These resistant insects NOW have an advantage, an ADAPTATION, to outcompete the other non-resistant insects. The surviving pesticide-A-resistant insects survive to reproduce and pass on their alleles to the offspring so that the next generations are resistant to pesticide-A . Thus, the species evolved into a pesticide-A resistant species.
We looked at a similar case for the evolution of penicillin-resistant streptococcus bacteria even though bacteria reproduce asexually; that just means that there tends to be less variety within a bacterial species though some variation occurs via mutation.
We then did a peppered-moth simulation lab in which lab partners played the birds/selecting agents.
Chem 7/8/9: We prepped for the unit exam. Check your work with the answer key and annotated review packet on Blackboard. Study hard and go all out tomorrow for a successful start to our last quarter!
We saw how a population of insects reproduce sexually, have variety via mutation and sexual reproduction, and compete for resources. However, when the new selecting agent, call it pesticide-A, is introduced, only those insects that ALREADY HAVE the alleles that code for enzymes that cause pesticide-A to break down can survive the pesticide-A spraying. These resistant insects NOW have an advantage, an ADAPTATION, to outcompete the other non-resistant insects. The surviving pesticide-A-resistant insects survive to reproduce and pass on their alleles to the offspring so that the next generations are resistant to pesticide-A . Thus, the species evolved into a pesticide-A resistant species.
We looked at a similar case for the evolution of penicillin-resistant streptococcus bacteria even though bacteria reproduce asexually; that just means that there tends to be less variety within a bacterial species though some variation occurs via mutation.
We then did a peppered-moth simulation lab in which lab partners played the birds/selecting agents.
Chem 7/8/9: We prepped for the unit exam. Check your work with the answer key and annotated review packet on Blackboard. Study hard and go all out tomorrow for a successful start to our last quarter!
# posted by C @ 7:23 PM 
