Learning From the Fossil Record Grade 8 Science Name: Jack Mohen Date: 3/109/11 Mutations Part 1: Use the following websites to learn about mutations. http://learn.genetics.utah.edu/archive/sloozeworm/index.html 1. What is a mutation? It is a change in the DNA sequence that is there permanently Permanent change in genes Self and offspring Aa= long or short arms due to mutation you get Ab= no arm Change means it becomes something different or disappears 2. How are mutations inherited? If the parent has a mutation, the mutation is passed down through reproduction to the offspring Random it can but doesn’t necessarily pass on the gene If a parent has a mutation the offspring can get that trait 3. How are mutations acquired? Mutations are acquired when the DNA is damaged by environmental damages, when mistakes occur when the cell is copied prior to cell division Cells make a mistake when copying genes during cell division Usually happens due to an environmental factor Environmental factor: Radiation Smoking Chemicals Excessive exposure to the sun Drugs Pollution http://evolution.berkeley.edu/evosite/evo101/IIIC3Causes.shtml 1. Describe two situations where mutations can happen? 2. Why can some mutations be inherited while some are not inherited? Learning From the Fossil Record Grade 8 Science Name: Jack Mohen Date: 3/109/11 Inherited Not inherited If the mutation is in sperm and egg it will be inherited Not inherited if mutation is in body not in sperm Are mutations good or bad They are both If the trait does not help it in the environment It is good if it does help it in its evironment Part 2: Using Punnett Squares to predict and follow mutations. 1. A heterozygous dominant black moth is crossed with a homozygous recessive white moth. Cross these and predict the offspring. 2. The DNA in the recessive gene for white color is mutated by chemicals found in the smog from a factory where the moth lives. This mutation causes the gene to show recessive brown instead of recessive white in only one moth. So now, even though the one moth is white it carries a recessive gene for brown. Cross the mutated homozygous white moth with a heterozygous black moth and predict the offspring. a. Do all the offspring get this mutation? Why or why not? b. Will there still be white moths in the population? c. Will there still be black moths in the population? 3. Summarize how mutations can be passed on and cause changes in a population of organisms.