Variation Objective 2

Sexual Reproduction Asexual reproduction is when one organism makes a copy of itself Cells (mitosis) Sex is an improvement of asexual reproduction Largest source of variation of life Scrambles the genes of two different organisms of the same species

Review Why is sex important?

Crossing Over Why do brothers/sisters not look identical if they are made from the same 2 parents? Crossing over is how your genes scramble together to make each egg/sperm unique from the others

Crossing Over In prophase 1 the chromosomes line up next to each other making a unique shape (tetrad)

Crossing Over While in tetrads the chromosomes will swap massive pieces of DNA Draw this step

Crossing Over While in tetrads the chromosomes will swap massive pieces of DNA Draw this step

Review What is the name of the shape chromosomes form during prophase I of meiosis? What happens to the DNA in the chromosomes while they are crossed over each other?

Mutation Mutation is a change in the genetic code Mutations are the original source of all variety on the planet Mutations fall into 2 categories Gene mutations Chromosome mutations

Review What is the original source of all variation on the planet? What is a mutation? What are the two categories of mutation?

Gene Mutations Frameshift Mutations The gene is lengthened or shortened Deletion Insertion Deletion Insertion

Gene Mutations Point Mutations Mutations at a single point in a gene Substitution Insertion Deletion Deletion Substitution Insertion

Chromosome Mutations Changes at the chromosome level Many genes can be affected Deletion Duplication Inversion Translocation Deletion Duplication Inversion Translocation

Review What are the two types of Gene Mutation? Which type of mutation effects the most genes? What is the original source of all variation? What is the largest source of all variation?