Reproduction Two types: 1. ASEXUAL ~ _____________ parent passes complete _____________ _____________ fission, _____________, budding, parthenogenesis **OFFSPRING GENETICALLY _____________ AS PARENT** 2. SEXUAL ~ _____________ parents pass _____________ to make genetically _____________ offspring Fertilization = two _____________ fuse to form _____________ Sex cells = _____________ cells (body cells = _____________ cells) **OFFSPRING GENETICALLY _____________ FROM PARENT** Germ cells Haploid ~ has _____________ set of chromosomes (23 for humans) Somatic cells Diploid ~ has _____________ sets of chromosomes (46 for humans) Homologous chromosomes ~ _____________ in size & shape & genes Meiosis 1) Meiosis takes a cell with ______ copies of every chromosome (_____________) and makes cells with a ________ copy of every chromosome (_____________). (This is a good idea if you’re going to combine two cells to make a new organism.) This trick is accomplished by halving _____________number. In meiosis, _______ diploid cells produces __________ haploid cells. 2) Meiosis ___________ the specific forms of each ______ that each sex cell (egg or sperm) receives. This makes for a lot of genetic __________. This trick is accomplished through _______________ ________________ and ___________________________. Genetic diversity is important for the ______________ of ________________ and ____________. Why do we need meiosis? Meiosis is necessary to __________ the number of _______________ going into the sex cells Why do this? At ____________ the male and female sex cells will provide ½ of the chromosomes each – so the offspring has genes from ___________ parents

Parent cell – chromosome pair Chromosomes copied 1st division - pairs split 2nd division – produces 4 gamete cells with ½ the original no. of chromosomes Meiosis I : Separates Homologous Chromosomes Interphase Each of the chromosomes _____________ The result is two genetically identical sister _______________ which remain attached at their _______________ Prophase I _________________ PHASE! During this phase each _____________ of chromatids don’t move to the equator alone, they match up with their __________ pair and fasten together (synapsis) in a group of four called a _________. Extremely _________________!!! It is during this phase that crossing over can occur. Crossing Over is the _______________ of ___________ during _____________. Crossing-over multiplies the already huge number of different _______ types produced by independent assortment. During ______________ I, homologous chromosomes line up next to each other. Crossing-over happens when one _______ of a _____________ crosses over the arm of the other chromatid. The chromosomes __________ and ___________. Metaphase I The _______________ line up at the ____________ attached by their _____________ to _______________ fibers from ________________. --Still in _________________ pairs

Anaphase I -The _________________ guides the movement of the ____________________ toward the poles -Sister ____________ remain _______________ -Move as a ________ towards the same __________ -The ______________ chromosome moves toward the ___________ pole -_____________ mitosis – chromosomes appear as ____________ instead of __________ (meiosis) Telophase I -This is the end of the first ____________ cell division. -The _______________ divides, forming two new __________ cells. -Each of the newly formed cells has __________ the number of the _________ cell’s chromosomes, but each ____________ is already _______________ ready for the ___________ meiotic cell division. Cytokinesis -Occurs simultaneously with _______________ I -Forms 2 __________ cells -Plant cells – __________ _____________ -Animal cells – _____________ _____________ -NO FURTHER REPLICATION OF GENETIC MATERIAL PRIOR TO THE SECOND DIVISION OF MEIOSIS Meiosis II : _________________ sister chromatids Proceeds similar to _______________ THERE IS NO INTERPHASE II! Prophase II Each of the daughter cells forms a spindle, and the ___________ stranded chromosomes move toward the equator. Metaphase II The ______________ are positioned on the ____________ plate in a ____________-like fashion. Anaphase II The _______________ of sister ____________ finally separate. The sister chromatids of each ___________ move toward _____________ poles. Now ______________ chromosomes.

Teleophase II and Cytokinesis ____________ form at opposite __________ of the cell and _______________ occurs After completion of cytokinesis there are ___________ daughter cells All are _____________ (n) One Way Meiosis Makes Lots of Different Sex Cells (Gametes) – Independent Assortment Independent assortment produces ____ distinct ______, where n = the number of unique _________________. In humans, n = _______ and _______ = ________________ That’s a lot of diversity by this mechanism alone. The Key Difference Between Mitosis and Meiosis is the Way Chromosomes Uniquely Pair and Align in Meiosis Meiosis – division error Meiosis error—fertilization Should the _________ with the chromosome pair be __________then the offspring will not be ‘_________’. In humans this often occurs with the ______ pair – producing a child with ___________ Syndrome

Summary ____________ types of ____________ : - ____________ ____________ occurs in ____________, not somatic cells; it results in genetic diversity Meiosis has 8 parts: ____________