Do Now 1. What was your favorite memory about Spring Break? 2. If you could have changed anything about Spring Break, what would it have been and why? 3. What type of cell does Mitosis affect? 4. What are the stages of Mitosis? 5. What does a cell need before it can divide?

3rd Quarter grades Overall Grades for Mrs. CL’s 2016 Bio Classes Grade Letter Number of Students A 2 B 12 C 22 D 28 F

Module 8 Meiosis Day 1 of 2

Sexual reproduction and cell division Sexual reproduction is reproduction involving two sources of genetic material (i.e. two parents). This means that offspring will be genetic combinations of the two parents.

Gametes Gametes are sex cells, such as sperm and egg. The purpose of a gamete is to fuse with another gamete to combine genetic material (fertilization). A zygote is the cell which is produced by fertilization. The zygote will develop into an embryo. Fertilization

Advantages of Sexual Reproduction: The main advantage of sexual reproduction is genetic variation. With many genetic possibilities, the likelihood of a successful combination of traits for a particular environment is high.

Disadvantages of Sexual Reproduction The disadvantages of sexual reproduction include the necessity of mating for fertilization (which requires more time) and the risks of unfavorable genetic combinations.

Sexual reproduction also relies on cell division. Meiosis is a type of cell division which produces gametes. Meiosis is a unique type of cell division because it divides the genetic material in half, allowing for fertilization. Example: Human body cells contain 46 chromosomes. In order for a zygote (fertilized egg) to contain 46 chromosomes, the sperm and egg must each contain only 23 chromosomes.

The Process Fertilization (union of the gametes) Meiosis (to produce the gametes) Mitosis is the process which allows the zygote to begin dividing. The cells also must differentiate (become different types of cells to carry out different functions). Mitosis (necessary for growth)

Diploid Cell Recall that a gamete is very different from a somatic (body) cell. A somatic cell is diploid, which means it contains two of each type of chromosome. These chromosome pairs are called homologous chromosomes. For example, a human has 23 types of chromosomes. A human somatic cell has 23 homologous pairs (46 chromosomes)

Haploid Cell A gamete is haploid, which means it contains only one of each type of chromosome (one from each homologous pair). For example, a human egg cell contains 23 total chromosomes. Amoeba Sisters and MEIOSIS

Graphical representation of Meiosis: 46 Doubled Meiosis I 23 Doubled 23 Doubled Meiosis II 23 Single 23 Single 23 Single 23 Single

Independent Practice You may either: 1. Make a foldable demonstrating each step in Meiosis and its function OR 2. Create a poster (any size is fine) diagramming the steps of Meiosis (include a description for each step) Must include: Interphase, Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II , Cytokinesis

Do Now 1. What is the purpose of Mitosis? 2. What is the purpose of Meiosis? 3. What is the difference between the two?

Module 8 Meiosis Day 2 of 2 https://youtu.be/Pgh7--1MVbo?t=3m3s

Meiosis provides several sources of genetic variation: Crossing over occurs when the homologous pairs come together during Meiosis I. In crossing-over a part of one chromosome can switch places with the same part of the homologous chromosome. Then, when the homologous pairs are separated, each chromosome will be different than the original. Also called “genetic recombination”. https://youtu.be/-Lx0oLPnRQg?t=5m3s

Random assortment of chromosomes into daughter cells during Meiosis I allows for a mix of the chromosomes inherited from each parent. Independent Assortment Animation

Nondisjunction- when homologous chromosomes do not properly separate creating a gamete with one too many or one too few chromosomes. Nondisjunction / Fertilization Animation

Group Activity KAHOOT!!!!!!!! 27 Questions about Cell Cycle, Mitosis, and Meiosis https://play.kahoot.it/#/k/b3b7306c-0bd2-4398-be24-c9515f893dc0

Complete the Mitosis and Meiosis Comparison Sheet Independent Activity Complete the Mitosis and Meiosis Comparison Sheet