PPT-Chapter 13 Meiosis and Sexual

Life Cycles Overview Variations on a Theme Living organisms are distinguished by their ability to reproduce their own kind Genetics is the scientific study of heredity and variation Heredity . Chromosomes in Reproductive Cells? Introduction Sexual reproduction is a process that creates a new organism by combining the genetic material of two organisms. There are two main steps in sexual rep Meiosis. Meiosis is the cell division which produces the . sex cells . or . gametes. .. Meiosis occurs in the cells of the . reproductive organs. :. Sperm cells – testes. Ova (eggs) – ovaries. Pollen - anthers. LECA=last eukaryotic common ancestor as distinct from LUCA (last universal com. . a. nc.). Probably had the ability to reproduce sexually…how do we know this??. Transition to a sexual LECA involved 4 and we will focus on 3 “transitions. Sexual Life Cycles. modes of reproduction. diploid/haploid and meiosis. meiosis I and meiosis II phases. key differences between mitosis and meiosis. variation in position of meiosis in life cycles. why sex?. Before we start genetics, let's review the process of what makes us all look different compared to our siblings, family, and classmates!. Sexual Reproduction. Sexual reproduction creates genetic variability. That is why we all look different and you look different from your siblings! . Variations on a Theme. Living organisms are distinguished by their ability to reproduce their own kind. Heredity . is the transmission of traits from one generation to the next. Variation . is demonstrated by the differences in appearance that offspring show from parents and siblings. Review of Mitosis. Mitosis is a form of . asexual reproduction. This means that it . only requires 1 organism . (ex. Skin cells dividing). For growth and repair in . somatic. (body) cells!. Results in 2 cells identical to the original (parent) cell. 10.2 – Meiosis Sexual Reproduction Function: creates gametes (sperm, egg, pollen) for sexual reproduction . Meiosis: Cell division for sexual reproduction. Males - testes Females - ovaries Sex Cells Where do you come from?. Sex: . Woman, XX. . Man, XY. Gender: Female Male. . Egg, Ovum Sperm. Fertilization – union of sperm an egg to produce zygote . Illustrate the steps of meiosis. Describe the roles of crossing over and independent assortment in meiosis . Explain the importance of meiosis to living organisms. Words to know. Crossing over. - the process by which genetic material is exchanged by non-sister chromatids during prophase I of meiosis. Cell division / Asexual reproduction. Mitosis. produce cells with same information. identical daughter cells. exact copies. clones. same amount of DNA . same number of chromosomes. same genetic information. Let’s Review!. The cell cycle is when . a cell makes a copy of itself . for:. Growth, Repair, Replacement. BODY (autosomal/somatic) cells reproduce . by . mitosis. s. ome . organisms . do also, . but we will talk about that . Defined. : Gametes from two separate parents unite. Meiosis: Diploid (2n) to haploid (n) cells . Mechanism that allows for . genetic diversity. Many eukaryotes reproduce in this manner. Plants, animals and fungi. In asexual reproduction, a single individual gives rise to offspring that are identical to itself and . others [MITOSIS]. Bacteria reproduce asexually. Most plants and some simple animals can reproduce both asexually and .