Reproduction of Organisms

Sexual Reproduction Sexual Reproduction Type of reproduction in which the genetic material from two different cells combine, producing an offspring

Sexual Reproduction Egg Sperm Female sex cell Male sex cell Forms in ovary Sperm Male sex cell Forms in testis

Sexual Reproduction Fertilization An egg and sperm cell join together

Sexual Reproduction Zygote New cell that forms from fertilization Goes through cell cycle Forms two kinds of cells Body cells Sex cells

Sexual Reproduction Body Cells Allow organism to grow Called diploid

Sexual Reproduction Body Cells Have chromosomes that occur in pairs Homologous chromosomes Have genes for the same traits arranged in the same order Different organisms have different numbers of chromosomes Too many or too few chromosomes causes a zygote to not develop properly

Sexual Reproduction Sex Cells Allow organism to reproduce Called haploid Have only ONE chromosome from each pair

Sexual Reproduction Meiosis Occurs only in formation of sex cells One diploid cell divides and makes four haploid sex cells Meiosis ensures that chromosome numbers of a species stay the same

Sexual Reproduction Fertilization Egg Sperm Zygote Mitosis MEIOSIS

Sexual Reproduction Characteristic Meiosis Mitosis NUMBER OF CHROMOSOMES IN PARENT CELL DIPLOID TYPE OF PARENT CELL SEX (REPRODUCTIVE) BODY NUMBER OF DIVISIONS OF NUCLEI TWO ONE NUMBER OF DAUGHTER CELLS FOUR IN DAUGHTER CELL HAPLOID FUNCTION FORMS SPERM AND EGG CELLS GROWTH REPAIR

Sexual Reproduction

Sexual Reproduction

Sexual Reproduction

Sexual Reproduction Prophase I Nuclear membrane breaks apart Chromosomes condense and form homologous pairs

Sexual Reproduction Metaphase I Homologous chromosomes line up in the center of the cell Spindle fibers attach to each chromosome

Sexual Reproduction Anaphase I Homologous chromosomes separate and are pulled to opposite ends of the cell

Sexual Reproduction Telophase I Nuclear membrane forms around each set of chromosomes The cytoplasm divides, forming two daughter cells

Sexual Reproduction Prophase II Nuclear membrane breaks apart

Sexual Reproduction Metaphase II Sister chromatids line up along the center of the cell

Sexual Reproduction Anaphase II Sister chromatids of each chromosome begin to separate and are pulled to opposite ends of the cell

Sexual Reproduction Telophase II A nuclear membrane forms around each set of chromatids The cytoplasm divides

Sexual Reproduction Advantages Genetic Variation Allows for individual differences May be an advantage if the environment changes Selective Breeding Used to develop plants and animals with desirable traits Disadvantages Time and energy

asexual Reproduction One parent organism produces offspring without meiosis and fertilization Advantages Can rapidly reproduce Can reproduce without a mate Disadvantages Genetically identical offspring—no genetic variation Harmful mutations passed on

asexual Reproduction Fission Cell division in prokaryotes that forms two genetically identical individuals EX: E. Coli

asexual Reproduction Mitotic cell division Unicellular eukaryotes reproduce through mitosis and cell division EX: amoeba

asexual Reproduction Budding A new organism grows by mitosis and cell division on the body of its parent Bud is genetically identical to parent EX: hydra

asexual Reproduction Animal regeneration Producing new offspring Offspring are genetically identical EX: planarian

asexual Reproduction Animal regeneration Producing new body parts Not asexual reproduction Regenerates lost or damaged body parts EX: sea star

asexual Reproduction Vegetative regeneration Offspring grow from part pf a plant Usually involves structures such as roots, stems, and leaves Offspring are genetically identical EX: strawberries

asexual Reproduction Cloning Performed in a laboratory Produces identical individuals from a cell or a cluster of cells taken from a multicellular organism

asexual Reproduction Plant Cloning Animal Cloning Uses tissue culture to make plants with desirable traits or without disease Animal Cloning Genetic copy of its parent May save animals from extinction Concerns about ethical issues