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MEIOSIS AND SEXUAL REPRODUCTION. WHAT ARE THE TWO TYPES OF CELL DIVISION? MITOTIC CELL DIVISION CREATE “IDENTICAL” OFFSPRING ONLY ONE PARENT CELL MEIOTIC CELL DIVISION CREATE SIMILAR, BUT DIFFERENT, OFFSPRING REQUIRES TWO DIFFERENT PARENT CELLS. MEOISIS AND SEXUAL REPRODUCTION.
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WHAT ARE THE TWO TYPES OF CELL DIVISION? • MITOTIC CELL DIVISION • CREATE “IDENTICAL” OFFSPRING • ONLY ONE PARENT CELL • MEIOTIC CELL DIVISION • CREATE SIMILAR, BUT DIFFERENT, OFFSPRING • REQUIRES TWO DIFFERENT PARENT CELLS MEOISIS AND SEXUAL REPRODUCTION
WHY HAVE TWO DIFFERENT FORMS OF CELL DIVISION? • WHY NOT JUST HAVE EVERY CELL BE “IDENTICAL” TO EVERY OTHER CELL? • IN ORDER TO MAKE “DIFFERENT” CELLS, GENETIC MATERIAL NEEDS TO BE COMBINED IN DIFFERENT WAYS…HENCE, MEIOTIC CELL DIVISION • MEOISIS GAMETOGENESIS FERTILIZATION MEOISIS AND SEXUAL REPRODUCTION
IN ORDER TO UNDERSTAND MEIOTIC CELL DIVISION, WE HAVE TO UNDERSTAND A LITTLE BIT MORE ABOUT THE GENETIC INFORMATION FOUND IN CELLS MEOISIS AND SEXUAL REPRODUCTION
ALL LIVING THINGS HAVE DNA, THE BLUEPRINTS FOR LIFE, WHICH IS STORED INSIDE THE NUCLEUS IN SOME SET NUMBER OF CHROMOSOMES (THIS # IS DIFFERENT FOR DIFFERENT LIVING THINGS) MEOISIS AND SEXUAL REPRODUCTION
HOW MANY CHROMOSOMES DO HUMANS HAVE? MEOISIS AND SEXUAL REPRODUCTION
IN ORDER FOR SEXUAL REPRODUCTION TO OCCUR, TWO PARENT CELLS MUST COMBINE…BUT YOU CAN’T CHANGE THE TOTAL CHROMOSOME NUMBER IN THE CELL • THEREFORE, SOMETHING HAS TO HAPPEN TO KEEP THE SAME CHROMOSOME NUMBER AT ALL TIMES MEOISIS AND SEXUAL REPRODUCTION
DIPLOID VS HAPLOID CELLS • MOST BODY (SOMATIC) CELLS ARE DIPLOID • CONTAINING THE FULL AMOUNT OF DNA • SEX CELLS (GAMETES) ARE HAPLOID • CONTAINING HALF THE AMOUNT OF DNA MEOISIS AND SEXUAL REPRODUCTION
WHY DO YOU NEED HAPLOID CELLS? • SO WHEN THEY COMBINE, THE CORRECT CHROMOSOME NUMBER IS RESTORED • WHAT IS THE HAPLOID NUMBER IN HUMANS? • 23 • WHAT DO HAPLOID CELLS LOOK LIKE IN HUMANS? • SPERM AND EGG MEOISIS AND SEXUAL REPRODUCTION
HOW DO HAPLOID CELLS GET MADE? • MEIOTIC CELL DIVISION!!! • MEIOSIS IS ALSO CALLEDREDUCTION-DIVISION • LET’S BREAK DOWNTHE STAGES OF MEIOSIS MEOISIS AND SEXUAL REPRODUCTION
MITOSIS VS MEIOSIS MEOISIS AND SEXUAL REPRODUCTION
WHAT’S THE POINT OF MEIOTIC CELL DIVISION? • TO MAKE CELLS THAT CAN BE COMBINED TO CREATE NEW GENETIC COMBINATIONS IN OFFSPRING CELLS • WHY BOTHER WITH NEW GENETIC COMBINATIONS? • THE PROCESS OF COMBINING THESE SEX CELLS IS CALLED SEXUAL REPRODUCTION (THE FUSION OF GAMETES) MEOISIS AND SEXUAL REPRODUCTION
SEXUAL REPRODUCTION • IN BACTERIA AND PROTISTS MEOISIS AND SEXUAL REPRODUCTION
SEXUAL REPRODUCTION IN ANIMALS • ANIMALS POSSES REPRODUCTIVE SYSTEMS • SPECIALIZED STRUCTURES (GONADS) THAT PRODUCE GAMETES • MALE VS FEMALE • HERMAPHRODITE • GAMETOGENESIS • SPERMATOGENESIS • OOGENESIS • FERTILIZATION • INTERNAL VS EXTERNAL • PARTHENOGENESIS MEOISIS AND SEXUAL REPRODUCTION
WHAT HAPPENS WHEN THE SPERM AND EGG FUSE? • FERTILIZATION • ANIMAL(EMBRYONIC)DEVELOPMENT ISNEXT!! MEOISIS AND SEXUAL REPRODUCTION