I will compare mitosis and meiosis by completing a double bubble and web quest activity. Outcome

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Meiosis & Fertilization Sexual Reproduction - two individuals produce offspring that have genetic characteristics from both parents (unique – not clones!) Outcome (proposed): Distinguish between the products of mitosis and meiosis...

Meiosis The process that forms gametes (sex cells) These gametes (sex cells) are sperm and egg cells

Meiosis Chromosome number is reduced by one-half  2n  n  Diploid (2n) – 2 copies of each chromosome  Haploid (n) – 1 copy of each. End result – 4 haploid gametes

Meiosis 2 cell divisions

Chromosome Number OrganismSomatic (Body Cell) Gametes (sex cells) Human46 Kangaroo16 Pegasus

Homologous Chromosomes Each cell has 2 copies of each chromosome Homologous chromosomes  Have the same genes in the same locations

Crossing-over Homologous chromosomes exchange parts Results in genetic variation  different combinations of genes

Fertilization Combination of gametes (sperm and egg) to form zygotes Zygote – diploid (2n) cell (two copies of each chromosome) formed by two haploid cells (1n + 1n = 2n)

Quick Quiz 1. Which of these does not occur during meiosis? (2007) A production of identical gametes B production of new gene combinations C crossing-over of homologous chromosomes D reduction of chromosome number by one-half 2. Sea stars are genetically different from each other and from their parents. These genetic differences are the result of (2006) A mitosis B cloning C sexual reproduction D asexual reproduction

Practice Questions 3. Horses have 64 chromosomes in each body cell. If a horse cell undergoes meiosis, how many chromosomes should be in each gamete? (2007) A 16 B 32 C 64 D A sperm cell of a moth has 112 chromosomes. How many chromosomes are in the moth’s wing cells? (2005) A 66 B 112 C 224 D Body cell

I will compare mitosis and meiosis by completing a double bubble and web quest activity. Outcome

Web Quest! Groups will follow the directions on their paper. Stay at your assigned lab station! When you are done, there is another activity to work on.

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