Reading quiz

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Reading quiz

• WHY sexual reproduction?
• Mixes 2 organisms traits to increase the
  likelihood of passing the BEST traits
  increasing survival of that species.
• NOT a guarantee that these BEST traits will all
  show up in 1 offspring. Its RANDOM chance.
  HOPE to get the best.
• DOES NOT CAUSE EVOLUTION
• Evolution is driven by many things and MUTATIONS
  is one of them.
• Cloning (mitosis) CAN have mutations too! Sexual
  Repo (Meiosis) speeds up passing mutations around
  which speeds up the slow process of Evolution.

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• Tell me when there is 3 minutes left so I can
  pass back the quiz.
• See me after school for questions (room 602- 300
  to 330)

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Web quest review!
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Meiosis!

• These notes will be done quickly. They are
  review of your reading web quest. Now is the
  time to ask questions. I will post these notes
  on the hw web so pay attention ask questions?

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More information on your good friends
Chromosomes!

• I.) In cells, chromosomes exist in pairs. One
  from mother and one from its father.
• A.) In humans, we have a total of 46 chromosomes.
  23 chromosomes from mom and 23 chromosomes from
  our dad.

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• 1.) Therefore, we have 23 pairs of chromosomes.
• 2.) These pairs of chromosomes are called
  HOMOLOGOUS pairs.
• a.) Same in SIZE and FUNCTION.
• b.) They have genes for the same TRAITS in the
  same order.

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• 3.) Any cell with 2 sets of chromosomes (1
  complete set from mom and 1 from dad) is called a
  DIPLOID cell.
• a.) ALL the cells in your body are diploid EXCEPT
  the GAMETES (sex cells).
• b) Gametes only have one set of chromosomes which
  means they only have 23 chromosomes SO we call
  them HAPLOID
• c. )WHY? If the chromosome wasnt halved then
  each generation the chromosome number would
  double.

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Meiosis

• I.) Specialized cells in reproductive organs
  (OVARIES in females and TESTES in males) undergo
  a form of cell division called meiosis to produce
  haploid gametes.

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Sperm/Egg

• You pass on half your genes to offspring
• You must make a gamete (sperm or egg cell) with
  half of your chromosomes
• Each gamete randomly receives 1 of the 2 versions
  of each chromosome

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Meiosis

• Each parent cell produces 4 haploid daughter
  cells
• Each daughter cell has 1 set of chromosomes
  (instead of the usual 2) OR (half of the parents
  chromosomes)

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of Possible Gametes

• There are 223 possible chromosome combinations to
  make a gamete
• 8,388,608 possibilities
• So you are 1 out of 8,388,6082 possibilities
• You are quite literally 1 in a trillion (1 of
  70,368,744,200,000 possible combinations of your
  parents)

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Which side of the cell the chromosome lines up on
223 crossing over!!!
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Whats the Point?

• Meiosis allows us to have offspring that are
  different and have a unique combination of genes
• This increases diversity in the population
• Increased diversity means increased ability for
  the species to survive and adapt to new situations

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• HW compare Mitosis Meiosis.
• Use your brain the worksheet to answer as much
  as possible.
• Consult your notes/Internet if necessary, just
  not other biology students.