Do Now: 1) Pass forward Regents Review questions 2) How does meiosis lead to increased genetic diversity in the offspring?

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Do Now 1) Pass forward Regents Review
questions2) How does meiosis lead to increased
genetic diversity in the offspring?
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Sources of Variation in Meiosis1)
Homologous Chromosomes line up randomly during
metaphase2) Crossing Over
http//www.youtube.com/watch?vjdQeKjEsj0U
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Chromosomal Mutations

• Polyploidy condition where cells have multiple
  copies of chromosome
• 3n, 5n, 5n, etc

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Karyotype- complete picture of the chromosomes in
a human
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Nondisjunction homologous chromosomes fail to
separate

• Trisomy three copies of a chromosome
• Trisomy 21 results in Down Syndrome

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http//www.youtube.com/watch?vycrPCTP2mFENR1
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AIM How can the frog reproduce?
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Amphibians

• Lives in water as a larva and on land as an adult
• Lay eggs in water
• cold-blooded
• Moist skin

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Necessary for Reproduction

• 1) Production of gametes (oogenesis and
  spermatogenesis)
• 2) Fertilization (Union of egg and sperm)
• 3) Providing for the needs of the zygote

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Amphibian Reproduction

• Egg cell
• Ovary?
• oviduct
• Cloaca
• Sperm cell testes
• ? Sperm duct ? cloaca

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Amphibian Reproduction

• Male climbs
• onto the females
• back
• Females release
• eggs externally

http//www.youtube.com/watch?vA1FWQvaBoRgfeature
related
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Sperm Flagellum
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External Fertilization

• Fertilization is by chance
• Survival is threatened
• Male produces many sperm surrounded by protective
  jelly layer

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Adaptations to Reproduction in Water

• Gametes survive longer
• Many gametes produced
• Sperm may stick to egg mass
• Colorful Eggs
• Courting Behavior

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Work together. Relate Number of Eggs produced to
parental care
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Problems Facing the Zygote

• Protection
• Regulating temperature
• Food
• Oxygen
• Water
• Managing Wastes