Transcript Meiosis and Mendel

Meiosis and Sexual Reproduction
Chapter 11-4: Meiosis
Chapter 39-3 and 4: Reproduction
and Development
Reproduction at different levels
of Organization
• Cellular Level - How does the formation
and recombination of gametes lead to
diversity?
• Organism Level - What structures are
involved in the the formation of gametes
and their recombination during fertilization?
Terms
• Mitosis copies somatic cells.
– 2N=2 copies of each chromosome
– “Diploid”
• Meiosis makes gametes or sex cells.
– 1N=1 copy of each chromosome.
– “Haploid”
Mitosis vs.
Meiosis
Details of
Meiosis
• Be able to describe
the alignment of
chromosomes
• DNA vocab
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Homologous
Tetrad
Crossing over
Sister chromatids
Review of
Meiosis
• Makes haploid
cells
• Meiosis I:
Homologous
Chromosomes
Separate
• Meiosis II: Sister
Chromatids
Separate
Mistakes during Meiosis:
Nondisjunction is Violation of
the Law of Segregation
Advantages of Sexual
Reproduction
Three Ways Meiosis Creates Diversity
1. Law of Independent Assortment
2. Crossing Over
3. Random Fertilization
Law of Independent Assortment
Demonstrate
• 5 boys; 5 girls: Homologous Chromosomes
• Line up at Metaphase I
• How many different ways can you line up?
• Crossing over…change shoes with your partner
(you can hold them if you don’t want to wear
them).
• Imagine these “chromosomes” are made of DNA.
What does independent assortment do? Crossing
over?
Crossing Over:
Prophase/Metaphase I: Tetrad
Random Fertilization
• How does random
fertilization lead to
diversity?
Sexual Life Cycles
Human Reproduction--Male
•
Structures:
•Testes
•Scrotum
•Vas Deferens
•Prostate
•Urethra
•Penis
Human Reproduction--Female
Structures:
• Ovaries
• Fallopian Tubes
• Uterus
• Cervis
• Vagina
Cellular Organization-Spermatogenesis
Cellular Organization--Oogenesis
Fertilization--An example of
structure meeting function
In vitro fertilization…and the
ethics of cloning
• Why is IVF used?
• Cloning vs. Stem Cell
Therapies
• Use of cloning to
produce Genetically
Modified Organisms
or GMO’s
Development: Mitosis and
Differentiation
Three Layers develop their
“fates” early
• Ectoderm: Skin and Nervous System
• Endoderm: Lining of Organs including
digestive system
• Mesoderm: Muscles and Bones
Developmental Terms
• Egg: 14 days before fertilization an egg is
ready to be fertilized
• Embryo: Fertilization until 9 weeks of
development
• Fetus: Development 9 weeks until birth
(term used in humans and some animals)
“Miracle of Life”
• We will watch the Miracle of Life to
understand the organization of sexual
reproduction in humans.
• On your notecard, write questions that you
have and we will spend part of a class
discussing questions that relate to the
biological process of reproduction.