Animal Reproduction
AP Big Ideas:
#3: Genetics and Information Transfer
#2: Complex Processes and Homeostasis
#1 Evolution
Goals:
• Review meiosis & advantages of sexual
Reproduction.
• Analyze crossing over data and calculate
crossover frequency.
• Explain the mechanisms of animal
reproduction.
Meiosis
Crossing Over
Similar to Mitosis?
Homologous chromosomes
Sister Chromatids
3 Ways Sexual Reproduction increases
variation
Crossing Over
• Sordaria lab
activity
– What is an
ascospore?
– What evidence
do ascospores
provide for
crossing over?
– How do you
calculate
crossover
frequency
Mendel’s Laws
• Law of Segregation
• Law of Independent Assortment
• Mendel’s observations support the idea that
genes are located on chromosomes!
Gene & Allele
Law of Segregation
Autosomes
Sex
Chromosomes
Haploid (n)
Diploid (2n)
Are X and Y
universal?
Is XX always
female and XY
always male?
Chromosome modification at the DNA
level
X-inactivation
• Barr body
• DNA methylation
• Happens during migration of cells in
development. Random!!!
Lack of segregation…
• Aneuploidy
Lack of Segregation…
• Polyploidy
– Plant
speciation
Mendel’s Law of Independent
Assortment
Formative Assessment #1
• Two forms of cell division have evolved. Both have
similar mechanisms, however they differ in their
overall outcome.
– Discuss the similarities and differences between the two
forms of cell division in terms of chromosome number and
arrangement.
– One form of cell division is essential to the diversity of
living things. Explain multiple ways that this process has
dramatically impacted the diversity of life.
Formative Assessment #2
• Mendel didn’t really understand
chromosomes…he just observed patterns.
Explain to Mendel:
– How his Law of Segregation leads to balance of
chromosomes and how this balance can be upset
– How his law of Independent Assortment allows so
many possibilities from just one mating!