Hand in W'S' 8'1 before the bell rings please

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Class Topics
Title Biology 1/26/07
Objectives

• To assess learning about genetic variation due to
  meiosis and about gametogenesis.

• Hand in W.S. 8.1 before the bell rings please
• Review Chapter 7 Test
• Chapter 8 Mendelian Genetics
• Terms
• Mendels research
• Mendels laws
• "It has become fashionable in science education
  to mold K-12 students around an idee fixe of a
  modern scientist formulating hypotheses,
  observing measuring, and discovering through
  hands-on investigations. What has been left
  unsaid is that real scientists don't actually
  spend very much of their day 'observing' and
  'measuring.' They read! Reading for understanding
  of content is the core process skill of science,
  and there is no substitute for practice at an
  early age. ... -- Dr. Stan Metzenberg, "Reading
  The Most Important Science Process Skill"

Wednesday, November 18, 2009 629 PM
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Class Assignments
By When
What

• Read 161-165 1/26/07
• W.S. 8.1 (DR/Quiz) 1/26/07
• Read 166-170 1/30/07
• W.S. The Puzzle of Heredity 1/30/07
• Due this class period
• Due next class period
• Due in the future

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Grade Sheet
2A p. 157 (5 pts.)
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Chapter 7 Test Review

• Absolutely no talking
• You have 7 minutes to review your exam do not
  write anything on the test
• You will get your test back next class period and
  be given 20 minutes to adjust any answers.
• I suggest you make notes
• of items to study
• of questions to ask

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Mendels Breeding experiments8.1

• Gregor Johann Mendels history
• Father of genetics
• Bred garden peas (Pisum sativum)
• 1st to develop rules to predict patterns in
  inheritance of traits
• Quantitative Data!!!!
• Used very large samples
• Kept careful records
• Minimized errors (took time and stayed organized)

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Key Terms I7.1

• Heredity
• Passing traits from parents to offspring
• Genetics
• Branch of biology that studies heredity
• Gene
• Unit of DNA that controls traits
• Cross
• Mating or breeding of two individuals

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Why peas?8.1

• Several traits take clearly different forms
• Ex. Yellow or green seeds
• Male and female parts of peas are enclosed within
  the same flower
• Mating can be controlled as either
• Self fertilization (self-pollination)
• Cross-pollination
• Mendel removed the stamens (male) from the flower
  of on plant and dusted the pistil (female) of
  another
• Peas are small, grows quickly, and produces many
  offspring
• Not to mention that the offspring can be used as
  food!!

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From http//www.people.virginia.edu/rjh9u/monot
raits.html
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• Peas have 14 chromosomes (? Pairs) and each gene
  was on a different chromosome

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Key Terms II

• Monohybrid cross
• A cross that involves one pair of contrasting
  traits
• True breeding (pure)
• All offspring display the same form of the trait
• P generation
• 1st two individuals (mated or bred)
• F1 generation
• Offspring of P generation (F means filial)
• F2 generation
• Offspring of self-pollinated F1 generation

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Example of a classic Mendels cross

• P generation
• Tall crossed with dwarf (both purebreeding)
• F1 generation
• All tall
• Self-pollinate a single example of F1
• F2 generation
• 787 tall, 277 dwarf
• 2.84 1 ratio
• Close to a 31 ratio

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Math Labp. 165

• Calculating Mendels ratios
• Copy the table
• Calculate the ratio
• State the ratio in words and then as a fraction
• Answer the final question

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Mendels Theory

• Historical perspective
• Heredity was thought of as a blending of the two
  parents
• Mendel determined that there were two separate
  heritable factors for each trait
• Factors are called alleles (book says genes)

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Mendels hypothesis

• 1. For each inherited trait, an individual has
  two copies of the gene one from each parent.
• 2. There are different versions of genes.
• Alleles
• Receive one from each parent

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Mendels hypothesis

• 3. Dominant allele
• Can mask the presence of another allele
• Expressed whenever present
• Represented by a capital letter
• recessive allele
• Can be masked by the presence of a dominant
  allele
• Only expressed when contrasting allele is not
  present
• Represented by a lowercase letter (same letter as
  dominant)