How are traits passed down from one generation to the next? LAB: Analyzing Inheritance in Fast Plants

Why do these plants grow faster than other plants?

What will our seeds look like when they grow? Fast Plant Development Time Lapse

How did the parent-plants create the next generation? Pollinating and Harvesting Fast Plants

Wisconsin Fast Plants Non-Purple Stem Purple Stem

Second Generation F 2 First Generation F 1 Parent Generation (P 2 ) PURPLE Parent Generation (P 1 ) NON-PURPLE Parent 1 Seeds (P 1 ) Parent 2 Seeds (P 2 ) The seeds from the pollinated F 1 Plants are used to grow the F 2 Generation The seeds from the pollinated Non-Purple Plants are used to grow the F 1 Generation Seeds Grow into F 1 Seeds Grow into F 2 POLLINATION X Fast Plant Generations POLLINATION

PLANTING PROCEDURES ① Measure 2 cm from the bottom of each filter paper and draw a line. 2 cm Table Name Class Name Generation Name ② Write the name of the generation (P 1, P 2, F 1, F 2 ) and the names of your table/class.

PLANTING PROCEDURES ③ Put the filter paper inside the petri dishes. 2 cm Table Name Class Name Generation Name ④ Fill the pipet with water; slowly moisten the filter paper with drops of H 2 O. ⑤ Send 1 person to Ms. B collect the seeds for each generation.

PLANTING PROCEDURES ⑥ Evenly spread out the seeds on the filter paper. Place them ABOVE the line. 2 cm Table Name Class Name Generation Name ⑦ Wait for 1 minute then cover the petri dishes. ⑧ Bring the petri dishes to Ms. B to place under the lamp.

Results: P Generation

Results: F 1 Generation

Results: F 2 Generation

The A, B, Peas… of Life!! How the study of pea plants changed the way we think about life. (Genetics Week 1) How the study of pea plants changed the way we think about life. (Genetics Week 1)

I Can #10 I CAN describe the results of Mendel's crosses and explain the significance of Mendel's findings for modern genetics.

Have you ever wondered why some family members look very similar while others look very different?

These are pictures of Peter, Lois, and Chris from Family Guy. Which character traits does Chris have in common with his Dad or his Mom? DAD: Peter MOM: Lois SON (offspring): Chris

Heredity and Traits Traits are different forms of a characteristic. Heredity is the passing of traits from parent to offspring (children). Traits are different forms of a characteristic. Heredity is the passing of traits from parent to offspring (children). Detached Earlobe Attached Earlobe

More on Heredity… Only certain traits can be passed from parent to offspring… For example, you might inherit your Dad’s hair color but you wouldn’t inherit the scar on his chin leftover from a painful football practice… Only certain traits can be passed from parent to offspring… For example, you might inherit your Dad’s hair color but you wouldn’t inherit the scar on his chin leftover from a painful football practice…

Purebred A true-breeding or a purebred organism is the offspring of many generations that have the same characteristics. For example, purebred purple pea plants always come from purple parent plants. A true-breeding or a purebred organism is the offspring of many generations that have the same characteristics. For example, purebred purple pea plants always come from purple parent plants.

Gregor Mendel and Genetics Gregor Mendel (a 19th century monk), was the first person to study genetics (the scientific study of heredity).

Mendel’s Question Why are pea plant’s traits sometimes similar to their parents and sometimes very different?

Mendel’s Hypothesis Mendel hypothesized that something was being passed from parent to offspring to control the passing of traits--but how? And was there a pattern? Hmmm…the passing of traits must be controlled by something…right?

Mendel’s Experiment Mendel decided to “cross” two plants with different traits to see what traits the offspring would have. In his first experiment he “crossed” a tall plant with a short plant. Mendel decided to “cross” two plants with different traits to see what traits the offspring would have. In his first experiment he “crossed” a tall plant with a short plant.

Mendel’s Experiment Mendel called this first generation of parent plants the parental generation or P generation The tall and short pea plants he used were both purebred. Mendel used a paint brush to “cross-pollinate” the two plants. Mendel called this first generation of parent plants the parental generation or P generation The tall and short pea plants he used were both purebred. Mendel used a paint brush to “cross-pollinate” the two plants. ?

Mendel’s Data In the second generation of pea plants, Mendel saw that all of the offspring were tall. He decided to cross this second generation (called F 1 Generation) with each other to see what would happen. In the second generation of pea plants, Mendel saw that all of the offspring were tall. He decided to cross this second generation (called F 1 Generation) with each other to see what would happen. ?

Mendel’s Data But the next generation (F 2 Generation) was more surprising! He had all tall plants except for one small plant! But the next generation (F 2 Generation) was more surprising! He had all tall plants except for one small plant! WAIT! So 2 tall plants produced a SHORT plant?!

Mendel Experiments Again (and again….) Mendel was so confused by the sudden re- appearance of the “short” trait, that he decided to do more experiments like this one but with different traits.

Mendel’s Next Experiment Violet vs. White Violet vs. White

Mendel’s Data In all of Mendel’s crosses, only one form of the trait showed in the F 1 Generation. However, in the F 2 Generation, the “lost” form of the trait always appeared in 1/4 of the plants. In all of Mendel’s crosses, only one form of the trait showed in the F 1 Generation. However, in the F 2 Generation, the “lost” form of the trait always appeared in 1/4 of the plants.

Mendel’s Conclusions The “factors” that control each trait exist in pairs. The female parent contributes one factor, while the male parent contributes another factor. One factor in a pair can “hide” the other factor. (The “tall factor” hides the “short factor”. The “factors” that control each trait exist in pairs. The female parent contributes one factor, while the male parent contributes another factor. One factor in a pair can “hide” the other factor. (The “tall factor” hides the “short factor”.

Summarizing Mendel’s Experiments  Mendel wanted to know how it was possible for a trait like white pea plant color to disappear in one generation and then reappear in the next.  His conclusion: the trait is always there--its just hidden by another trait!!  Mendel wanted to know how it was possible for a trait like white pea plant color to disappear in one generation and then reappear in the next.  His conclusion: the trait is always there--its just hidden by another trait!!

Dominant and Recessive Alleles  Mendel came up with the terms DOMINANT and RECESSIVE alleles to describe how some traits could be “hidden” or “masked” by other traits.