Mendel and his Peas

Why Don’t You Look Like a Rhinoceros? Heredity – passing of traits from parent to offspring

Who was Gregor Mendel? Born in 1822 Austrian monk Studied how traits are passed from parent to offspring in the monastery garden http://science.discovery.com/videos/100-greatest-discoveries-shorts-genetics.html

Unraveling the Mystery Mendel studied pea plants WHY? Easy to grow Have many traits Pea plants can self-pollinate – this means the plant has both MALE and FEMALE reproductive parts

Self Pollinating During pollination, pollen from the anthers (male) is transferred to the stigma (female)

How many different “forms” of eye color exist? Peas Be My Ponder Mendel chose to study only one characteristic at a time such as - height OR pea color Tall/Short Green/Yellow And he chose plants that had two forms for each of the characteristics studied How many different “forms” of eye color exist?

Pea Plant Traits Characteristics: Use Figure 4 (pg 110) in your textbook to list the 7 characteristics of pea plants and their two forms – think, pair, share!

Pea Traits

True Breeding Plants A true bred parent will ALWAYS produce offspring with the same trait Examples … A true bred purple flower will produce ? flowers A true bred yellow seed will produce ? seeds

MENDEL’s 1st Experiment Mendel crossed two true bred plants with different forms of the same trait Wrinkled seed plant X Round seed plant

MEDEL’S 1ST EXPERIMENT When Mendel crossed round seed plants X wrinkled seed plants, the new plant had ALL ROUND seeds The offspring from this cross are known as the First generation or F1

MENDEL’S 1ST EXPERIMENT For each cross, one trait always appeared and the other seemed to vanish in F1 Dominant – trait that appears/stronger Recessive – trait that vanishes/hidden What is the dominant trait? What is the recessive trait?

MENDEL’S 2nd EXPERIMENT Mendel allowed first generation (F1) from each cross to self-pollinate  Round seeds X Round seeds When the F1 generation self-pollinated, the wrinkled (recessive) reappeared in the Second generation (F2)!

MENDEL’S RESULTS MENDEL’S RESULTS: In the 2ndgeneration, the RECESSIVE trait showed up again but NOT as often as the DOMINANT Can you determine the ratio of D to R? __:__

MENDEL’S EXPERIMENTS Use Figure 6 (p. 109) to explain Mendel’s First and Second Experiments:

MENDEL’S EXPERIMENTS

http://www.videosurf.com/video/gregor-mendel-rap-54017176