mendel

Instructions

• Come in and have a seat quickly and quietly

• Hook:

What is the difference between a trait and an allele? Give examples of two traits and their possible alleles.

Gregor Mendel (p. 121)• “Father of Genetics”

• Born in Austria in 1822, left home to join a monastery at 21.

• Life Goal: To become a teacher…

• …Mendel was a horrible test taker and failed his final exam…so he returned to the monastery

Gregor Mendel by Kaptain Kobold

Mmmm…Peas…

• Monastery Gardner

• Saw Differences in Peas

• What were his questions??

Sea of Peas by pwilley

To Build a Better Pea…

• Goal: Find a way to grow better pea plants

• Saw different characteristics

• Which are best?

Pea Flowers, Part II by tstadler

Flower ReproductionPollen produced by Anther (male) transferred to Stigma (female)

Leads to seed formation in Ovule

Self-pollination

• Pea plants are able to self-pollinate as well as cross-pollinate

X

YIELDS

This is known as “true-breeding”

Mendel’s Experiment

• Mendel wondered what would happen if he crossed true-breeding purple and white plants

X

WHAT HAPPENED!!!???

Mendel’s Second Experiment

• Mendel took some of the new generation of peas and crossed them

X

HUH????

How did this happen?

• With a partner nearby…– Discuss what Mendel’s experiments showed– Try and determine the reason Mendel got the

results he did

Dominant vs. Recessive Alleles

• Mendel had discovered the basis of dominant and recessive alleles

• Dominant alleles are ones that are expressed (shown) if they are present

• Recessive alleles are hidden (recede) by dominant if only one copy is present

Second Generation (p. 120)Characteristic Dominant Recessive Ratio

Flower Color 705 Purple 224 White 3.15:1

Seed Color 6002 YELLOW

2001 GREEN

Seed Shape 5474 round 1850 wrinkled

Pod Color 428 green 152 yellow

Pod Shape 882 smooth 299 bumpy

Plant Height 787 TALL 277 short