Blended and both-showing traits
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
A snapdragon cross (model data)
offspring counted flower color 60 all pink Ari reads a snapdragon cross card. Every offspring has pink flowers. Which parents could these be?
- Two pink parents (RW × RW)
- One pink parent and one white parent (RW × WW)
- One red parent and one pink parent (RR × RW)
- One red parent and one white parent (RR × WW)
Bo reads a snapdragon cross card. The offspring are about half pink and half white. Which parents could these be?
- Two pink parents (RW × RW)
- A pink parent and a white parent (RW × WW)
- One red parent and one white parent (RR × WW)
- One red parent and one pink parent (RR × RW)
A cattle cross (model data)
coat calves counted red 24 roan 51 white 25 Esme reads a model cattle cross card. The calves are red, roan and white. Which parents could these be?
- One red parent and one white parent (RR × WW)
- Two roan parents (RW × RW)
- One roan parent and one white parent (RW × WW)
- One roan parent and one red parent (RW × RR)
Kira grows two seedlings from the cross of two pink snapdragons. What is the chance that both have white flowers?
- 1 in 16, since 1/4 × 1/4
- 1 in 4, the chance for one seedling
- 0, since the white allele is blended away in pink plants
- 1 in 2, since 1/4 + 1/4
Luz follows a model cross of a roan parent and a red parent. What is the chance that three calves in a row are roan?
- 1 in 8, since 1/2 × 1/2 × 1/2
- 1 in 6, since 1/2 ÷ 3
- 1 in 2, the chance for one calf
- 1 in 4, since 1/2 × 1/2
Notebook
Notes on two pink snapdragons (classmate's notebook), 4 lines. Columns: line, entry. Line 1: Each pink parent is RW and passes on one of its two alleles, chosen at random. Line 2: So the four boxes are RR, RW, RW and WW. Line 3: The genotypes are in the ratio 1 : 2 : 1. Line 4: The flower colors are in the ratio 3 : 1.
Milo reads a classmate's notebook about two pink snapdragons. Which line has the mistake?
- Line 3: the genotypes should be in the ratio 3 : 1
- Line 1: a pink parent should pass on both of its alleles
- Line 4: the colors are 1 red : 2 pink : 1 white
- Line 2: the two RW boxes should be counted as one box
Notebook
Notes on a roan calf (classmate's notebook), 4 lines. Columns: line, entry. Line 1: A roan calf has one red allele and one white allele (RW). Line 2: Both alleles show, so red hairs and white hairs grow side by side. Line 3: The red and white hairs blend into one pink color on every hair. Line 4: Two roan parents can give red, roan and white calves.
Noah reads a classmate's notebook about a roan calf in a model cross. Which line has the mistake?
- Line 3: each hair stays red or white and does not blend
- Line 1: a roan calf should show red hairs alone, since R is dominant
- Line 4: two roan parents give roan calves, not red or white
- Line 2: roan is incomplete dominance, with one in-between color
Notebook
Notes on a pink × pink cross (classmate's notebook), 4 lines. Columns: line, entry. Line 1: The expected ratio is 1 red : 2 pink : 1 white. Line 2: Of 80 seedlings, the expected counts are 20 red, 40 pink and 20 white. Line 3: The class counted 23 red, 38 pink and 19 white. Line 4: The counts are not 20, 40 and 20, so the cross does not follow the ratio.
Pia reads a classmate's notebook about a pink × pink cross. Which line has the mistake?
- Line 2: 80 seedlings should give counts that add to 100
- Line 1: the expected ratio should be 3 : 1
- Line 4: counts land near the expected counts, not on them
- Line 3: the class should have counted exactly 20, 40 and 20
Class counts for a pink × pink cross (model data)
flower color counted expected red 24 25 pink 52 50 white 24 25 Tala says the cross failed because the counts are not exactly the expected counts. Do you agree?
- Yes, because the cross should give 75 colored and 25 white
- No, because real counts land near the ratio, not on it
- Yes, because counts must match the ratio exactly
- No, because 52 pink shows pink is dominant over red and white
Table
Two patterns (model), 2 rows. Columns: pattern, what the heterozygote shows. Row 1: incomplete dominance, one in-between look, such as pink snapdragons. Row 2: codominance, both parent looks side by side, such as roan red and white hairs.
Zee says roan is just incomplete dominance, since the roan calf looks in between red and white. Do you agree?
- No, because roan parents give roan calves, not red or white
- No, because roan shows both looks, not one in-between look
- No, because roan is complete dominance, with red hiding white
- Yes, because both patterns give one mixed color