The following 9 Anchor Papers represent a range of score points and are used in conjunction with the rubric to assess student responses.

Score for Anchor Paper #1: Rubric Score 1

Annotation: This response demonstrates some understanding of the question. The first-generation Punnett square is correct. The remainder of the response is either a restatement of the prompt (9 out of 10) or incorrect (weak trat; comes out of no were).

Score for Anchor Paper #2: Rubric Score 1

Annotation: This response demonstrates some understanding of the question. The first-generation Punnett square is incorrect, but the second is correct. The student correctly states the probability of a short-tailed puppy in the second generation (75%), but the explanation for having a long-tailed puppy is unclear (heterozygous giving it a 50% chance of having a long tail dog).

Score for Anchor Paper #3: Rubric Score 2

Annotation: This response shows a basic understanding of the question. Both Punnett squares are correct. The student uses adequate details to explain how a long-tailed dog suddenly appeared in the second generation litter (both parents had a long tail gene in them; both parents were heterozygous). The student's discussion of ratios concerns the actual litter (all puppies are short-tailed except one; 1 out of 10) instead of the theoretical probabilities from the Punnett square.

Score for Anchor Paper #4: Rubric Score 2

Annotation: This response demonstrates a basic understanding of the question. Both Punnett squares are correct and the genotypes of the parents are identified (TT & Tt). The genotypic and phenotypic ratios are not provided, however adequate support is given for the explanation of how a long-tailed puppy could appear (both of his/her parents were most likely Heterzygous).

Score for Anchor Paper #5: Rubric Score 2

Annotation: This response demonstrates a basic understanding of the question. The parents' genotypes for both generations (TT, Tt; Tt, Tt) are identified, and both Punnett squares are correct. The explanation of how a long-tailed puppy could have two short-tailed parents is brief but accurate (only when both parents are heterozygous (allels are Tt, Tt)). Supporting details, found mostly in the correct Punnett square for the second generation, are adequate, although the student lists the actual ratios of puppies in the litters (12:0; 9:1) instead of the correct phenotypic ratios determined from the Punnett square, and the genotypic ratios are omitted altogether.

Score for Anchor Paper #6: Rubric Score 3

Annotation: This response shows a good understanding of the question. The student provides generally complete details to explain each part of the question. The student identifies the genotype of the parents (1^st parent was homozygous dominant…TT; the second parent was heterozygous….Tt) and correctly completes both Punnett squares. The genotypic and phenotypic ratios are reversed and not labeled (In the first generation the genotypic ratio was 4. The phenotypic was 2-2). The student explains how a long-tailed puppy could appear (both parents were carriers of the recessive gene for long tails) and additionally supports this statement by circling the genotype in the Punnett square. Overall the supporting details are generally complete.

Score for Anchor Paper #7: Rubric Score 3

Annotation: This response demonstrates a good understanding of the question. The genotypes of the parents are not explicitly identified, but the correct Punnett squares make it clear that the student knows what they are. Genotypic ratios (1:1; 1:2:1) are correct numerically though unlabeled. The phenotypic ratio for the first generation is incorrect (1:1), but that for the second is numerically accurate (3:1). Despite some incorrect use of terminology (homozygous long tailed offspring), which combines the genotype and phenotype, supporting details for the conclusion, including the Punnett square (both parents are heterozygous; pass down a little t), are generally complete.

Score for Anchor Paper #8: Rubric Score 4

Annotation: This response demonstrates a full and complete understanding of the question. Phenotypic ratios are fully specified for both generations (4 short-tail: 0 long-tail; 3 short-tail: 1 long-tail), as are the genotypic ratios (2 TT: 2 Tt: 0 tt; 1 TT: 2 Tt: 1 tt). The Punnett squares are correct. The conclusion includes all pertinent details (a puppy recieved a recessive allele from both parents), and scientific terminology (carried but did not express) enhances the response. The markings on the Punnett squares help to integrate all aspects of the response (one taken from the 1^st generation litter).

Score for Anchor Paper #9: Rubric Score 4

Annotation: This response shows a full and complete understanding. Both Punnett squares are correct. The genotypic ratios are correct and fully labeled (25% homozygous dominant, 25% homozygous recessive and 50% heterozygous), demonstrating both inclusion of all pertinent details and the accurate use of scientific terminology. Elsewhere, terminology also enhances the response (carry the gene). The student integrates all aspects of the question with strong supporting details and synthesis (must have both carried the recessive trait; Because short tails are a dominant trait, a heterozygous dog will have a short tail), fully explaining the appearance of a long-tailed puppy (because the two recessive genes merged together).

Additional Scored Student Responses