OwlSheets.com

Name Date

Puppy Checkups at the Animal Hospital

Use checkup records to sort out what genes and the environment do to a growing dog.

Answer Key

Two breeds

Read the passage and Table 1. Then answer questions 1–3.

A Week at Brightwater Animal Hospital

1Tavita Moreno, a sixth grader, spent a school vacation week shadowing her aunt, a veterinary technician at Brightwater Animal Hospital. The hospital, the people and the numbers here are made up, but they are based on real growth records for dogs. Each morning the vet, Dr. Ama Ferreira, showed Tavita how puppies are weighed before breakfast at every checkup and how their records are kept.

2All dogs belong to one species, but different breeds inherit different genes from their parents. Some of those genes affect how large a dog grows. Dr. Ferreira pulled the records of healthy beagle and Labrador puppies that were all fed the same kind of puppy food, the amount printed on the bag for their size. Adult beagles usually stand about 36 cm tall at the shoulder, and adult Labradors about 57 cm.

3Next she showed Tavita the records of four Labrador puppies from one litter. They had the same mother and father and were born on the same day. At 8 weeks old, each puppy went to a different home. Puppy food contains the protein, fats, vitamins and minerals a growing dog needs. Most puppies are also given medicine against roundworms, which live in the intestines, where a puppy's food is digested.

4Puppies A and B ate puppy food and got their worm medicine at 8 weeks. Puppy C's family missed the 8-week visit. At 12 weeks, Dr. Ferreira found many roundworms in Puppy C and treated them, and after that it ate the same puppy food as A and B. Puppy D got its worm medicine at 8 weeks, but its family fed it mostly rice, bread and leftovers. At the 16-week checkup, Dr. Ferreira explained what puppies need, and from then on Puppy D ate puppy food.

5On Friday, an owner asked whether feeding her young beagle extra food would make him grow as big as a Labrador. Dr. Ferreira answered with records of adult beagles, ages 1 to 3, from the hospital's files. Some of their owners fed the amount the vet recommended, and some fed about 30% more.

Table 1. Average Weight of Healthy Puppies at Checkups
Age (weeks)Beagles (kg)Labradors (kg)
82.56
165.515
24823
521030
1.

How many kilograms did the average Labrador gain from 8 weeks to 52 weeks? 24 kg

2.

At 52 weeks, the average Labrador weighed how many times as much as the average beagle? 3 times

3.
Use paragraphs 1 and 2. What best explains why the Labradors in Table 1 grew so much larger than the beagles?
  • A. The beagles ate a different kind of food, so their bodies grew more slowly.
  • B. The beagles were younger at each checkup, so they had less time to grow.
  • C. The Labradors were weighed after meals, which added kilograms each time.
  • D. The Labradors inherited genes from their parents for a larger body.

Four puppies from one litter

Use paragraphs 3 and 4 and Table 2 to answer questions 4–8.

Table 2. Labrador Littermates' Weights (kg)
PuppyWhat happened8 weeks12 weeks16 weeks24 weeks
APuppy food; worm medicine at 8 wk610.51523
BPuppy food; worm medicine at 8 wk6.210.815.423.6
CRoundworms treated at 12 wk5.67.512.522
DLeftovers until 16 wk, then puppy food691121
4.

At 12 weeks, how many kilograms lighter was Puppy C than Puppy A? 3 kg

5.
Why does comparing puppies from one litter help Dr. Ferreira see the effects of the environment on growth?
  • A. Littermates share parents, so their genes are more alike than unrelated puppies' genes.
  • B. Littermates all ate meals from the hospital, so their food came from one place.
  • C. Littermates all got worm medicine at 8 weeks, so their health stayed the same.
  • D. Littermates all lived in one home, so they ate the same food every day.
6.
Puppy C grew slowly from 8 to 12 weeks. Which explanation fits paragraphs 3 and 4 best?
  • A. Puppy C inherited genes for a small body, unlike its brothers and sisters.
  • B. The roundworms lived where food is digested, so less was left for growing.
  • C. Puppy C was the youngest puppy in the litter, so it had fewer weeks to grow.
  • D. The roundworms changed Puppy C's genes, so its body was set to stay small.
7.

From 12 weeks to 16 weeks, Puppy C gained 5 kg and Puppy A gained 4.5 kg.

8.
Which result is the best evidence that Puppy D grew slowly because of its diet and not because of its genes?
  • A. Puppy D is a Labrador with the same parents as Puppy A.
  • B. Puppy D weighed less than Puppy A at the 16-week checkup.
  • C. After it switched to puppy food, Puppy D gained 10 kg in 8 weeks.
  • D. Puppy D weighed 6.0 kg at 8 weeks, the same as Puppy A.

Extra food for a beagle?

Use paragraph 5 and Table 3 to answer questions 9–13.

Table 3. Adult Beagles in the Hospital's Records (averages)
Daily foodDogsShoulder height (cm)Weight (kg)Body shape
Amount the vet advised253610Ribs easy to feel
About 30% more153613Thick waist; ribs hard to feel
9.

On average, how many kilograms heavier were the beagles fed about 30% more? 3 kg

10.
Which answer to the owner's question in paragraph 5 does Table 3 support best?
  • A. Extra food would change little, since both groups of beagles were the same.
  • B. Extra food would likely add fat, but his height would stay near a beagle's.
  • C. Extra food would change his genes, so his puppies would be born larger.
  • D. Extra food would make him taller, since the well-fed beagles were the largest.
11.
Sort each difference from the hospital records by what most likely caused it.
Adult Labradors stand about 57 cm at the shoulder, and adult beagles about 36 cm.Puppy C weighed 2.5 kg less than Puppy A at 16 weeks.Beagles fed about 30% more had thicker waists than other beagles.At every checkup, the average beagle weighed less than the average Labrador.Puppy D weighed 4 kg less than Puppy A at 16 weeks.
Mostly genesMostly the environment
Adult Labradors stand about 57 cm at the shoulder, and adult beagles about 36 cm.
At every checkup, the average beagle weighed less than the average Labrador.
Puppy C weighed 2.5 kg less than Puppy A at 16 weeks.
Beagles fed about 30% more had thicker waists than other beagles.
Puppy D weighed 4 kg less than Puppy A at 16 weeks.
12.
Suppose a Labrador puppy and a beagle puppy both had roundworms from 8 to 12 weeks, were treated at 12 weeks and then ate puppy food. Which prediction for their weights at 52 weeks fits Tables 1 and 2 best?
  • A. The Labrador would likely be much heavier, with each dog near its breed's weight.
  • B. Both would stay far below their breeds' weights, since worms change size genes.
  • C. The beagle would catch up to the Labrador, since both got the same treatment.
  • D. Both would weigh about 20 kg, since the worms slowed them by the same amount.
13.
At the 12-week checkup, Puppy C's owner said, "My puppy is the smallest of the litter, so he must have genes for being small." Do the records support this? Write a claim, give evidence from Table 2 and paragraph 4, and explain your reasoning about genetic and environmental factors.

The records do not support this. Puppy C has the same parents as Puppies A and B, so its genes for size are likely similar to theirs. At 12 weeks it weighed 7.5 kg, while A weighed 10.5 kg, but it had many roundworms living where its food is digested, so less food was left for growing. After the worms were treated at 12 weeks, Puppy C gained 5 kg in four weeks, more than Puppy A's 4.5 kg, and by 24 weeks it weighed 22.0 kg, close to A's 23.0 kg. Its slow growth came mainly from an environmental factor, the worms, not from genes for a small body.