Clues that living things share ancestors
Grade 7 Science Worksheet - Challenge Me
Circle the best answer.
Ari reads the whale chart. Which claim uses both the fossil rows and the flipper row?
- Fossil limbs shrink in order, and a living land animal became a whale
- Fossil limbs grow in order, and the flipper keeps the leg bones
- Fossil limbs shrink in order, and the flipper has new bones
- Fossil limbs shrink in order, and the flipper keeps the leg bones
Bo says a flipper cannot be related to a leg, since one swims and one walks. What does the chart show?
Use the picture in question 1.
- Wrong: fossils go from legs to paddles, and the flipper keeps leg bones
- Wrong: flippers and legs look alike, so the animals must be close relatives
- Right: fossils cannot show how limbs change
- Right: a different job means different bones
Esme asks why a swimming flipper and a walking cat leg share bones. Which reason fits the chart?
Use the picture in question 1.
- Both limbs move the animal about, so the two limbs must have the same bones in them
- Both limbs look alike, so the animals are close relatives
- A living cat turned into a whale, so they share bones
- Both came from a shared ancestor's limb, as the fossils show limbs changing
The bird wing and butterfly wing both fly, yet Jun says they are not close relatives. Which explanation fits the chart?
- Same job, so the animals share a recent ancestor
- Same job, different build, so the wings evolved separately
- Different build, so the wings must do different jobs
- A living butterfly came from a living bird, since both of them fly
Kira reads the wing chart. Which two animals does it link most closely, and why?
Use the picture in question 4.
- Bat and butterfly, since both wings work in flight
- Bird and bat, since their wings share the same forelimb bones
- Bird, bat and butterfly equally, since each wing has the same job
- Bird and butterfly, since both wings are used for flying
Luz reads two results on the wing chart, the job and the bones. Which is better evidence of a shared ancestor?
Use the picture in question 4.
- The bones, since matching parts come from a shared ancestor
- Neither, since a chart cannot show ancestry
- The job, since animals that fly share a recent common ancestor
- The job, since bones follow the job
Read this first
Use the table
Three stretches of DNA that chicken and turkey both have (real data: Dalloul et al. 2010, PLoS Biology; percents are about) (real data: Dalloul et al. 2010, PLoS Biology). Comparison chart.
DNA stretch Length (letters) Chicken and turkey match (percent) CR1_B 2,000 91 Birddawg_I 3,600 89 Galluhop 1,200 91 Milo says: Chicken and turkey match in 91 percent of their body traits. What is the flaw?
- The flaw is that 91 percent is too low to show any link
- The 91 percent counts matching DNA letters in one stretch, not body traits
- The flaw is that chicken and turkey are the same animal
- No flaw, since a high DNA percent means most traits match
“layers never moved” Pia says: The moth wing print is in Layer 1, the top layer, so it is the oldest fossil. What is the flaw?
- The flaw is that the crab shell should be the youngest
- The flaw is that fossils in one quarry share an age
- The top layer is the youngest, so the moth wing print is the youngest
- No flaw, since layers on top formed first
Ren reads the embryo chart. Which claim and reason fit best?
- Unrelated animals, since the adults differ in gills
- A living shark became a rabbit, since the early parts match
- The same kind of animal as adults, since the early embryos look much alike
- A shared ancestor, since all three early embryos have the same parts
Zee reads the DNA chart. Which claim and reason fit best?
- Kind 6 is closer to Kind 5, since more DNA letters match
- Neither kind is closer to Kind 5, since a percent says nothing about relatives
- Kind 6 shares 97 percent of body traits with Kind 5, since the percent counts traits
- Kind 7 is closer to Kind 5, since fewer DNA letters match
