1. Embryo Dice Questions

2. What similarities do the drawings have? Similarities include similar eyes, tails and visible spinal cords. Notice that each embryo develops a tail, buds that become limbs and pharyngeal pouches (which house the gills of fish and amphibians).

3. What are the differences? Differences should include the size and shape of the embryos.

4. What trends do you see as you go from stage to stage? Although vertebrate bones are homologous, limbs develop differently in each group. The tail remains in most adult vertebrates. Although the coccyx (tail bone) serves as a point of attachment for certain muscles, this small internal tail does not resemble the long external tail of most other vertebrates. In humans the tail and pharyngeal pouches are relics (forms from the past) that disappear before birth.

5. Which Stage 3 embryos were easiest to match to the correct animal? Opinions will vary but often times it is: – the fish because of the body shape – the pig because of the snout – the chicken because of the beak

6. Which stage of embryos (Stage 1,2 or 3) were the most difficult to match to the correct animal? Most often it is the Stage 1 embryos that are the most difficult to match to the correct animal. There are a lot of similarities at this stage and the distinguishing features have not developed yet.

7. How does looking at the embryos help you to see if there are relationships among organisms that are not evident in the fully formed anatomy? There are similarities in the stage 1 (like the curly tails, the gills, or the vertebraes) that are evident early on but are not seen in the actual animal.

8. Order of Embryos from earliest to latest in development. Fish = 8,1,14 Chicken = 2,7,9 Human = 4,11,5 Calf = 10,15,12 Pig = 3,6,13