What evidence do you have to support which species first separated from the common ancestor?
CFS:
student describes the relationship between anatomical similarities and differences in animal species
student describes the environmental difference between animal species with a common ancestor based on body structures
student describes the chronological changes between animal species with a common ancestor based on body structures
Question 1
1.
Question 2
2.
Question 3
3.
What do you think the common adaptive trait is for the Echidna, Natterjack Toad, and Blue tang?
Ribs
Neck Bones
Spines
Smooth Skin
Scales
This echidna, this natterjack toad, and this blue tang have similarities and differences in their body structures. What does the information about these structures tell you about the ancestors of these species?
We cannot make observations of ancestor populations from the past. It is impossible to explain ancestors with only the information about the body structures of different species.
None share an ancestor population because different species cannot share an ancestor population. It is a coincidence that these species have some of the same body structures.
All three species share an ancestor population, but echidnas and natterjack toads share a more recent ancestor population. This is why they share the neck-bone structure.
Echidnas and natterjack toads share an ancestor population, but they must not share an ancestor with the blue tang because blue tangs have no neck bones.
Which species, Echidna, Natterjack Toad, or Blue tang, do you think was the first to separate from the common ancestor?
