Choose the evidence supporting that snakes evolved from legged lizards. Check all that apply.

Question

_____  Snakes have pelvic bones.
_____  The oldest snake-like fossils have leg bones.
_____  Transitional fossils show sections of the snake backbone evolving into legs.
_____  Snake embryos temporarily develop limb buds which are reabsorbed before birth.

Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?
 
Gather Content
What do you already know about the evidence for evolution? What other information is related to the question?

  Choose Answer
Given what you now know, what information is most likely to produce the correct answer?

  Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

__X__  Snakes have pelvic bones.
__X__  The oldest snake-like fossils have leg bones.
_____  Transitional fossils show sections of the snake backbone evolving into legs.
__X__  Snake embryos temporarily develop limb buds which are reabsorbed before birth.

Clarify Question
What is the key concept addressed by the question?
        · The question stem is asking you to select which pieces of evidence would support the evolution of snakes from a legged lizard ancestor.
What type of thinking is required?
        · You are being asked to take what you already know and use, or apply, it to the evolution of snakes.
 
Gather Content
What do you already know about the evidence for evolution? What other information is related to the question?
        · Anatomical evidence for evolution can help determine the relatedness between divergent species. Embryonic development shows similarity in developmental patterns among species whose adult phenotypes are very different. Species that have lost a feature that was present in an ancestral form often develop and then lose that feature during embryological development.

  Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · If snakes have no hind legs, then why would a pelvic bone be present in snakes? Why would embryonic snakes form limb buds?

  Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · Answering this question correctly depended on your ability to use the anatomical evidence for evolution in a new situation¼ If you got an incorrect answer, did you remember that the anatomical evidence for evolution includes vestigial structures and embryonic development?