Vascular plants appeared about 450 million year ago. Vascular plants have existed on earth for ______.

Question

A.  10% of its history
B.  20% of its history
C.  50% of its history
D.  75% of its history
E.  90% of its history

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 age of the earth?
 
Choose Answer
· Given what you now know, what information and/or problem solving approach 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

A.  10% of its history

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses the age of the earth.
· What type of thinking is required?
        o This question is asking you to take what you already know and apply it to this unfamiliar situation.

  Gather Content
· What do you already know about the age of the earth?
        o The planet first formed and began to cool 4500 million years ago, or 4.5 billion years ago.
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Since vascular plants are 450 million years old, they have only been around for 10% of the earth’s history. Surprising, isn’t it?
        o Of course, multicellular life has been around for less than 1 billion years, so vascular plants have been present during much of the time that multicellular organisms have been.
 
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?
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you remember that the earth first formed 4500 MYA?
        o Did you realize that that means vascular plants have only been around for 10% of the history of the planet?