<img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />
Skip Navigation
We experienced a service interruption from 9:00 AM to 10:00 AM. PT. We apologize for any inconvenience this may have caused. (Posted: Tuesday 02/21/2017)

Scientific Theories

Hypotheses that have stood up to repeated tests and are supported by data and evidence.

Atoms Practice
Estimated4 minsto complete
Practice Scientific Theories
This indicates how strong in your memory this concept is
Estimated4 minsto complete
Practice Now
Turn In
Living Fossils
Teacher Contributed

Why It Matters

But How Can A Fossil Be Alive?

Living fossils? But how can fossils be alive? I thought they were rocks? Excellet questions. Go here to read Brian Switek's strong opinion on this subject: http://www.wired.com/wiredscience/2012/08/a-rant-about-living-fossils/. In case you are wondering, the views expressed by Mr. Switek are far from uncommon in the scientific community.

Go here and you can see footage of a fish that was thought extinct for 66 million years before it was "discovered" in 1938 and has been called a "Living Fossil" perhaps more than any other species.

Go here to find out about efforts to protect another "living fossil"

Explore More

Use the below resources to answer the following questions

  1. Why is it significant that the two living species of Coelacanths (Latimeria chalumnae and Latimeria menadoensis) have never been found in the fossil record?
  2. How do Tuatara differ from lizards?
  3. How do lobed-finned fish differ from most fish we see today?
  4. Young Tuatara (Sphenodon punctatus)hunt during the day but the adults hunt at night? What theory have scientists put forth to explain this situation?
  5. What do scientists theorize is the purpose of the Tuatara’s third eye?
  6. What appears to be the main predator on Tuatara? Explain your answer.
  7. Recent work in molecular biology has shown that a relatively small percentage of the genes an animal carries control the animals physical form, yet for fossils all we have is physical form. Given this situation how valid do you think it is to call a living animal "unchanged" based on its similarities to a fossil organism? Explain your answer and be specific in your reasoning.
  8. You've developed a theory that the reason young Tuatara do not hunt at night is because their third eye isn't fully developed and this is needed for night hunting. Design an experiment to test this hypothesis, remember you want to control for as many variables as possible.

Resources Cited

    Notes/Highlights Having trouble? Report an issue.

    Color Highlighted Text Notes
    Please to create your own Highlights / Notes
    Show More

    Image Attributions

    Explore More

    Sign in to explore more, including practice questions and solutions for Scientific Investigation.
    Please wait...
    Please wait...
    Add Note
    Please to create your own Highlights / Notes