What came first Basking Sharks or Megalodon? Question for Zoodiver!

[Pazzoman]

Hey Everyone,

I usually hate when some one posts something about homework on here but Im honestly stuck. Im doing the evolution of sharks and sadly since I wasn't clear on a specific species I have to do "sharks" not just one specie like the great white....so I pretty much have to cover a different groups of sharks.

Using this link: https://www.sharksavers.org/en/education/biology/450-million-years-of-sharks1/

It says that filter feeding sharks cam before Megalodon...since I have to also write why may have the animal change its lifestyle to adapt I was gonna write that another factor why sharks suddenly go large like Megalodon was that their was abundant populations of whales as well as the large filter feeding basking sharks..however Im unsure.

I know its not really important just would like to incorporate the the filter feeders as well.

Sorry for all the info

 

[Zoodiver]

Food supply and water conditions would be the best guess as to why large predatory sharks as well as large filter feeding sharks both came about.

As to age - there is a LOT of friction between researchers, depending on which material you are reading. Some will use terms like 'billions of years ago', while others will say to due pressure of the water depth the dating methods aren't accurate. It's very clear that the Earth was all/mostly water when some of these ancient monsters were cruising around. That is proven by the fact that shark teeth and fossils are being found in the Rocky Mountains as well as all over Asia. That tells use the depth was tremendous during that time frame. Without known the depth (and then using math to calculate the pressues), any dating of those types of artifacts is just a guess (at best).

My personal thought is that we don't know enough about the conditions during that time frame to use our current methods of dating. We can say what existed with what, but not a definitive time frame.

 

[Cu455]

I took a online course through the museum of natural history on sharks and rays. It was part of their seminar online program. There was a unit on shark evolution which had a ton of articles. You should see if you can access the information. If you can't get it I will try to get my log in information for you to use. It has been a couple of years so I am not sure if it will still work.

 

[Pazzoman]

Thanks A Million zoo diver, also thanks for the idea cu455. This is a small project and its due tomorrow (love procrastination) its ok you don't have to go through the trouble but I will keep you in mind if I have to do another project based on sharks in a class of biology may not be too long from now.