巨齿鲨-史上最大的鲨鱼.ppt

巨齿鲨史上最大的鲨鱼MegalodonThe Largest Shark that Ever Lived
Megalodon Exhibit Background
Will be open at the Florida Museum of Natural History from June 16th – Dec. 31st 2007.
Focal point of the exhibit is a 60-foot model of a Megalodon shark that visitors will be able to walk through.
Dr. Bruce MacFadden and Bob Purdy discussing the plans
If Shark Teeth Could Talk
Shark teeth can:
Identify the species
Lemon Shark
Mako Shark
If Shark Teeth Could Talk
Shark teeth can:
Sometimes indicate body size
Megalodon
Whale Shark
If Shark Teeth Could Talk
Shark teeth can:
Indicate prey or prey size
Great White Shark
Basking Shark
This Was One Big Shark!
Scientists still debate Carcharodon (or Carcharocles) megalodon’s size
Different analysis = Different size estimates
All studies conclude Meg was huge!
Most scientists feel Megalodon was between 45-60 feet long
The Circle of Life
A shark’s skeleton posed of cartilage, which does not preserve in the fossil record
However, shark vertebrae do calcify
Growth rings are preserved in shark vertebrae
Shark vertebrae are discs which are called centra
Growth rings are recorded in these centra
Number of rings indicates the shark’s age at death
Shark centrum
Tree rings
Centrum with growth rings
What did Megalodon Eat?
Megalodon was the top predator of its time
It would need to eat a lot to survive
An adult female probably weighed over 100 tons
Megalodon most likely ate whales, large fish, seals, sea turtles, and whatever else it wanted!
Estimates show Megalodon would average 2,500 lbs of food per day!
When Was Megalodon Alive?
Megalodon lived from about 20 to 2 million years ago
Fossil teeth and (rarely) centra are found in ancient marine sediments
Megalodon is extinct!
Meg evolved to eat giant whales
that appeared as the oceans
cooled in the Miocene and
Pliocene