Monday, December 26, 2016

Science News: Why Prehistoric Insects Were Much Larger

As kids we loved dinosaurs. Recently Earth and Sky online magazine published this interesting article about why prehistoric insects were much larger than they are today. It's interesting and worth reading. We edited it to make it shorter. 

Why were prehistoric insects so huge?

Before the dinosaurs, giant insects ruled the world more than 300 million years ago.
  Consider Meganeura, a genus of extinct insects from approximately 300 million years ago, related to modern-day dragonflies. One member of this group – M. permiana – was first described by researchers in Kansas in 1937 as having a wingspan of over 2 feet (0.6 meters). It’s still considered one of the largest known insects that ever lived.
   While over a million insect species live today, truly giant insects no longer exist. Why did they disappear?
There are two main reasons. The most important is that our atmosphere has changed. Millions of years go, the air surrounding our planet was warmer, moister and contained more oxygen. During the Carboniferous and Permian periods, Earth’s air contained 31-35% oxygen, as compared to just 21% oxygen in the air today.
Oxygen levels are especially important for insects because they don’t have lungs. Instead, they rely on air flowing through a series of opening across their bodies called spiracles, which connect directly to the tissues that need oxygen.
M. monyi - whose fossilized remains are shown here - is one of the largest known flying insect species; the Permian Meganeuropsis permiana is another.  This specimen is housed at the Fossil at the Museum of Natural History in Toulouse. Image via Wikimedia Commons.
Fossil remains of M. Monyi, a member of the extinct insect genus Meganeura. Their wingspans could reach 2 feet
 There’s another reason giant insects disappeared. As ancient dinosaurs evolved  and some developed the ability to fly, eventually becoming modern birds, they put a cap on insect size through predation and competition.
The earliest known bird – Archaeopteryx – appeared about 150 million years ago. Birds proved to be faster and more agile than the giant insects. In an article in LiveScience in 2012, paleobiologist Matthew Clapham of the UC Santa Cruz commented:
The change in insect size is gradual. This gradual change fits quite nicely with the gradual evolution in birds at the time.

Bottom line: Hundreds of millions of years ago, giant insects were common on Earth. The decline in atmospheric oxygen – and the rise of birds – both contributed to the demise of these prehistoric insects.
Where giant insects fit in the history of life on Earth.
Where giant insects fit in the history of life on Earth.

Gift/Memorial Suggestions

Several of our friends have lost loved ones (human and pets) and we found that one of the best ways to honor their memory is to give to an animal charity.
What better way to recognize a life of love, than by giving another life a chance for love?
We donate to many animal rescues, but because we volunteer with
DC Weimaraner Rescue and Coast-to-Coast Dachshund Rescue, those are our 2 favorites.
Consider giving the chance of life to a dog or cat.

About us

We're two married guys who enjoy the simple things in life, especially our dogs. We volunteer for dog rescues, enjoy splitting dinners, exercising, blogging, helping friends and neighbors, ghost investigations, coffee and tea, Tudor history, weather, superheroes, comic books, mystery novels, traveling, 70s and 80s music, classic country, piano, gardening, writing books on ghosts and spirits, architecture, keeping a clean house, cooking simply, and keeping in shape. You'll find tidbits of all of these things on this blog and more.

Tom and Rob Thinking Hard!

Tom and Rob Thinking Hard!
Wondering what home project to do next