Bony Osteichthyes

Devonikauden elämää meressä
kuva University of Michigan Museum of Paleontology

And God said, “Let the water teem with living creatures, and let birds fly above the earth across the vault of the sky.” So God created the great creatures of the sea and every living thing with which the water teems and that moves about in it, according to their kinds, and every winged bird according to its kind. And God saw that it was good. God blessed them and said, “Be fruitful and increase in number and fill the water in the seas, and let the birds increase on the earth.” And there was evening, and there was morning—the fifth day.
Genesis 1:20-23

And so it happened..

Osteichthyes (osteo ikhthys bony fish) have bony skeleton supported by calcium salts. Sharks and their relatives have cartilage body without hard bony skeleton.

Bony fish are among the most fruitful among God's creations. Humans have recorded over 20.000 species, which is statistically highest among all vertebrates. Four-fifth of planet Earth is covered by water so there is room for many kinds of fish.

Osteichthyes are divided into 34 major subspecies

Bony fish have

• jaw
• bony skeleton
• skin covered by scale (some exceptions)
• fin pairs 
• tooth (some exceptions)
• gills protected by bony shields (operculum) Shark gills lack this.

Fernback education Osteichtyes 

Gills - oxygen in water 

Microscope image of fresh water fish gill surface
wikimedia

Gills are a module used by many creatures living in water and corresponds to lungs of land animals.Gills take oxygen directly from water and use them to "breath out" carbon dioxide.

Water has 50 times less oxygen (5gr in cubic meter of fresh water) then atmosphere  (250gr in cubic meter of air). To get as much oxygen as possible into blood the gills must be very thin and folded  (see more in wikipedia)

Swim bladder

The swim-bladder is another mircacle of creation
wikimedia

Only bony fish have the amazing swim-bladder module. Darwin was thinking that these are related to the evolution of lungs in land animals. The module is not used for breathing but rather gives the fish ability to raise or sink deeper or hover at level in water without swimming. Sharks and other cartilage fish need to swim in order to stay put or dive deeper or raise higher in water. Bony fish fill the bladder through mouth and let air out as the bubbles familiar to us in aquariums. 

One of the wonders of the elastic swim-bladder is the fact that it is airtight. Gases do not penetrate the surface because it is covered from inside by guanine crystals.

So what you say! Having lost all your ability to wonder like a child, haven't you?

Guanine crystals inside the fish bladder?

Guanine molecyle
wikimedia

Guanine C₅H₅N₅O molecule has five carbons, five hydrogens, five nitrates and one oxygen atom. When bound they form one of the alphabets of DNA (ACTG).

Adam's children learned to know guanine from bird droppings in 1844 (sp. guano) and it is a valuable fertilizer on fields maintained by humans. (wikipedia)

Fish bladder does not smell all that well. However, Parisian master of fragrances, François Jaquin, invented in 1656 a method to use guano crystals to improve rose water. Today G-crystal is used for example in shampoos. This link gives an animated picture of the 3D sturcture of these crystals and more information about this wondrous organic material.


Miracles of Devonian life
After I have pointed out in very superficial way just some features of fish you are welcome to join me in wondering the bony fish, Osteichthyes, that begins to appear and then practically fills Devonian seas and fresh water sources.

If you are under the impression that modern evolutionary science has satisfactorily explained the origins of bones, scales, fins, gills and guanine-crystal plated swim bladders you still do not know as you should know!

"Now about food sacrificed to idols: We know that “We all possess knowledge.” But knowledge puffs up while love builds up. Those who think they know something do not yet know as they ought to know. But whoever loves God is known by God."
St Paul 1 Corinthians 8.1-3 NIV