I need examples of transitional fossils or living creatures.?

Question

I don't mean intermediates, I mean animals that don't have the functioning part, but some sort of step between the fully functioning organ and one without the organ at all.

Answer 1

The gas bladder -- primordium to the lung.

The five aortic arches of the earthworm -- bands of muscle that propel blood, but not a closed heart.

Answer 2

The simple answer is that ALL creatures are 'transitional' creatures.  Nature does not say 'I want to get from here to there, what do I need in the middle?'  The change is constant and continuous.  Even ourselves are transitional forms for what will come next.

How about, ohhhhhhhhh, the lungfish for something interesting to look at?

Answer 3

"Dog" is transitional between gray wolf and mini-dachshund.

The step between laying eggs and placental would be ovoviviparous creatures.  There are plenty of ovoviviparous creatures.

Answer 4

I've no idea how a "transitional fossil" cannot be said to be also "intermeidate".  The logic of that, if any, escapes me.

Transitional between basal mammals and derived mammals, such as placentals and marsupials, is the duckbilled platypus.  However, it's also blessed with derived features of its own.  Transitional between non-mammalian therapsids and mammals are cynodonts including /Thrinaxodon/, /Cynognathus/ and /Pachygenelus/.

Update

<<What I don't understand is some transitional step between, let's say a creature that lays eggs and a creature that has a placenta.>>

A transitional stage between that is imitated by most marsupials, which neither lay eggs and nor have they developed placentas.  A few marsups, however, including koalas if I remember correctly, have gone on to develop relatively simple placentas.  (I'm not suggesting they're somehow ancestral to placental mammals, as they aren't.)

Answer 5

There aren't any. To think that a system could go from an egg laying system to a placenta system is ridiculous.

If you wanted to line up bones you found in the dirt and try to show a progression of how it might have happened using animals that got a little bigger or smaller or bumpier, this would be a gross oversimplification of an immensely complicated circumstance.

Punctuated equilibrium makes matter worse. To say that complicated changes must happen quickly because we don't see fossil evidence for gradual change no good.

It reminds me of a cartoon I saw. A rooster was strangling his wife, the hen, and in front of them was an broken egg with a baby elephant walking out.

The truth is that Jesus originally made all the basic kinds of animals. He made a very diverse bunch of basic kinds. Each with the ability to live in a different part of the earth. Each with a very rich genetic ability variation. (The common dog from which all the other breeds came from was deep in genetic ability for variation, a chawawa is not)

We see the created kinds living out their God given ability to vary. This is called micro-evolution. This is part of science. The Godless people of this world would want you to believe that this means a Dinosaur can turn into a hummingbird or an egg layer can make a placenta user. They can't and that's not part of science, that religion.