The Origin of Birds

20 β€œAnd God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl that may fly above the earth in the open firmament of heaven.

21 And God created great whales, and every living creature that moveth, which the waters brought forth abundantly, after their kind, and every winged fowl after his kind: and God saw that it was good.

22 And God blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let fowl multiply in the earth.

23 And the evening and the morning were the fifth day.”

Genesis 1:20-23

β€œAll flesh is not the same flesh: but there is one kind of flesh of men, another flesh of beasts, another of fishes, and another of birds.”

1 Corinthians 15:39

The Naturalistic Worldview:

Naturalists believe reptiles have evolved into both birds and mammals.

Key Changes Needed:

The development of modified forelimbs, feathers, a 4-chambered heart, air sacs, and hollow bones would be needed to allow reptiles to evolve into birds.

Similarities and Differences:


1. Both are vertebrates.

2. Both breathe through lungs.

3. Both their young ones hatch out of eggs laid by them. However, some reptiles directly give birth to young ones.

4. They show some skeletal similarity for example both reptiles and birds have occipital condyles. These enable the skull to articulate with the vertebral column.

5. They both have a single middle ear bone called the oscicles. 6. The jaws of both reptiles and birds are composed of fused bones which are five in number.


1. Hearts: Reptiles and amphibians generally have three-chambered hearts. Mammals and birds have four-chambered hearts.

2. Lungs: Birds have tube type lungs, reptiles have sack type lungs.

3. Reproductive Activity: For mating purposes: birds build nests, dance, and sing. Reptiles do not have distinctive courtship behaviors like birds. Reptiles leave their young ones to feed for themselves whereas birds take care of their young until they reach the age they are capable of taking care of themselves.

4. Body Coverings: Birds have feathers, while reptiles have scales. Feathers come from different genes than scales and attach differently to the skin.

5. Metabolism: Birds have the highest metabolic rate on earth, reptiles have a very low metabolic rate.

6. Regulating Body Heat: Birds have a system to regulate body heat, reptiles do not.

7. Growth Limits: Birds reach a growth limit and stop; reptiles keep growing until they die.

8. Skin and Glandular System: Birds have tender skin with glands; reptiles have tough skin with no glands.

9. Bones: Birds have light hollow bones; reptiles have dense heavy bones.

10. Muscles for Flight: Birds have the muscles for flight, reptiles have no muscles for flight.

11. Eggs: Birds have hard shelled eggs, and reptiles have leathery eggs.

12. The Thigh Bone: The thigh bone in birds is fixed and not moveable as in other land animals which keeps their air-sac lung from collapsing when the bird inhales during flight.

Reptiles are extremely different from birds. So much so, that you would just about have to redesign them from the inside out, to turn one into another. Those with a supernatural worldview believe God created them as separate "kinds," and intended for them to remain that way, except for speciation within their created "kind."