Mammals evolving from birds rather than reptiles.

  • Thread starter Thread starter Jupiter60
  • Start date Start date
Click For Summary
The discussion centers on the controversial idea that mammals may have evolved from birds rather than reptiles. A participant references similarities between birds and monotremes, suggesting a potential evolutionary link. However, the majority counter this notion by citing fossil evidence indicating that cynodonts, ancestors of modern mammals, existed long before birds like Archaeopteryx. The consensus among participants is that mammals and birds evolved along separate evolutionary paths, with no credible scientific support for the idea that mammals descended from birds. Genetic studies further reinforce this view, showing distinct evolutionary branches for mammals and reptiles/birds. The conversation also touches on the concept of convergent evolution, particularly regarding shared traits like the platypus's duck bill, which participants argue arose independently rather than from a common ancestor. Overall, the thread emphasizes the established understanding of mammalian evolution as diverging from reptilian ancestors rather than converging with avian species.
Jupiter60
Messages
79
Reaction score
22
Biology news on Phys.org
Jupiter60 said:
Could mammals have actually evolved from birds?
Cynodonts, an ancestor of modern mammals had been living 110 million years before archaeopteryx did.
 
Jupiter60 said:
Apparently this guy thinks mammals evolved from birds rather than reptiles.

http://www.evolutionem.co.uk/btm106.html

http://www.evolutionem.co.uk/btm107.html

He points out the similarities between birds and monotremes. What do you think about the idea? Could mammals have actually evolved from birds?
Depends on how far back you go.

This is a picture of everybody's great-great-great- ... -great-great-great grand daddy:

Dimetrodon_grandis.jpg

Dimetrodon was a creature which is grouped into what are known as synapsids, due to the construction of their skulls. Synapsids pre-date reptiles as we know them today, but the synapsid line split into two main groups, one group which evolved into sauropsids, which eventually became modern reptiles and birds, and the other group which led to early mammals and eventually present-day mammals.

https://en.wikipedia.org/wiki/Mammal

I'm not aware of any scientist who advocates credibly that mammals, including monotremes, evolved from birds or their early reptile-like ancestors. From the fossil record, any evolvin' of birds and monotremes appears to have occurred along separate lines in time. The duck bill and the egg-laying of the platypus appear to be an evolutionary coincidence.
 
SteamKing said:
The duck bill and the egg-laying of the platypus appear to be an evolutionary coincidence.
I think this is what evolutionists term as convergent evolution.
 
blue_leaf77 said:
I think this is what evolutionists term as convergent evolution.
Yeah, that's the ticket.
 
SteamKing said:
php?image=https%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F5%2F5e%2FDimetrodon_grandis.jpg

That actually looks like my great aunt after she quit smoking about 15 years ago :confused:
 
DNA evidence refutes the possibility that mammals evolved from birds:
Initially, some gene sequences suggested a close relationship between birds and mammals, although never with strong statistical support (e.g., Bishop & Friday, 1987; Goodman et al., 1987; Hedges et al., 1990). More recently, a study of the molecular evidence for the origin of birds (15 genes; 5280 nucleotides, 1461 amino acids) discovered strong support (100% bootstrap P value, BP) for a close relationship between birds and crocodilians (Hedges, 1994). A smaller data set of 11 transfer RNA genes (686 sites) also resulted in a bird-crocodilian grouping (Kumazawa & Nishida, 1995). A basal position for mammals was supported (99% BP) by analysis of a 3 kilobase portion of the mitochondrial genome containing the two ribosomal RNA genes (Hedges, 1994).
(http://tolweb.org/Amniota/14990)

In other words, if you look at shared gene sequences between birds, mammals, repltiles, and other amniota, it's clear that mammals and all of their relatives fall on one branch and reptiles and birds fall on the other branch:
amniota61.png

These relationships are supported by the synapsids fossils referenced by SteamKing above.

Here's a link to the Hedges 1994 study referenced in the quote that refutes the mammal-bird connection: http://www.pnas.org/content/91/7/2621.long
 
Last edited:
But seriously folks...

SteamKing said:
I'm not aware of any scientist who advocates credibly that mammals, including monotremes, evolved from birds or their early reptile-like ancestors. From the fossil record, any evolvin' of birds and monotremes appears to have occurred along separate lines in time.

Yeah, I'd have to agree with this. At least from the perspective of brain evolution, mammals and birds took two fundamentally different paths in their development of advanced brain structures over their more ancestral forms. The mammalian brain evolved a neocortex out of the dorsal pallium of the amphibian-reptile primordial structure, while the avians developed a hyperstriatum out of the more subcortical dorsal ventricular ridge. These are two distinct paths of evolution.
 
blue_leaf77 said:
I think this is what evolutionists term as convergent evolution.

Why would you think this was more convergent versus divergent evolution? The monotremes including the platypus and the echidna are the most primitive of egg laying mammals next to the egg-laying reptiles. Doesn't this make sense that these are species diverging in their evolution from their reptilian ancestors rather than converging from who and what knows where? Where is this converging egg laying behavior and duck-billed phenotypy coming from?
 

Similar threads

  • · Replies 14 ·
Replies
14
Views
10K
  • · Replies 10 ·
Replies
10
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 15 ·
Replies
15
Views
45K
Replies
10
Views
8K
  • · Replies 4 ·
Replies
4
Views
1K
Replies
12
Views
3K
  • · Replies 75 ·
3
Replies
75
Views
11K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K