Is there any truth to a embryo evolving into a adult human?

Question

I hear so many atheists on the r&s section state that the human sperm "tadpoles" evolve into humans.
they say everytime a baby is born that is proof of evolution.
I'm confused.
I thought that enviromental changes cause evolution.
Someone please explain this to me.
When I was in high school, I was taught the life cycle of humans, nothing about babies evolving into humans.

great answers.
now I'm beginning to understand what they mean.

Answer 1

There are many proposed "evidences" that evolution has occured, such as , the fossil record, homologous structures, vestiges.........others. I believe that you are describing an evidence for evolution called comparative embryology.
This was proposed by Ernst Haekel (German?) in the
late 1800's. He said that "ontogeny recapitulates phylogeny," meaning that as an animal develops(ontogeny), they repeat
(recapitulate) their evolutionary past (phylogeny). He pointed
out, for instance, that during human development, we
had temporary (non-functional) gill slits (like fish) that were
replaced by the inner ear bones. The theory has been met with some opposition.
If you care to see more detail about his idea, go to:

http://en.wikipedia.org/wiki/Embryo_drawings

Answer 2

There is both an informal, and a formal (biology) use of the word "evolve".

The informal use of the word "evolve" just means "slow change." For example, we can sometimes speak of Thomas Jefferson's political views evolving, or the evolution of the English language, or how Anakin Skywalker's character evolves (changes) in the Star Wars movies. And we even speak of the evolution of stars and galaxies and solar systems. So in this informal sense, yes, an embryo "evolves" during the course of development.

However, in the science of Biology, the word "evolution" has a very specific meaning ... namely, slow change AT THE SPECIES OR POPULATION LEVEL. So an embryo's development is NOT biological evolution.

HOWEVER, there are many things that go on during embryological development that *are* evidence of evolution.

For example, mammal embryos go through a phase where they have gill folds, even though no mammal has gills. Humans and other tail-less apes go through phases where they have a noticeable tail. Dolphin embryos go through a phase where they have rear leg buds, evidence of a land-dwelling ancestor. These are all evidence of genes in the embryo that are leftovers from past ancestors (with gills, or a tail, or that walked on land).

So embryo development offers lots of *evidence* of evolution ... but it is not itself called "evolution."

Answer 3

You are right, embryos do not really "evolve" into humans in the sense of the true definition of evolution.

However, what these posters are referring to is that during human embryo development, changes occur that mimic evolutionary changes that humans have undergone throughout history, such as development of a pharyngeal gill slits and tail bud. All vertebrates undergo these same developmental changes when they are embryos. In fact, if someone showed you pictures of sheep, frog, cat, and human embryos it would be difficult to even tell them apart. Many scientists consider this to be one point of evidence for evolution - ie all of these animals look the same when they are embryos because we originated from common ancestors.

Frog embryo:
http://www.uoguelph.ca/zoology/devobio/210labs/34frogwm.GIF


Human embryo:
http://www.sciencemuseum.org.uk/on-line/lifecycle/images/1-2-3-1-5-0-0-0-0-0-0.jpg

Answer 4

I think what they mean is that if you compare embryos of several different organism in early fetal development you will see that these embryos are all very similar at first. A human baby is proof of evolution because embryos which are all so similar and once developed into similar creatures at first now develop into entirely different things, Also genetic changes cause evolution, not environmental ones. So it doesn't mean evolution in the literal sense. Just in the comparitive sense.

Answer 5

An embryo grows into a human baby. It doesn't evolve.
As mentioned above, the fetus goes through several stages, where it looks like a tadpole for a while, then it looks sort of like a lizard, then it looks sort of like a monkey before it starts to look like a baby. These phases are said to be a reflection of our evolution from lower animals. It's an interesting comparison, but doesn't really prove anything.

Answer 6

While evolution is a reality, those statements could not be more uninformed, A fertilized egg growing into a human being is not an example of evolution. Evolution is a process by which species arise from other species. Not only is a fetus not a seperate species from a human, but evolution is a process that takes place over thousands of years, not 9 months.