The question is quite explanatory in it self, I used to think that both are same but then find somewhere that embryology is a part of developmental biology, can somebody please elucidate?
$\begingroup$ Do worms have embryos? $\endgroup$– terdonOct 31, 2014 at 15:53
$\begingroup$ @terdon they have zygotes. All multicellular organisms have at least some form of reproduction where their offspring pass through a single-cell or few-cell state (though I'm sure there's at least a few exceptions to this). $\endgroup$– telOct 31, 2014 at 16:48
1$\begingroup$ @tel I know, that was just a tongue-in-cheek comment pointing out why not all of developmental biology can be called embryology. $\endgroup$– terdonOct 31, 2014 at 16:53
$\begingroup$ @terdon. Ha hah, all right. Honestly, I thought there was a reasonable possibility that you were an earnest seeker after truth $\endgroup$– telOct 31, 2014 at 17:27
$\begingroup$ Does C elegans not have an embryonic stage? $\endgroup$– canadianerNov 1, 2014 at 3:51
It's a simple sub-set relationship, embryology is a sub-set of developmental (it's a "specialty"). Embryology is only concerned with the embryo - developmental is a larger group, concerned with developments that may occur in other stages of life. Such as the development of secondary sexual characteristics in humans - a developmental thing, but not embryonic.
These are not purely objective definitions and the dividing lines are not well defined. Labels for various scientific fields are only generally applicable, and they are very flexible. For example, many Chemists also do a lot of physics. Many Biologists do a lot of Chemistry. Many Embryology studies dip into developmental stuff. These divisions are not always clear.
Embryology is a part of Developmental Biology in the same way that Biology is part of "Science" - simple sub-set relationship. If you don't understand sub-sets very clearly, you'll want to study up on that relationship - it's very important in ALL sciences, so you can understand things like "All squirrels are animals, but not all animals are squirells"
This statement would be reasonable - "All Embrology is Developmental Biology, but some Developmental Biology is NOT Embryology"
$\begingroup$ What I get from your answer is that Developmental Biology along with embryology also concerns itself with regeneration and aging.Will gerontology also be a part of it. $\endgroup$– UserhanuNov 5, 2014 at 10:08
$\begingroup$ See my edit. This stuff is not black and white. And, no I don't know how to explain it without metaphors. $\endgroup$– JasmineNov 5, 2014 at 17:52