Welcome to the seventh installment of my egg themed series. I am more than halfway to my goal of a dozen egg posts! And since I am over the hump I thought it might be good time for a recap. My first egg post (when I conceive this whole silly notion) was an egg garland craft. My second was egg picture books, next an illustrated coll-egg-tion, then came egg shaped Easter basket gift ideas, also egg inspired design, and yesterday was crayon egg decorating. Wow! That’s a lot of egg posts! And now after all that eggy fun I thought it might be time to step back and learn a little bit about this so called egg. So let’s get crackin!
An egg is a usually roundish vessel laid by female birds, most reptiles, mollusks, most fish, insects, and monotremes (monotremes are mammals that lay eggs of which there are just a couple both found only in Australia and New Guinea, the platypus and spiny anteaters).
Here is a great illustration of different egg types by Adolphe Millot (1897-1904)…
Isn’t this a great image! See number 53? It is a Mermaid’s Purse. Come on back tomorrow to watch a fun little video I took of some!
Let’s learn a little bit about an egg’s parts and what they are for!
If an egg is fertilized it becomes a protective home for a little creature to develop. Here is a simplified diagram of what’s inside an egg.
Inside the shell is an inner and outer membrane (these layers stay attached to the shell when you crack an egg). Between these two membranes is an air cell that gets larger over time because the shell is porous and water vapor escapes. Also it happens to be where a chick gets its first breath before hatching! Past the membranes is the albumen or egg white which contains water and protein for the growing creature. The yolk, which is also a food source, is suspended by the chalazae which helps protect the egg and also allow the yolk to rotate so the embryo is always facing up to be closest to incubation source or its mama! The embryo develops from the germ spot or ovum if fertilized.
Print out this educational accordion egg diagram slash greeting card to reinforce our learnings.
Print the following PDF: egg anatomy printable, carefully cut it out, zigzag fold it along the gray lines, color the yolk, and label the parts. If you like you can have a little fun decorating the cover or how about trying to render a unique bird egg from the Millot illustration.
Most eggs are fertilized inside the mother but some are not like many fish. Also did you know that virgin births do occur in the animal kingdom?! This strange phenomena called parthenogenesis has been seen in Komodo Dragons and the New Mexico Whiptails who only reproduce this way since they are are females!