(Embryonic development)

(fertilization)

(external fertilization)

(internal fertilization)

(oviparous reproduction)

(viviparous reproduction)

(ovoviviparous reproduction)

(amnion):

(allantois):

(yolk sac):

(; chorion): ,

(Extra-embryonic membranes)

(embryonic cleavage)

(holoblastic cleavage):

(, , )

( meroblastic cleavage):

(, , )

()

()

( )

( )

( )

()()

()

()

()

()

()Morula

()

Early embryology ( )

After fertilization, zygote ( , )

(1) Egg cleavage (): a series of mitotic division ( )

produce progressively smaller cells ( )

1) Morula () : a solid ball of cells( )

2) Blastula () : a hollow ball of cells( )

3) Gastrula () : mitotic division continue

& transform the blastula into a gastrula ( )

-> gastrulation ()completed by the formation of three embryonic tissues or germ layers

( )

()

() ()

()

(, )

( )

()

:- (endoderm) (mesoderm)

protostomes- blastopore mouth ( ) : - mollusks, annelids, arthropods

(, , )

etrostomes- blastopore anus ( ) - echinoderms and chordates

(, )

()

()

()

()

()

()

(,)

()

()

()

()

Cells of blastoderm( )

Cells growing over yolk service( )

Yolk - large amount( - )

Contrasting patterns of early development( )

()

(Vertebrate) : (Galliformes) -

: (Phasianidae) - : (Gallus) : (Gallus domesticus)

(true egg); + +

(calcareous shell);

(albumin);

(chalaza);

(shell membrane);

.

.

.

( )

.

Vs.

Materials

, (; 15 ), , 70% Ethanol, , , , ,

Method

1. .2. .3. 3cm

.4. ;

5. ,

.6. (true egg) . 7. .8.

.

9. 7, 14, 20 .

, ,

- -

!

periblast

blastoderm

Yolk Segmentation cavity

.

(ectoderm): , ,

(endoderm):

, ,

(embryonic gut):

.

ectodermal cells

endodermal cells

periblast

(: primitive streak)

16 (primitive groove), (primitive ridge), (primitive pit) (blastopore)

Chicken embryo, 21 hours.

Credit: Carolina Biological/Visuals Unlimited 310816

(Primitive streak);

(primitive ridge);

Chicken embryo, 43 hours.

Credit: Carolina Biological/Visuals Unlimited 310877

(amnion) (somites)

(heart)

(Primitive streak)

Primitivestreak ectoderm Neural tube

brain

heartForegutyolk

brain optic cup

oticvesicle heart

vitelline vein

vitelline artery

somite

neural tube

neural groove

primitive streak

Chicken embryo, 60 hours.

Credit: Carolina Biological/Visuals Unlimited 310880

(eye)

(somites)(Spinal chord)

(amnion)

(allantois)(heart)

()

Audiroty vesicle

Pharyngeal pouch

Aortic archVentral aortaNeural tube

Anterior limb bud

Dorsal aorta

Kidney area

Posterior limb buds

Endolymphatic duct

Optic cuplens

Olfactory pitventricle

Liver bud

Yolk stalk

allantois

Tail bud

()

Chicken embryo, 96 hours.

Chicken embryo, 8 days(96 hours).

Credit: Carolina Biological/Visuals Unlimited 310882

9-10 days

Chick embryo, 9 days.

Credit: Carolina Biological/Visuals Unlimited 214169

Chick embryo, 13 days.

Credit: Carolina Biological/Visuals Unlimited 214173

Chick embryo, 16 days.

Credit: Carolina Biological/Visuals Unlimited 214176

Chick embryo, 19 days.

Credit: Carolina Biological/Visuals Unlimited 214179

Newly hatched chick on day 21.

Credit: Jerome Wexler/Visuals Unlimited 211077

Result

28 1-3 . 4

7, 14, 20