1. A brief essay on relationships of major animal groups.
ANIMAL EMBRYOLOGY
A brief essay on relationships of major animal groups.
23 Oct. 2014
Embryology.ppt

2. What IS an Animal? Petunia is a plant and Wolf spider is an animal.
No trouble.
23 Oct. 2014
Embryology.ppt

3. What IS an Animal? Coral sessile (“rooted”?) stem, branches, greenish.
Resembles plant;
but this IS an animal! Why?
23 Oct. 2014
Embryology.ppt

4. What IS an Animal? Definition of "Animal"
Multicellular (so are plants, fungi)
Eukaryotic (so are plants, fungi)
Diploid (usually) (sporophytes are, too)
Meiosis produces gametes
Sperm, egg are the only haploid cells
Heterotrophic by ingestion
Cells lack cell walls.
23 Oct. 2014
Embryology.ppt

5. What IS an Animal? Basic structure (not definition) = Tube-in-tube
Body wall = outer tube
gut (GI tract) = inside tube
mouth
anus
23 Oct. 2014
Embryology.ppt

6. Embryological Development in Animals
Every animal begins as ZYGOTE
How do animals develop tube-in-tube body form?
Important in understanding relationships, classification of Phyla.
23 Oct. 2014
Embryology.ppt

7. Quiz question 49
49. Animals can be distinguished from members of other Kingdoms, because animals
a. have cell walls
b. have haploid gametes
c. are heterotrophic by ingestion
d. are prokaryotic
e. are eukaryotic
23 Oct. 2014
Embryology.ppt

8. Three fundamental processes:
1. Morphogenesis
(morph- = shape, + genesis = origin)
Origin of shape, form
2. Differentiation
Process of cells becoming different, and specializing for different functions
3. Growth
Increase in size, requires input of matter, food
23 Oct. 2014
Embryology.ppt

9. Sequence of Events: 1. Fertilization 2. Activation 3. Cleavage
4. Gastrulation
5. Mesoderm formation
6. Organogenesis
23 Oct. 2014
Embryology.ppt

10. Sequence of Events: (frog or sea urchin model)
1. Fertilization
Fusion of sperm nucleus with egg nucleus
Produces zygote (diploid)
2. Activation
Increase in metabolism
Egg metabolically inert, zygote active
Movement of cytoplasm
Synthesis of materials needed for cleavage
23 Oct. 2014
Embryology.ppt

11. Quiz question 50
50. One of the Fundamental Processes in embryonic development is
a. gastrulation
b. cell division by mitosis
c. differentiation of cells
d. increase in size of cells
e. organogenesis
23 Oct. 2014
Embryology.ppt

12. Sequence of Events: 3. Cleavage from Zygote Division by mitosis
2 blastomeres  4 blastomeres  8 blastomeres  16  32  64  128  256  512
 Blastula
23 Oct. 2014
Embryology.ppt

13. Sequence of Events: 4. Gastrulation = formation of a gut;
Major MORPHOGENIC event !!!
Location of cells after GASTRULATION determines further development
23 Oct. 2014
Embryology.ppt

14. Sequence of Events: 4. Gastrulation
Invagination & movement of cells to inside
yields 2 tissue layers
Ectoderm
Endoderm
yields Archenteron
“ancient gut” = first formation of "inside tube."
23 Oct. 2014
Embryology.ppt

15. Quiz question 51
51. Cleavage results in a hollow sphere of 500—1000 cells called a(n)
a. archenteron
b. blastula
c. clavicle
d. dendrite
e. gastrula
23 Oct. 2014
Embryology.ppt

16. Sequence of Events: 5. Mesoderm Formation 3rd "germ layer"
Ectoderm = “outside skin”
Mesoderm = "middle skin"
Endoderm = “inside skin”
Details of mesoderm formation vary among phyla !!
to be studied with those phyla.
23 Oct. 2014
Embryology.ppt

17. Sequence of Events: 6. Organogenesis
Formation of organs from three germ layers
Differentiation & continued Morphogenesis
23 Oct. 2014
Embryology.ppt

18. Organogenesis Ectoderm Epidermis Lining of mouth & rectum
Cornea of eye
Lens of eye
Nervous system
23 Oct. 2014
Embryology.ppt

19. Organogenesis Endoderm forms thin linings (mostly)
linings of gut & branches
lining of excretory ducts, bladder
" " lungs, trachea
" " reproductive ducts,
uterus, vas deferens
liver
pancreas
23 Oct. 2014
Embryology.ppt

20. Organogenesis Mesoderm Skeleton, Muscles (skeletal, smooth, cardiac)
Dermis of skin
Heart, blood, blood vessels
Kidneys,
Ovaries/testes, etc.
23 Oct. 2014
Embryology.ppt

21. Quiz question 52
52. Which of the following is the earliest in the sequence of events in embryonic development of animals?
a. cleavage
b. organogenesis
c. meiosis
d. gastrulation
e. heterotrophy
23 Oct. 2014
Embryology.ppt

22. Organogenesis Ectoderm How Nervous system gets inside
Dorsal surface of embryo forms Neural plate
Plate sinks inward forming Neural groove
Edges of groove fuse to separate Neural tube from epidermis
23 Oct. 2014
Embryology.ppt