23 oct. 2014embryology.ppt1 animal embryology a brief essay on relationships of major animal groups

23 Oct. 2014 Embryology.ppt 1

ANIMAL EMBRYOLOGY

A brief essay on relationships of major animal groups.


What IS an Animal?

• Petunia is a plant and• Wolf spider is an

animal.

• No trouble.


What IS an Animal?

• Coral• sessile (“rooted”?)

• stem, branches,

• greenish.

• Resembles plant;but this IS an

animal! Why?


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 ingestionCells lack cell walls.


What IS an Animal?

• Basic structure (not definition) = Tube-in-tube Body wall = outer tube gut (GI tract) = inside tube

• mouth

• anus


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.

Quiz question 49

• 49. Animals can be distinguished from members of other Kingdoms, because animalsa. have cell walls

b. have haploid gametes

c. are heterotrophic by ingestion

d. are prokaryotic

e. are eukaryotic

723 Oct. 2014 Embryology.ppt


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


Sequence of Events:

1. Fertilization

2. Activation

3. Cleavage

4. Gastrulation

5. Mesoderm formation

6. Organogenesis


Sequence of Events:(frog or sea urchin model)

1. Fertilization• Fusion of sperm nucleus with egg nucleusProduces zygote (diploid)

2. Activation• Increase in metabolism

• Egg metabolically inert, zygote active

• Movement of cytoplasm• Synthesis of materials needed for cleavage

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



Sequence of Events:

3. Cleavage• from Zygote• Division by mitosis

• 2 blastomeres 4 blastomeres 8 blastomeres 16 32 64 128 256 512

Blastula


Sequence of Events:

4. Gastrulation = formation of a gut; • Major MORPHOGENIC event !!!

• Location of cells after GASTRULATION determines further development


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."

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



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.


Sequence of Events:

6. Organogenesis• Formation of organs from three germ layers

• Differentiation & continued Morphogenesis


Organogenesis

• Ectoderm• Epidermis

• Lining of mouth & rectum

• Cornea of eye

• Lens of eye

• Nervous system


Organogenesis

• Endoderm forms thin linings (mostly)• linings of gut & branches

• lining of excretory ducts, bladder

• " " lungs, trachea

• " " reproductive ducts, • uterus, vas deferens

• liver

• pancreas


Organogenesis

• Mesoderm• Skeleton,

• Muscles (skeletal, smooth, cardiac)

• Dermis of skin

• Heart, blood, blood vessels

• Kidneys,

• Ovaries/testes, etc.

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



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. 2014embryology.ppt1 animal embryology a brief essay on relationships of major animal groups

Documents

cleavage slide

development slide

blastula slide

organogenesis slide

food slide

ppt1 animal embryology

tube mouth anus slide

size of cells