Embryological Evidence

1. Embryological Evidences
SANDIP RATHOD

2. Embryology deals with the development of organisms from the egg stage to the adult stage
it is also called ontogeny
1. Egg:
Each animal, whether a worm or fly or a frog or an elephant or a man start development from
single cell, the egg
2. Development stage:
Sandip Rathod

3. 3. Fate of Gastrula:
the gastrula of all animals consist of an archenteron, a blastopore and three germinal
layers, namely ectoderm, mesoderm and endoderm.
Archenteron: alimentary Cavity and the associated glands
Blastopore: Mouth in invertebrate except echinoderm and anus in all chordate
Ectoderm: nervous system, skin
Mesoderm: muscular system, skeleton
Endoderm: Alimentary canal
4. Similarity of embryos:
Sandip Rathod

4. 5. Von Baer's Law:
In the 18th century Von Bear, founder of comparative embryology, contributed much to the
field of embryology and evolution
Sandip Rathod

5. 6. Biogenetic law or Recapitulation theory:
Biogenetic law was postulated by Ernst Haeckel (1861)
This theory says that higher animals in their development passes through stages which
are similar to the adult stages of lower animals, which would be their ancestors.
Ontogeny
Sandip Rathod

6. Phylogeny:
Sandip Rathod

7. This theory can be substantiated by following example
1. Tadpole
2. Teeth in birds:
3. Embryonic stages:
4. Hair in whale embryo
5. Heart:
6. Kidney:
7. Yolk sac:
8. Aortic Arch:
9. Branchial grooves and visceral pouch:
10.Trochophore larva
11.Nauplius Larva
Sandip Rathod

8. 1. Tadpole
2. Teeth in birds
Sandip Rathod

9. 3. Hair in whale embryo
4. Embryonic stages
Sandip Rathod

10. 5. Heart:
6. Kidney
Sandip Rathod

11. 7. Yolk sac:
8. Aortic Arch:
Sandip Rathod

12. 9. Branchial grooves and visceral pouch:
10. Trochophore larva
11. Nauplius Larva
Sandip Rathod

13. Sandip Rathod