The very intresting example of recapitulation is the development of man . The recapitulation theory was proposed by Von Baer .This theory was revised and renamed by an embryologist (Ernst Haeckel in 1868) .We can compare the develpomental stages as follows-
1. The fertilised egg can be compared with the single celled ancestor of all metazoan .
2.The blastula may be compared to a colonial protozoan which might be the ancestor of metazoa.
3.Gastrula represents the coelenterate ancestor .
4.The embryo with the development of mesoderm represents tripoblastic stage like a flatworm .
Structures resemble to chordate embryo -
1.Early human embryo with a dorsal hollow nerve cord .
2. A well developed notochord.
3.A series of gill-slits .
Structures resemble to fish embryo -
1. The development of piscine heart .
2.Paired of aortic arches .
3.Primitive pronephros and a tail .
Later on it resembles to reptilian embryo and then to mammalian embryo . It means embryonic development (ontogeny ) in man recapitulates or replay the evolutionary history . (phylogeny ).
Ontogeny -Development of an individual organism .
Phylogeny -Evolutionary history or race of the species
Recapitulates - Replay
Evolution cannot go back and change the evolutionary history it can modify what is pre-existing .
Examples of recapitulation in plants -
1. Presence of flagellated sperm and water dependency for fertilisation in both terrestial plants (pteridophytes and gymnosperms ) and animals.
2.Presence of filamentous protonema during development of moss.(Funaria)
3.Seedlings of Acacia tree initially develop simple leaves which later get transformed into compound leaves .
4.Oak tree from southern united states retain their leaves through out the year ,whereas oaks from Northern united states shed their leaves during winter and are deciduous .
MCQs-
1.Theory of biogenetic law was proposed by -
1) A. Weismann
2) E. Haeckel
3) De Lamark
4) A.R. Wallace Ans. 2
b)High rate of reproduction
c)Mutations in the embryonic stage
d)Atavism Ans.1
2) tadpole larva of frog
3) placenta of mammals
4) canine teeth of frog Ans.2
6.Basic principles of embryonic development were pronounced by
1. The fertilised egg can be compared with the single celled ancestor of all metazoan .
2.The blastula may be compared to a colonial protozoan which might be the ancestor of metazoa.
3.Gastrula represents the coelenterate ancestor .
4.The embryo with the development of mesoderm represents tripoblastic stage like a flatworm .
Structures resemble to chordate embryo -
1.Early human embryo with a dorsal hollow nerve cord .
2. A well developed notochord.
3.A series of gill-slits .
Structures resemble to fish embryo -
1. The development of piscine heart .
2.Paired of aortic arches .
3.Primitive pronephros and a tail .
Later on it resembles to reptilian embryo and then to mammalian embryo . It means embryonic development (ontogeny ) in man recapitulates or replay the evolutionary history . (phylogeny ).
Ontogeny -Development of an individual organism .
Phylogeny -Evolutionary history or race of the species
Recapitulates - Replay
Evolution cannot go back and change the evolutionary history it can modify what is pre-existing .
Examples of recapitulation in plants -
1. Presence of flagellated sperm and water dependency for fertilisation in both terrestial plants (pteridophytes and gymnosperms ) and animals.
2.Presence of filamentous protonema during development of moss.(Funaria)
3.Seedlings of Acacia tree initially develop simple leaves which later get transformed into compound leaves .
4.Oak tree from southern united states retain their leaves through out the year ,whereas oaks from Northern united states shed their leaves during winter and are deciduous .
MCQs-
1.Theory of biogenetic law was proposed by -
1) A. Weismann
2) E. Haeckel
3) De Lamark
4) A.R. Wallace Ans. 2
2.Haeckel’s recapitulation theory states:
a)Ontogeny recapitulates phylogenyb)High rate of reproduction
c)Mutations in the embryonic stage
d)Atavism Ans.1
3.In plants recapitulation theory in -
1-Oenothera lamarkiana
2-Pisum sativum
3-Acacia
4-none Ans.3
2-Pisum sativum
3-Acacia
4-none Ans.3
4.Presence of gill slits in the embryos of all vertebrates supports the theory of -
a. Organic evolution
b.Biogenesis
c.Metamorphosis
d.Recapitulation Ans.4
5."A good example for recapitulation theory" is
1) embryonic membranes of reptiles2) tadpole larva of frog
3) placenta of mammals
4) canine teeth of frog Ans.2
6.Basic principles of embryonic development were pronounced by
(a) Von Baer(b) Weismann(c) Haeckel(d) Morgan. Ans.1
7.In the developmental history of mammalian heart, it is observed that it passes through a two chambered fish like heart, three chambered frog like heart and finally four chambered stage. To which hypothesis can this above cited statement be approximated?
7.In the developmental history of mammalian heart, it is observed that it passes through a two chambered fish like heart, three chambered frog like heart and finally four chambered stage. To which hypothesis can this above cited statement be approximated?
(a) Lamarck’s principle
(b) Mendalian principles
(c) Biogenetic law
(d) Hardy Weinberg law. Ans.c
Explanation -As during embryonic development the mammalian heart first takes the form of fish, then frog and at last mammal.
8.Haeckel's biogenetic law of organic evolution receives support from -
1.palaeontological studies
2.morphological studies
3.embryological studies
4.serological studies Ans.3
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