In the developmental history of mammalian heart, it is observed that i...
Biogenetic law or Recapitulation theory was given by Ernst Haeckel in 1866. It states that 'ontogeny repeats phylogeny'. Ontogeny is the life history of an organism while phylogeny is the evolutionary history of the race of that organism. This means that an organism repeats its ancestral history during its development.
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In the developmental history of mammalian heart, it is observed that i...
< b="" />Explanation:
The statement mentioned in the question is related to the concept of the Biogenetic law, which is option C.
The biogenetic law, also known as the recapitulation theory or embryological parallelism, was proposed by Ernst Haeckel in the 19th century. According to this law, the development of an organism (ontogeny) reflects its evolutionary history (phylogeny). It suggests that the embryonic development of an organism passes through stages that resemble the adult forms of its evolutionary ancestors.
< b="" />Development of the mammalian heart:
The development of the mammalian heart is a gradual process that involves the formation of different chambers. It can be traced back to the evolutionary history of vertebrates.
< b="" />Two-chambered fish-like heart:
In fish, the heart consists of two chambers - an atrium and a ventricle. The blood flows in a single circuit, where deoxygenated blood from the body is pumped to the gills for oxygenation and then back to the body.
< b="" />Three-chambered frog-like heart:
In frogs and other amphibians, the heart consists of three chambers - two atria and one ventricle. The two atria receive oxygenated blood from the lungs and deoxygenated blood from the body, respectively. The mixing of oxygenated and deoxygenated blood occurs in the ventricle, and a mixture of oxygenated and deoxygenated blood is pumped out to the body.
< b="" />Four-chambered mammalian heart:
In mammals, including humans, the heart consists of four chambers - two atria and two ventricles. The two atria receive oxygenated blood from the lungs and deoxygenated blood from the body, respectively. The two ventricles pump the oxygenated and deoxygenated blood separately to the systemic and pulmonary circulations.
< b="" />Applying the Biogenetic law:
The developmental stages of the mammalian heart, as described above, resemble the adult forms of its evolutionary ancestors. This supports the concept of the biogenetic law, which suggests that ontogeny recapitulates phylogeny. The development of the mammalian heart reflects its evolutionary history from the two-chambered fish-like heart to the three-chambered frog-like heart and finally to the four-chambered stage.
Therefore, the statement mentioned in the question can be approximated to the hypothesis of the biogenetic law.
In the developmental history of mammalian heart, it is observed that i...
Explanation:
The statement provided in the question describes the developmental history of the mammalian heart, which starts with a two-chambered fish-like heart and progresses to a three-chambered frog-like heart and finally to a four-chambered heart. This pattern of heart development follows a principle known as the biogenetic law.
Biogenetic Law:
The biogenetic law, also known as the recapitulation theory or embryological parallelism, was proposed by Ernst Haeckel in the late 19th century. According to this law, the development of an individual organism (ontogeny) recapitulates the evolutionary history of the species (phylogeny). In other words, the stages of embryonic development reflect the developmental stages of ancestral species.
Application to the Mammalian Heart:
The development of the mammalian heart follows the biogenetic law, as observed in the statement provided. Here is how the different stages correspond to the ancestral stages:
1. Two-Chambered Fish-Like Heart:
In fish, the heart consists of two chambers - an atrium and a ventricle. This stage is represented by the first stage mentioned in the statement, which describes a two-chambered heart. This stage reflects the ancestral condition of the heart in fish-like ancestors.
2. Three-Chambered Frog-Like Heart:
In frogs and other amphibians, the heart consists of three chambers - two atria and one ventricle. This stage is represented by the second stage mentioned in the statement, which describes a three-chambered heart. This stage reflects the ancestral condition of the heart in frog-like ancestors.
3. Four-Chambered Stage:
In mammals and birds, the heart consists of four chambers - two atria and two ventricles. This stage is represented by the final stage mentioned in the statement, which describes a four-chambered heart. This stage reflects the advanced condition of the heart in mammalian ancestors.
Conclusion:
Based on the observation that the developmental history of the mammalian heart follows the sequence of a two-chambered fish-like heart, three-chambered frog-like heart, and finally a four-chambered heart, the statement can be approximated to the hypothesis of the biogenetic law. According to this law, the stages of ontogeny (development) recapitulate the stages of phylogeny (evolutionary history).
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