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?

Options

A. Lamarck's principle
B. Medelian principles
C. Biogentic law
D. Hardy Weinberg law

Answer

To solve the question regarding the developmental history of the mammalian heart and the hypothesis it aligns with, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Developmental Stages**: The mammalian heart goes through three key stages during its development:
- A two-chambered heart similar to that of fish.
- A three-chambered heart similar to that of frogs (amphibians).
- Finally, it develops into a four-chambered heart, characteristic of mammals.

2. **Identify Relevant Hypotheses**: The question provides several hypotheses to consider:
- Lamarck's Principle
- Mendelian Principles
- Biogenetic Law
- Hardy-Weinberg Law

3. **Analyze Each Hypothesis**:
- **Lamarck's Principle**: This principle focuses on physical changes in organisms during their lifetime, which does not directly relate to the embryonic development of the heart.
- **Mendelian Principles**: These principles pertain to inheritance and genetics, which do not explain the developmental stages of the heart.
- **Biogenetic Law**: Proposed by Ernst Haeckel, this law states that "ontogeny recapitulates phylogeny," meaning that the development of an individual organism (ontogeny) reflects the evolutionary history of its species (phylogeny). This aligns with the observation that the mammalian heart develops through stages that resemble those of earlier vertebrates.
- **Hardy-Weinberg Law**: This law deals with allele frequencies in populations and does not pertain to the developmental stages of the heart.

4. **Select the Correct Hypothesis**: Based on the analysis, the biogenetic law (recapitulation theory) is the most appropriate hypothesis that explains the developmental stages of the mammalian heart, as it reflects the evolutionary history of heart development through its stages.

### Final Answer:
The developmental history of the mammalian heart, which passes through a two-chambered fish-like heart, a three-chambered frog-like heart, and finally a four-chambered stage, can be approximated to the **Biogenetic Law**.

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