What is an organic evolution? It cannot be equated with progress. Explain with the help of a suitable example.

Q: What is an organic evolution? It cannot be equated with progress. Explain with the help of a suitable example.

1. **Organic Evolution:** Organic evolution is the gradual and continuous process of accumulation of variations in organisms over successive generations, driven by environmental selection, which leads to the formation of new species from pre-existing ones. 2. **Why Evolution Cannot Be Equated with Progress:** - Evolution is simply the generation of diversity and the shaping of this diversity by environmental selection. It does not mean that older, simpler body designs are inefficient or completely eliminated. - It is not a ladder of progress from "lower" to "higher" organisms; rather, it is a branching process where new designs emerge as adaptations to specific environmental niches, while simpler designs continue to survive successfully. 3. **Example:** - **Bacteria** are one of the simplest life forms on Earth, having evolved billions of years ago. - Despite the subsequent evolution of highly complex organisms like human beings, bacteria still survive and thrive in highly diverse and extreme environments, such as hot springs, deep-sea thermal vents, and Antarctic ice. - This demonstrates that the simpler design of bacteria is highly efficient for their environment, proving that evolution is about adaptation to the environment rather than a simple march toward "progress" or complexity.

Heredity

Accumulation of Variation during Reproduction

Official Answer

Organic Evolution: Organic evolution is the gradual and continuous process of accumulation of variations in organisms over successive generations, driven by environmental selection, which leads to the formation of new species from pre-existing ones.

Why Evolution Cannot Be Equated with Progress:

Evolution is simply the generation of diversity and the shaping of this diversity by environmental selection. It does not mean that older, simpler body designs are inefficient or completely eliminated.
It is not a ladder of progress from "lower" to "higher" organisms; rather, it is a branching process where new designs emerge as adaptations to specific environmental niches, while simpler designs continue to survive successfully.

Example:

Bacteria are one of the simplest life forms on Earth, having evolved billions of years ago.
Despite the subsequent evolution of highly complex organisms like human beings, bacteria still survive and thrive in highly diverse and extreme environments, such as hot springs, deep-sea thermal vents, and Antarctic ice.
This demonstrates that the simpler design of bacteria is highly efficient for their environment, proving that evolution is about adaptation to the environment rather than a simple march toward "progress" or complexity.

organic evolutionprogressdiversityenvironmental selectionbacteriaadaptation

Marking Scheme

1Defining organic evolution as the accumulation of variations over generations leading to new species. (1 mark)
2Explaining why evolution is not progress (it generates diversity and adapts to environments, rather than making older designs obsolete). (1 mark)
3Providing a suitable example, such as bacteria surviving in extreme environments despite being simpler than complex organisms. (1 mark)

Hint

Recall that evolution is about adaptation to the environment, not necessarily becoming more complex. Think about bacteria.

Quick Oral Answer

Organic evolution is the change in inherited characteristics of populations over generations. It is not progress because simpler organisms like bacteria still survive exceptionally well alongside complex ones.

Analysis & Explanation

Evolution is often misunderstood as a progressive march towards perfection or complexity. However, natural selection only filters variants based on their immediate survival advantage in a given environment. A simpler body design (like that of bacteria) can be highly successful and survive extreme conditions where complex organisms would fail. Therefore, evolution is about adaptation and diversity, not progress.

Common Mistakes

1Equating evolution with progress or thinking that simpler organisms are 'less evolved' or 'imperfect'.
2Not providing a clear example to support the explanation.

Interesting Facts

Bacteria, which are among the earliest and simplest life forms, can survive in extreme conditions like deep-sea hydrothermal vents where humans would instantly perish.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2017?

This question carries 3 marks in the CBSE Class 10 Science 2017 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Heredity" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Accumulation of Variation during Reproduction" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2017 paper?

This is a Short Answer question from Section A in the CBSE Class 10 Science 2017 paper.