BIOLOGY- REPRODUCTION IN ORGANISM LIFE SPAN Part 2.

https://www.gyanodhan.com/video/3B1.%20Class%2011%20and%2012%20IIT%20NEET/Biology/120.%20BIOLOGY-%20REPRODUCTION%20IN%20ORGANISM%20LIFE%20SPAN%20Part%202.mp4]

Here’s Part 2: Life Span in Organisms (Reproduction in Organisms)

LIFE SPAN OF ORGANISMS

What is Life Span?

The life span of an organism is the period from its birth to its natural death. It varies greatly among different species.

Life Span of Different Organisms

• Short-lived organisms:
  • Mayfly – 1 day
  • Rice plant  – 3-4 months
• Moderate life span:
  • Dog  – 10-15 years
  • Cow  – 20-25 years
• Long-lived organisms:
  • Elephant  – 60-70 years
  • Human  – 80-100 years
  • Banyan tree  – 200-500 years
  • Tortoise  – 100-250 years

Life Span vs. Size

• Life span is not necessarily related to the size of an organism.
  • Example: A parrot (140 years) lives longer than a crow (15 years) despite similar body sizes.

Connection Between Life Span & Reproduction

• Every organism has a limited life span, but reproduction ensures the continuity of species.
• No individual is immortal, except for some unicellular organisms like Amoeba, which divide continuously.

Would you like me to continue with Part 3: Asexual Reproduction?

BIOLOGY- REPRODUCTION IN ORGANISM LIFE SPAN Part 2.

Year Science – Botany Unit – 1 Reproduction in Organisms

CBSE Class 12 Biology – cloudfront.net

REPRODUCTION IN ORGANISMS

Chapter 2-Human Reproduction

NCERT-Class-12-Biology.pdf

Certainly! Here’s Part 2 of your Biology notes on “Reproduction in Organisms”, focusing on the Life Span concept. It’s ideal for Class 12, NEET, and foundational understanding.

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BIOLOGY – Reproduction in Organisms

Part 2: Life Span

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What is Life Span?

The life span of an organism is the period from birth to the natural death of that organism.

It is not necessarily related to size or complexity. For example, some insects may live only for a few days, while some large trees can live for thousands of years.

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Key Features of Life Span

• Every organism has a definite life span.
• Different species have different life spans.
• It does not correlate directly with body size or intelligence.

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Examples of Life Span in Various Organisms:

Organism	Approximate Life Span
Mayfly	1 day
Rice Plant	3–4 months
Dog	10–13 years
Crow	15 years
Horse	25–30 years
Elephant	60–70 years
Parrot	140 years
Tortoise	100–150 years
Banyan Tree	Over 200 years

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Important Concepts Related to Life Span

1⃣ Mortality:

• Death is the final event of the life span.
• Natural and inevitable for all living beings.

2⃣ Reproduction Phase:

• Organisms generally reproduce during the mature phase of their life span.

3⃣ Biological Immortality (Rare Cases):

• Some organisms like Hydra and Planaria show signs of regeneration and are said to be biologically immortal, though they still die due to external factors.

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NEET MCQ Practice:

Q: Which of the following organisms has the shortest life span?
A) Crow
B) Rice Plant
C) Mayfly
D) Dog

Answer: C) Mayfly

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Quick Recap:

• Life span = Birth ➝ Growth ➝ Maturity ➝ Ageing ➝ Death
• It varies greatly between species.
• Reproduction ensures continuity of species, even though individual life ends.

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Would you like:

• A visual chart of organism life spans?
• PDF revision notes for this chapter?
• Quiz or worksheet for self-practice?

Let me know, and I’ll prepare those for you!

BIOLOGY- REPRODUCTION IN ORGANISM LIFE SPAN Part 2.