Evolution
Chapter Name : Heredity And Evolution |
Sub Topic Code : 103_10_09_03_01 |
Topic Name : Evolution |
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Sub Topic Name : An Illustration |
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Introduction
We have seen that there is a natural tendency of variation in sexual reproduction, in this topic we see through an illustration which variations survive and which don’t.
Pre-Requisites:
What is evolution?
Activity:
Observe what colour creatures are found in dessert, bushes and in or near snowy places. To observe natural selection
Real Life Question:
What coloured beetles are likely to survive in green bushes – green, blue or red?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Natural Selection Genetic Drift | When a variation becomes common since it gave a survival advantage, the variation is said to be naturally selected. Change in frequency of a variation, which provides diversity without adaptations. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Go through fig. 9.7 in NCERT. | Look at the illustration |
Places to visit :
Bushes, dessert, hill station.
Practical examples around us
| Examples | Explainations |
|---|---|
| Polar bears are white in colour, in snowy regions brown coloured bears are not found. |
What you learn in Theory:
Natural selection and genetic drift are important components of evolution.
What you learn in Practice:
Survival of the fittest – those that fit in an environment have more chances of survival.