Heredity
Important Definitions
Heredity- Transmission of characters from one generation to the next generation
Characters- Properties of an organism that are visibly expressed
Traits- Variations/ different types of a character
Eg: Violet and white flowers in pea plant
Importance of Variations
Not essential for organism, but important for survival of species
All organisms possess a well defined space in the environment known as niche
All organisms have adapted themselves to their niche
However, sometimes niches can change due to various environmental factors such as global warming, meteorite hits, etc.
Organisms might not be adapted to these changes in the niche and hence the population can be wiped out
Only those organisms who have variations that allow them to survive will pertain and thus this variation shall also be present in future gens
How Variations
Environmental Factors (Changes in niche)
Reproduction
Variations occur due to small errors in DNA copying
Minimum in asexual reproduction but maximum in sexual reproduction
More chance in sexual reproduction due to :- 1) Exchange of DNA segs during crossing over in gamete formation and 2) Union of traits from two parents during fertilisation
Traits
Inherited
Transferred from 1 generation to the next generation
Determined by genes of an individual
Eg: Body Colour, eye colour
Acquired
Simply acquired during the lifetime of an individual
Not transferred to future generations as it doesn't affect the genes
Eg: Surgical removal of a mouse's tail will not mean future gens will have no tail