(a) Why is it not possible to reconstruct the whole organism from a fragment in complex multicellular organisms?
(b) Sexual maturation of reproductive tissues and organs are necessary link for reproduction. Elucidate.
- Many multi-cellular organisms are not simply a random collection of cells.
- Specialised cells are organised as tissues , and tissues are organised into organs , organised into organ systems , which then are placed at definite positions in the body.
- Therefore, cell-by-cell division (which is asexual) to form different types of cells with different structures and functions would be impractical .
Sexual maturation of reproductive tissues is a necessary link for reproduction.
- This is because of the need for germ-cells to participate in sexual reproduction .
- The germ-cells are produced only in mature reproductive tissues .
- The body of the individual organism has to grow to its adult size .
- When the rate of general body growth begins to slow down , reproductive tissues begin to mature.
The maturation of these tissues leads to changes in the appearance of the body like change in body proportions and appearance of new features .
- This period during adolescence is called puberty .
- There are also changes taking place that are different between boys and girls .
- In girls, breast size begins to increase , with darkening of the skin of the nipples.
- Girls also begin to menstruate during puberty.
- Boys begin to have new thick hair growth on the face and pubic regions and their voices begin to crack .