Growth and Development
Growth : it is the increase in the number of cells. It is a permanent increase in size. (Do you think that getting fat can also be called growth?). Growth refers to features that can be measured, example: 1. Increase in mass: dry or wet mass of a plant (Growth or not? A seed in water increase in mass) 2. Increase in height: e.g. human height, height of plant shoot 3. Increase in surface area: e.g. leaves ( note: puffer fish increase in size to scare predators, is this called growth?) 4. Increase in numbers: e.g. increase in number of leaves Growth can be divided into three stages: (a) cell division (b) cell enlargement (c) cell differentiation Growth in humans: Stages (a) Infancy and childhood: Rapid development in height. Cell division takes place in all parts of body by mitosis (b) Puberty: Stage of sexual maturity. Growth continues until adulthood, with increase in height more rapid than increase of weight. (c) Adulthood: Most adult stop gro