Reproduction Reproduction # The importance of reproduction is to ensures that a particular species does not extinct !!!#

4.1 sexual and asexual

reproduction� Reproduction =

involves the production of new generation of individuals of same species.

� Sexual reproduction

involve male and female organisms.

� Asexual reproduction

involves only one parent.

Asexual reproduction�� Binary fission Binary fission (unicellular organism divides into two equal parts

(daughter cells)

�� BuddingBudding (the parent produces an outgrowth or bud which detaches

to become a new individual)to become a new individual)

�� Spore formationSpore formation

�� Vegetative reproductionVegetative reproduction

�� Regeneration Regeneration (Regrowth of lost or destroyed parts or organs)

Binary fission

Vegetative reproduction � This type of asexual reproduction is seen in many

flowering plants.

� Part of a plant detaches and grow into a new plant.

� Example: � Example:

i. Runner

ii. Bulb

iii. Rhizome

iv. Corm

v. Stem tuber

i. Runner � A slender, creeping stem that puts forth roots from

nodes spaced at intervals along its length.

� The runner bears roots and becomes independent before the parent plant die.before the parent plant die.

� Example : grass, strawberry

ii. Bulb � A short, modified, underground stem surrounded by

usually fleshy modified leaves that contain stored food for the shoot within.

� Example : Onion, lilies � Example : Onion, lilies

iii. Rhizome � A horizontal, usually underground stem that often

sends out roots and shoots from its nodes.

� Example: ginger, Canna

iv. Corm � A short, thick, solid, food-storing underground stem,

sometimes bearing papery scale leaves.

� Examples: cocoyam , water chestnut

iv. Stem tuber � The swollen ends of underground stems

� New shoot sprout out from axillary buds or ‘eyes’.

� Example: potato, beet

4.2 The male reproductive system

Secondary sexual characteristics

( male) � Growth of hair on face, chest, in pubic region and

armpits.

Beard Moustache

� The voice becomes deeper.

� Body becomes more muscular.

� Chest becomes broader.

� Certain mental and emotional changes.

Male gamete (sperm)� The role of the

sperm is to swim towards the ovum and the ovum and fuses with it to form zygote.

� Zygote will develop into an adult individual.

4.3 The female reproductive

system

Female gamete (ovum)

� The ovum stores some food in its cytoplasm.

� The food is used to nourish the embryo which develops from the zygote.

Secondary sexual characteristics

( female) � Growth of hair in pubic region and armpits.

� Commencement of menstruation.

� Production of ova by the ovaries.

Pelvis becomes broader.� Pelvis becomes broader.

� Fat deposits on hip and thighs.

� Growth and development of breasts.

� Certain mental and emotional changes.

4.4 The menstrual cycleMenstruation is the

discharge of the uterus lining and blood through the blood through the vagina.

What happen after sexual

intercourse ? � Sperms swing to

Fallopian tube.

� Only one sperm one sperm is needed to fertilise the needed to fertilise the ovum.

� Sperm and ovum fuse to form zygote.

� The zygote form a ball of cell called embryo.

Fertilisation� Fertilisation =

The union of male and female gametes to form a zygote.zygote.

Growth and development of the

foetus in uterus (womb)

Exchange of materials in placenta

New baby

Importance of pre-natal care 1. Diet

Advice: Eat a good healthy diet rich in proteins, calcium and vitamins.

Importance of pre-natal care 2. Cigarette smoke

Importance of pre-natal care 3. Avoid alcohol and drugs