REPRODUCTION IN ORGANISMS
IMPORTANT TERMS:
· · Clone: Population of genetically identical individuals.
·
Gestation
Period: The time from conception to birth.
·
Life
span:
The period from birth to death of an organism.
·
Parthenogenesis:
Development of an egg (female gamete) into a complete individual without
fertilization by a sperm (male gamete).
·
Reproduction:
A
biological process in which an organism gives rise to young ones (offspring)
similar to itself.
·
Senescence:
The period between reproductive maturity and death.
·
Syngamy:
Refers to the fusion of gametes.
·
Slips:
Small pieces or plantlets, which can be removed and used for propagation.
·
Scion:
Part of the plant (a twig or a bud) that is grafted on the stock.
·
Stock:
Part of the plant that provides support and the root system.
·
Vegetative
Propagation: The process of multiplication in which
portions or fragments of the plant body function as propagules and develop into
new individuals.
ADDITIONAL INFORMATION:
· Reproductive Roots:
The roots which bear adventitious buds and help in multiplication of plants.
·
Time
for Horticultural Propagation: Rainy season and
spring season.
·
Sexual
Reproduction in plants: First studied by Camerarius (1694).
·
Twins
(i) Fraternal Twins (dizygotic or non identical twins):
Two offspring that have developed
in the uterus at the same time but are the result of independent fertilization
of two ovary.(ii) Monozygotic Twins (identical twins). Two offspring developed
from a single fertilized ovum. At an
early stage the zygote (fertilized ovum) separates into two independent cells that develop into offspring of the
same sex with identical genetic characteristics. (iii) Siamese Twins (United Twins). Twins
jointed in a small area. Named after Chang
and Eng born in Siam
(Thailand). Their parents were Chinese. Now modern surgical techniques have
made it possible to separate
Siamese infants.
·
Wilmut
Clone Dolly (a sheep) the world’s first cloned
mammal in 1997.
·
The desert –grassland Whiptail lizard (Cnenidophorus uniparens) an all female
species. There are no males. It
reproduces by parthenogenesis.
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