SEXUAL AND ASEXUAL METHODS OF REPRODUCTION
ANIMALS: ADVANTAGES OF EXTERNAL AND INTERNAL FERTILISATION
FUNGI, BACTERIA AND PROTISTS
PLANTS: ASEXUAL AND SEXUAL REPRODUCTION
EXTERNAL
INTERNAL
Results in the production of a large number of zygotes
Easier to locate mates as the gametes released can drift due to environmental conditions e.g. wind, water
More genetic variation
Increased possibilities of unions of gamete because all conditions required for fusion of gametes is maintained inside the body
More protection against outside environments and predators, and therefore a higher chance of surviving until birth
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Corals, for example, release large amounts of gametes at the same time in the hope that some will be fertilised and then survive to adulthood.
More selective of mates
SEXUAL
ASEXUAL
MALE GAMETES REQUIRED
FERTILISATION
GERMINATION
POLLINATION
transferring pollen grains from the male anther of a flower to the female stigma
the sperm cell that was transferred by the pollen tube fuses with the egg cell inside the ovule in the female part of the flower.
if the seed lands in suitable soil that provides sufficient water, oxygen, and warmth, it germinates
the embryo begins to grow, producing a radicle or young root to absorb water and soil nutrients, as well as a plumule or young stem, which develops green leaves for food production by photosynthesis.
DOES NOT INVOLVE GAMETES
Vegetative Propagation
New individuals arising from portions of the roots, stems, leaves or buds of adult individuals and being genetically identical to their parent.
GRAFTING
LAYERING
CUTTING
Stem from the plant is cut and is planted in the soil that will gradually grow and turn into another plant.
Used for plants like rose, hibiscus, sugarcane
A branch from the whole plant is selected, bent and the bent portion is covered with soil while still being attached to the mother plant
The bent portion touching the soil develops roots and the part above the ground develops into individual plants.
Two different plants are selected and joined so that they grow as one single plant. One of the plants serves the purpose of being grounded by root formation which is termed as the stock.
BINARY FISSION (BACTERIA AND PROTISTS)
SPORES (FUNGI)
BUDDING (FUNGI AND PROTISTS)
Type of asexual reproduction in which a new organism is formed from a bud of an existing organism. The new organism remains attached to the parent organism till it gets matured. Organisms like Hydra and yeast reproduce by budding.
Asexual reproduction by a separation of the body into two new bodies. In the process of binary fission, an organism duplicates its genetic material, or DNA, and then divides into two parts, with each new organism receiving one copy of DNA.
A reproductive cell capable of developing into a new individual without fusion with another reproductive cell