REPRODUCTION IN ORGANISMS : REPRODUCTION IN ORGANISMS Copyright
© BBIPL
Slide 2 : BIRTH
Juvenility (animals)
or
Vegetative phase (plants)
Maturity
or
Reproductive phase
Ageing
(Senescence)
DEATH Life Span
of an organism
Life Span of certain organisms : Life Span of certain organisms Larrea tridentata 11300 years
Sequoia 3000-4000
Banyan tree 200
Tortoise 200
Human 120
Eagle 90
Elephant 70 Monkey 26
Dog 22
Tiger 22
Rat 5
Bee 1-5
Mayfly One day
Microorganisms Min. to Hours
What is Reproduction ? : What is Reproduction ? Biological Process
To produce again and like-wise
Why to reproduce ? : Why to reproduce ? To increase number (Population)
Continue the species
Important steps (features) of Reproduction : Important steps (features) of Reproduction RNA and PROTEIN synthesis
DNA replication
Cell division
Formation of Reproductive Units (bodies)
Slide 7 : Reproduction
The Continuity of Life
Two basic reproductive modes : Two basic reproductive modes Asexual reproduction
Requires only one parent
Offspring are genetically identical to parent and to each other
Sexual reproduction
Requires meiotic cell division in two parents
Produces genetically variable offspring, with different combinations of parental genes
ASEXUAL REPRODUCTION : ASEXUAL REPRODUCTION A single parent produces offsprings
Identical offsprings produced (Clones)
That is, MORPHOLOGICALLY & GENETICALLY SIMILAR
NO gametes / no fertilization
Mitotic divisions only
RAPID/NO VARIATIONS/NOT EVOLUTIONARY
ASEXUAL REPRODUCTION : ASEXUAL REPRODUCTION Common and widespread in ….
- SINGLE CELLED ORGANISMS
- PLANTS
- ANIMALS
Asexual methods of reproduction : Asexual methods of reproduction FISSION - Binary
- Longitudinal
- Multiple
SPORE FORMATION
BUDDING - External
- Internal
FRAGMENTATION
VEGETATIVE PROPAGATION
PARTHENOGENESIS
Binary fission in Amoeba : Binary fission in Amoeba
Binary fission in bacteria : Binary fission in bacteria
Longitudinal binary fission in Euglea (Symmetrogenic) : Longitudinal binary fission in Euglea (Symmetrogenic)
Homothetogenic binary fission in Paramecium : Homothetogenic binary fission in Paramecium
Transverse binary fission in Paramecium : Transverse binary fission in Paramecium
Binary fission leads to daughter paramecia : Binary fission leads to daughter paramecia
Binary fission in Planaria : Binary fission in Planaria
Slide 19 :
External budding in Yeast : External budding in Yeast
Asexual Reproduction : Asexual Reproduction 3. Budding
Occurs in Hydra and yeast.
The division of cytoplasm is unequal so one of the daughter cells is larger than the other.
The daughter cells can separate or remain attached.
Psuedomycellium of yeast : Psuedomycellium of yeast Chain of buds Also External budding in Poriferans
Internal budding in Sponges (fresh water) : Internal budding in Sponges (fresh water) Gemmules of Spongilla
How Hydra forms buds ? : How Hydra forms buds ?
Asexual reproduction: budding : Asexual reproduction: budding Adult Bud Miniature animal begins as a bud on an adult, then becomes independent Budding in Hydra
Asexual Reproduction : Asexual Reproduction Sporulation
Occurs in molds, mosses, etc
Spores are produced in large numbers by mitosis.
Spores are surrounded by a tough coat to help them survive harsh environmental conditions.
Asexual reproduction : Asexual reproduction Fission in asea anemone
Fragmentation in Sea star : Fragmentation in Planaria Asexual reproduction : By regeneration Fragmentation in Sea star
Slide 29 : Flatworm cut into two Posterior half with no head Grows new head Anterior half
with no tail Grows new tail
A memorable example : A memorable example Star fishes and regeneration
Some fishermen (USA) wanted to prevent
Starfishes from destroying their oysters (beds)
They collected many starfishes and chopped them and threw them into the sea.
Starfishes regenerated from small pieces and
caused POPULATION EXPLOSION
A bad move by fishermen.
SPORE FORMATION : SPORE FORMATION Asexual structures
ZOOSPORES (Microsporic, flagellated)
CONIDIA
Slide 32 :
Vegetative propagation : Vegetative propagation Through the structures called vegetative propagules
Two parents are NOT involved
Mostly the term used in plants
Leads to clones
Structures (propagules) involved include :
* Offset
* Eye Buds
* Rhizome
* Bulbils
* Leaf buds
Offset of water hyacinth (Terror of Bengal) : Offset of water hyacinth (Terror of Bengal)