Aphids giving babies parthenogenetically : Aphids giving babies parthenogenetically Leaf insects reproduce parthenogenetically
EXCEPTIONAL : EXCEPTIONAL Some trees/plants flower during the same month year after year (seasonal)
Eg. Mango, Apple , Jackfruit
Slide 3 : Some plants flower throughout the year
Others show unusual flowering phenomena
Bamboo sp. flower once in
50-100yrs
Neel kuranji (Strobilanthus Kunthiana) flower once in 12 Years : Neel kuranji (Strobilanthus Kunthiana) flower once in 12 Years Last time….Aug-Dec, 2006
Small BLUE flowering plants
Blooms over SHOLA GRASSLANDS of Western Ghats (1800m)
Slide 5 : All of them seed together to escape from predators.
The phenomenon is called ‘Predator satiation’
Next bloom would be in 2018
NEEL KURINJI : NEEL KURINJI Found mainly in Kerala, Tamil Nadu and Karnataka.
These are ENDANGERED
Seasonal animal breeders : Seasonal animal breeders Eg. Frogs, fishes, Birds
They reproduce in favourable periods
Seasonal breeders…birds : Seasonal breeders…birds
Continuous animal breeders : Continuous animal breeders Eg. Mammals
They reproduce throughout in their reproductive phase
Excetions… : Excetions… Birds in captivity (poultry farms) can be made to lay eggs throughout the year.
Cyclical changes (in mammals) : Cyclical changes (in mammals) Oestrus cycle in NON PRIMATES
Cows, sheep, rats, deers, dogs, tigers..
Menstrual cycle in PRIMATES
Monkeys, apes, humans
Amongst mammals some are seasonal breeders
Eg. dogs.
Events in Sexual Reproduction : Events in Sexual Reproduction Gametogenesis
Gamete transfer
Fertilization
Zygote formation
Embryogenesis Pre fertilization Events Post-fertilization Events
GAMETOGENESIS : GAMETOGENESIS Formation of male and female gametes
That is, HAPLOID CELLS.
These gametes could be :
Homogametic Heterogametic
Both gametes are similar Gametes are in appearance morphologically dissimilar.
Also called ISOGAMETES Male gamete is also
Eg. Some algae called ANTHEROZOID or SPERM
Isogametes of cladophora (algae) Female gamete is called the EGG or OVUM
Eg. Most organism
Isogamy : Isogamy
Homogamy orIsogamy in Spirogyra : Homogamy orIsogamy in Spirogyra
Herterogamy = Gametes are morphologically dissimilar : Herterogamy = Gametes are morphologically dissimilar
Sexuality in Organisms : Sexuality in Organisms CROSS FERTILIZATION ( = EXOGAMY)
Fusion of gametes from two different individuals
Shown by Unisexuals, ie they have reproductive structures on different plants or animals
Cross fertilization : Cross fertilization
Sexuality in Organisms : Sexuality in Organisms Unisexual individuals (or conditions) are also called
Dioecious or Heterothallic
Eg- Date palm
Papaya
Insects
Man
Birds
Repliles - Plants - Animals
Papaya : Papaya Dioecious plants