Medium of gamete transfer : Medium of gamete transfer WATER
Male gamete need water
Eg. Algae
Bryophytes
Peridophytes
Corals
Fishes
frogs
Frog spawn : Frog spawn Coral spawning
POLLENS : POLLENS Carriers male gametes
By POLLLINATION Self or Cross
BODY FLUID : BODY FLUID Carried in a nutrient fluid
Semen in humans through sexual contact (mating)
EXTERNAL FERTILIZATION : EXTERNAL FERTILIZATION Organisms shows great SYNCHRONY between the sexes
Eg.- Frogs ( male and female) breed in rainy season
External fertilization : Amplexus : External fertilization : Amplexus Male frogs mount females in a pose called amplexus
Female releases eggs and male then releases a cloud of sperm over them
In plants, pollens and ova develop at the same time : In plants, pollens and ova develop at the same time Pollen germinating pollen
Pollens and ovules develop together : Pollens and ovules develop together
How ovule develop ? : How ovule develop ?
Slide 10 : Large number of gametes are released (to enhance the chances of fertilization).
External fertilization is a disadvantage as it is prone to predators/environment change
External fertilization in Fishes. : External fertilization in Fishes. The female deposits her eggs and the male
Follows behind releasing millions of sperm.
Most animals are dioecious, with separate females and males : Females produce large, non-motile eggs, that contain food reserves
Males produce small, motile sperm, with no food reserves Most animals are dioecious, with separate females and males
External fertilization: Spawning : External fertilization: Spawning Union of sperm and egg takes place outside the bodies of the parents
External fertilization is common in animals that live in water
Release of sperm and eggs into the water is called spawning
Release is often synchronized using environmental cues (e.g., seasons, tides)
Internal Fertilization in Rafflesia : Internal Fertilization in Rafflesia Flowers (largest flower- 1m and 7 Kg)
They smell of rotting meat which attracts caryon flies for pollinating.
Rhizanthes flowers pollinated by carrion flies : Rhizanthes flowers pollinated by carrion flies Internal Fertilization
Internal fertilization in Maize : Internal fertilization in Maize Huge tassels are amongst the largest are stigmas in plant kingdom
Most animals are dioecious, with separate females and males : Most animals are dioecious, with separate females and males Female mallard Male mallard
Slide 19 : INTERNAL FERTILIZATION Mating introduces sperm directly into the body of the female.
Males and females are extremely different in their appearance or behavior = sexual dimorphism : Males and females are extremely different in their appearance or behavior = sexual dimorphism
Slide 21 : Important adaptation to life on land
Fertilization occurs inside female’s body
Copulation: Male deposits sperm directly into female’s reproductive tract INTERNAL FERTILIZATION = In vivo
The human egg : The human egg
Mr. Sperm and Ms. Egg meeting : Mr. Sperm and Ms. Egg meeting
Slide 25 : OVOPAROUS + OVOVIVIPAROUS ………….Egg laying
VIVIPAROUS
………….Body born
OVIPAROUS (Egg-Birth) : OVIPAROUS (Egg-Birth) Fertilization is External
Development is external
Eggs are laid (unfertilized)
Eg- Pisces (fishes)
Amphibians
Most invertebrates
Sponge spawning : Sponge spawning
Coral spawning : Coral spawning
Slide 30 : Frog spawn
Fish spawning (Sturgeon) : Fish spawning (Sturgeon)
OVOVIVIPAROUS (Egg-living-birth) : OVOVIVIPAROUS (Egg-living-birth) Fertilization is Internal
Development is Internal
Eggs laid (fertilized)
Eg.- Gastropods (molluscs)
Annelids (few)
Brachiopods; insects
Some fishes & reptiles & birds
Egg-laying mammals (Prototherians)
Egg of a Dinosaur : Egg of a Dinosaur
Further developed embryo of a chick : Further developed embryo of a chick
Ovoviviparous snakes….produce eggs : Ovoviviparous snakes….produce eggs
VIVIPAROUS (Live birth) : VIVIPAROUS (Live birth) Fertilization is Internal
Development is Internal
Babies are born
Eg. Most mammals
Elasmobranch
Scorpions
Snakes (few)