Formation of Twins

 

 
15.5

Formation of Twins

 
 
Types of twins Identical twins 
Fertilisation 1 ovum fertilised by 1 sperm
Zygote formation Formed from 1 zygote
Placenta Share one placenta but have their own umbilical cord
Embryo division Divide into two
Umbilical cords 2
Gender Same sex
Genetic constitution Identical
Physical characteristics Identical
Fingerprints Unique (different)
 
 
Types of twins Siamese twins
Fertilisation 1 ovum fertilised by 1 sperm
Zygote formation Formed from 1 zygote
Placenta Share one placenta but have their own umbilical cors
Embryo division Incomplete division
Umbilical cords 2
Gender Same sex
Genetic constitution Identical
Physical characteristics Identical
Fingerprints Unique (different)
 
 
Types of twins Fraternal twins
Fertilisation 2 ovum fertilised by 2 sperm
Zygote formation Formed from 2 different zygote
Placenta Each has their own placenta and umbilical cords
Embryo division Not divide into two
Umbilical cords 2
Gender Same/different sex
Genetic constitution Different
Physical characteristics Different
Fingerprints Unique (different)
 

 

Formation of Twins

 

 
15.5

Formation of Twins

 
 
Types of twins Identical twins 
Fertilisation 1 ovum fertilised by 1 sperm
Zygote formation Formed from 1 zygote
Placenta Share one placenta but have their own umbilical cord
Embryo division Divide into two
Umbilical cords 2
Gender Same sex
Genetic constitution Identical
Physical characteristics Identical
Fingerprints Unique (different)
 
 
Types of twins Siamese twins
Fertilisation 1 ovum fertilised by 1 sperm
Zygote formation Formed from 1 zygote
Placenta Share one placenta but have their own umbilical cors
Embryo division Incomplete division
Umbilical cords 2
Gender Same sex
Genetic constitution Identical
Physical characteristics Identical
Fingerprints Unique (different)
 
 
Types of twins Fraternal twins
Fertilisation 2 ovum fertilised by 2 sperm
Zygote formation Formed from 2 different zygote
Placenta Each has their own placenta and umbilical cords
Embryo division Not divide into two
Umbilical cords 2
Gender Same/different sex
Genetic constitution Different
Physical characteristics Different
Fingerprints Unique (different)