Heterochrony (hetro = different and chrony = time scale)
Different developmental processes accelerate or retard (vertragen) relative to each
other
o Neoteny: somatic development (development of the body itself) is retarded,
sexual development continues normally
o Paedomorphosis: somatic development is stopped abruptly, sexual
development continues normally
o Progenesis: reproductive development is greatly accelerated
o Peramorphosis: somatic development is accelerated
Neoteny
Baby chimpanzees has not yet the prognathic face while the adult
chimpanzee has developed the prognathic face
Neotenic traits in the skull
Orhognathic face (tegenovergestelde van proganathic face), high vault of skull roof,
large rounded eye sockets, slight torus supraorbitalis (bot bij wenkbrauwen) , light
glabella (schedel dat zich tussen de wenkbrauwen bevindt), thin skull bones, small
jaws
Females more neotenic (feminity)
Males more non-neotenic (more like chimpanzee) (masuculine)
This has to do with sexual dimorphism (condition where the 2
sexes of the same species exhibit different characteristics
beyond the differences in their sexual organs)
o Glabella more deep in the male
o Supraorbitalis more heavy in male
o Occipital ridges are stronger in male because they
determine the attachment side of the neck muscle
o Eye socket more round in female and more square in males
o Angle of mandible (kin) round in females and protrudes (steekt uit) in male
o Mentum (onderste kaak) outstanding in male
Neoteny in the brain
When baby is born brain is not fully developed this (hardly any instinctual behaviours)
will be around 24/25 years
This allows flexibility and learning – from parents we can learn
When we are born we know how to reproduce and how to eat!
Neoteny in the life-cycle
The total lifespan is increased but also the length of juvenile (jeugd)
period – the life-cycle is estimate from fossil tooth
Adolescence: age interval between puberty and birth of first child (start
around (12-14 age) and end around (28-32 age)
Back in the days women have earlier children than nowadays so this is
neoteny
Different developmental processes accelerate or retard (vertragen) relative to each
other
o Neoteny: somatic development (development of the body itself) is retarded,
sexual development continues normally
o Paedomorphosis: somatic development is stopped abruptly, sexual
development continues normally
o Progenesis: reproductive development is greatly accelerated
o Peramorphosis: somatic development is accelerated
Neoteny
Baby chimpanzees has not yet the prognathic face while the adult
chimpanzee has developed the prognathic face
Neotenic traits in the skull
Orhognathic face (tegenovergestelde van proganathic face), high vault of skull roof,
large rounded eye sockets, slight torus supraorbitalis (bot bij wenkbrauwen) , light
glabella (schedel dat zich tussen de wenkbrauwen bevindt), thin skull bones, small
jaws
Females more neotenic (feminity)
Males more non-neotenic (more like chimpanzee) (masuculine)
This has to do with sexual dimorphism (condition where the 2
sexes of the same species exhibit different characteristics
beyond the differences in their sexual organs)
o Glabella more deep in the male
o Supraorbitalis more heavy in male
o Occipital ridges are stronger in male because they
determine the attachment side of the neck muscle
o Eye socket more round in female and more square in males
o Angle of mandible (kin) round in females and protrudes (steekt uit) in male
o Mentum (onderste kaak) outstanding in male
Neoteny in the brain
When baby is born brain is not fully developed this (hardly any instinctual behaviours)
will be around 24/25 years
This allows flexibility and learning – from parents we can learn
When we are born we know how to reproduce and how to eat!
Neoteny in the life-cycle
The total lifespan is increased but also the length of juvenile (jeugd)
period – the life-cycle is estimate from fossil tooth
Adolescence: age interval between puberty and birth of first child (start
around (12-14 age) and end around (28-32 age)
Back in the days women have earlier children than nowadays so this is
neoteny
