Human development (biology)

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Life
- Prenatal (fertilisation - birth)
  - Embryo - (fertilisation - 8 weeks of gestational phase)
  - Foetus (8 weeks of gestational phase - birth)
- Child (birth - age of majority)
  - Infancy (birth - walking age)
  - Toddlerhood (walking age - 3 years)
  - Early childhood (3 - 7 years)
  - Preadolescence (7 years - puberty, with the exception of precocious puberty)
  - Adolescence (puberty - age of majority)
- Adult (age of majority - death)
  - Young adult (age of majority - 40 years)
  - Middle age (40 - 55 years)
  - Advanced adult/Senior citizen/Old age (55 years - death)
Death
- Decomposition (breakdown of the body after death)

Also sometimes used are terms that specify one's age in numbers, such as:

Child (0-12)
Teenager (13-19)
Twentysomething (20-29)
Thirtysomething (30-39)
Fortysomething (40-49) (formerly also Quadragenarian, rarely used since 1980)
Quinquagenarian (50-59)
Sexagenarian (60-69)
Septuagenarian (70-79)
Octogenarian (80-89)
Nonagenarian (90-99)
Centenarian (100-109)
Supercentenarian (110+)

[edit] Physical development milestones

Ability to lift and control the orientation of the head
Crawling begins
Walking begins
Speech begins
Voice lowers in pitch (especially noticeable in boys)
Pubic hair appears
Genitals and reproductive organs mature
Menses begin (females)
Body hair and facial hair appears

Note: the Tanner stages can be used to approximately judge a child's age based on physical development.

[edit] See also

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v • d • e Human topics
Anatomy • Appearance • Art • Behavior • Biology • Civilization • Communication • Condition • Culture • Development • Evolution • Genetics • Health • Mind • Nature • Rights • Sexuality • Society • Technology

v • d • e Human development: biological - psychological
Stages	Infancy • Childhood • Preadolescence • Adolescence • Adulthood - Early adulthood • Middle adulthood • Late adulthood
Development	Child development • Youth development • Ageing & Senescence
Theorists-theories	John Bowlby-attachment • Erik Erikson-psychosocial • Sigmund Freud-psychosexual • Lawrence Kohlberg-moral • Jean Piaget-cognitive • Lev Vygotsky-cultural-historical

v • d • e Developmental biology > Human embryogenesis (development of embryo) and development of fetus (some dates are approximate - see Carnegie stages and a timeline)
Week 1	Fertilization - Egg activation - Zygote - Cleavage - Morula - Blastula (Blastomere) - Blastocyst - Inner cell mass
Week 2	Bilaminar disc (Hypoblast, Epiblast)
Week 3 (Trilaminar embryo, germ layers)	Archenteron/Primitive streak (Primitive pit, Primitive knot/Blastopore, Primitive groove) - Gastrula/Gastrulation - Regional specification Ectoderm: Surface ectoderm - Neuroectoderm - Somatopleure - Neurulation - Neural crest Endoderm: Splanchnopleure Mesoderm: Chorda- - Paraxial (Somite/Somitomere/Sclerotome/Myotome/Dermatome) - Intermediate - Lateral plate (Intraembryonic coelom, Splanchnopleure/Somatopleure)
Extraembryonic/uterus	Trophoblast (Cytotrophoblast, Syncytiotrophoblast) Blastocoele - Yolk sack/exocoelomic cavity - Heuser's membrane - Extraembryonic coelom - Vitelline duct Umbilical cord (Umbilical artery, Umbilical vein, Wharton's jelly) - Allantois Placenta - Decidua (Decidual cells) - Chorionic villi/Intervillous space - Gestational sac (Amnion/Amniotic sac/Amniotic cavity, Chorion)
Histogenesis	Programmed cell death - Stem cells - Germ line development
Organogenesis	Limb development: Limb bud - Apical ectodermal ridge/AER - Eye development - Cutaneous structure development - Heart development - Development of the urinary and reproductive organs