Human development ( biology ) - wikipedia Human development ( biology ) `` Developmental '' redirects here. For other uses, see Development. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( January 2008 ) Part of a series on Human growth and development Stages Human embryogenesis Fetus Infant Toddler Early childhood Child Preadolescence Adolescence Adult Middle age Old age Biological milestones Fertilization Childbirth Walking Language acquisition Puberty Menopause Ageing Death Development and psychology Pre - and perinatal Infant and child Adolescent Youth Young adult Adult Maturity Developmental stage theories Attachment Ecological Psychosocial Psychosexual development Moral Cognitive Cultural - historical Evolutionary Human body portal Human development is the process of growing to maturity. In biological terms, this entails growth from a one - celled zygote to an adult human being. Contents 1 Biological development 1.1 General aspects 1.2 Physical stages 2 See also 3 Footnotes Biological development General aspects Sperm fertilizing an egg Fertilization occurs when the sperm successfully enters the ovum 's membrane. The genetical material of the sperm and egg that combine to form a single cell, called a zygote, and the germinal stage of prenatal development commences. The germinal stage refers to the time from fertilization, through the development of the early embryo, up until implantation. The germinal stage is over at about 10 days of gestation. The zygote contains a full complement of genetic material and develops into the embryo. Briefly, embryonic developments have four stages : the morula stage, the bastula stage, the gastrula stage, and the neurula stage. Prior to implantation, the embryo remains in a protein shell, the zona pellucida, and undergoes a series of cell divisions, called mitosis. A week after fertilization the embryo still has not grown in size, but hatches from the zona pellucida and adheres to the lining of the mother 's uterus. This induces a decidual reaction, wherein the uterine cells proliferate and surround the embryo thus causing it to become embedded within the uterine tissue. The embryo, meanwhile, proliferates and develops both into embryonic and extra-embryonic tissue, the latter forming the fetal membranes and the placenta. In humans, the embryo is referred to as a fetus in the later stages of prenatal development. The transition from embryo to fetus is arbitrarily defined as occurring 8 weeks after fertilization. In comparison to the embryo, the fetus has more recognizable external features and a set of progressively developing internal organs. A nearly identical process occurs in other species. Physical stages The following are some approximate age ranges for physical development stages : Stages in prenatal development. Prenatal ( sperm fertilizes egg -- birth ) Embryo ( fertilization -- 8 weeks after fertilization ) Zygote, the single cell stage which occurs after fertilization Blastocyst, the stage prior to implantation, when the embryo is a hollow sphere Post-implantation embryo, the period 1 -- 8 weeks after fertilization ( 3 to 10 weeks ' gestation ) Fetus, ( 10th week of pregnancy -- birth ) Approximate outline of development periods in child development. Further information : Child development and Child development stages Female height vs Age ( US CDC ) Male height vs Age ( US CDC ) Childhood / Juvenile ( Childbirth ) ( 0 -- 5 ) Neonate ( newborn ) ( 0 -- 28 days ) Infant ( baby ) ( 1 month -- 12 months ) Toddler ( 1 -- 2 years ) Play age ( 3 -- 5 years ) Primary school age ( middle childhood also called prepubescence ) ( 6 -- 11 ) Elementary school age ( 6 -- 8 ) Preadolescence ( The child in this and the previous phase are called schoolchild ( schoolboy or schoolgirl ), when still of primary school age. ) ( 9 -- 11 years ) Adolescence ( 12 -- 18 years ) Peripuberty ( 8 -- 12 ) Puberty ( 13 -- 17 ) Adulthood ( 19 + years ) Young adulthood ( 19 -- 39 years ) Middle adulthood ( 40 -- 60 years ) Elder / Senior citizen ( 60 + years ) Death ( unpredictable ) Decomposition ( breakdown of the body after death ) Also sometimes used are terms that specify one 's age in numbers, such as : Baby ( 0 ) Toddler ( 1 -- 2 ) Preschooler ( 3 -- 4 ) Main childhood ( 5 -- 9 ) Pre-teenager ( 10 -- 12 ) Teenager ( 13 -- 19 ) Twentysomething ( 20 -- 29 ) Thirtysomething ( 30 -- 39 ) Fortysomething ( 40 -- 49 ) Fiftysomething ( 50 -- 59 ) Sixtysomething ( 60 -- 69 ) Seventysomething ( 70 -- 79 ) Eightysomething ( 80 -- 89 ) Ninetysomething ( 90 -- 99 ) Centenarian ( 100 -- 109 ) Supercentenarian ( 110 + ) The Tanner stages can be used to approximately judge a child 's age based on physical development. See also Auxology Child development Developmental biology Embryogenesis Life - history theory Footnotes Jump up ^ Sherk, Stephanie Dionne. `` http://www.healthline.com/galecontent/prenatal-development ''. Gale Encyclopedia of Children 's Health, 2006. Gale. Archived from the original on 1 December 2013. Retrieved 6 October 2013. External link in title = ( help ) Jump up ^ `` germinal stage ''. Mosby 's Medical Dictionary, 8th edition. Elsevier. Retrieved 6 October 2013. Human biological and psychological development Before birth Embryo Fetus After birth Infant Toddler Early childhood Childhood Child Preadolescence Adolescence Adulthood Middle age Old age Definitions Minor Age of majority Events and phases Gestational age Prenatal development Birth Child development stages Cognitive development of infants Human development Adult development Puberty Ageing Senescence Death Developmental psychology Antenatal Positive youth development Young adult Positive adult development Maturity Theorists and theories Freud ( 1856 -- 1939 ) ( Psychosexual development ) Piaget ( 1896 -- 1980 ) ( Theory of cognitive development ) Vygotsky ( 1896 -- 1934 ) ( Cultural - historical psychology ) Erikson ( 1902 -- 1994 ) ( Psychosocial development ) Bowlby ( 1907 -- 1990 ) ( Attachment theory ) Bronfenbrenner ( 1917 -- 2005 ) ( Ecological systems theory ) Kohlberg ( 1927 -- 1987 ) ( Stages of moral development ) Commons ( b. 1939 ), Fischer ( b. 1943 ), Kegan ( b. 1946 ), Demetriou ( b. 1950 ), and others ( Neo-Piagetian theories of cognitive development ) Evolutionary developmental psychology Human embryogenesis in the first three weeks Week 1 Fertilization Oocyte activation Zygote Cleavage Blastomere Morula Blastocoele Blastocyst Blastula Inner cell mass Trophoblast Week 2 ( Bilaminar ) Hypoblast Epiblast Week 3 ( Trilaminar ) Germ layers Archenteron / Primitive streak Primitive pit Primitive knot / Blastopore Primitive groove Gastrula Gastrulation Regional specification Embryonic disc Ectoderm Surface ectoderm Neuroectoderm Somatopleuric mesenchyme Neurulation Neural crest Endoderm Splanchnopleuric mesenchyme Mesoderm Axial mesoderm Paraxial Somite Somitomere Intermediate Lateral plate Intraembryonic coelom Splanchnopleuric mesenchyme Somatopleuric mesenchyme Retrieved from `` https://en.wikipedia.org/w/index.php?title=Human_development_(biology)&oldid=826797065 '' Categories : Human development Humans Developmental psychology Hidden categories : CS1 errors : external links Articles needing additional references from January 2008 All articles needing additional references Talk Contents About Wikipedia Asturianu Bosanski Čeština Español فارسی Français Galego हिन्दी Italiano עברית Қазақша Kiswahili Nederlands नेपाल भाषा Polski Русский Српски / srpski Srpskohrvatski / српскохрватски Українська 中文 Edit links This page was last edited on 21 February 2018, at 01 : 43. 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Question: what are the four stages of human development
Answer: morula