what are the four stages of human development
Human development (biology) 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.
Zone of proximal development One example of children using ZPD is when they are learning to speak. As their speech develops, it influences the way the child thinks, which in turn also influences the child's manner of speaking.[8] Wells gives the example of dancing: when a person is learning how to dance, they look to others around them on the dance floor and imitate their moves. A person does not copy the dance moves exactly, but takes what they can and adds their own personality to it.[16]
Geographical zone On the basis of latitudinal extent, the globe is divided into three broad heat zones.
Parten's stages of play Modern scholars agree that Parten's theory has contributed substantially to our understanding of play, and while alternative classification schemes have been proposed, Parten's stages of play are still widely used.[1] However, there is disagreement on whether there is indeed a sequence of play stages that children go through â€“ for example, whether toddlers are really unable to play cooperatively, and whether solitary play in older children is less common or a sign of immaturity.[1] Alternative explanations suggest that types of play may be influenced by other circumstances (such as how well the children know one another).[1]