Bullet point notes

GROWTH

¨      Growth of brain and head very rapid in early years

¨      Enables scope for greater learning in childhood;

¨      allows development of complex types of behaviour;

¨      extended childhood allows longer period of learning;

¨      No need for reproductive organs to develop until adulthood;

¨      Reproductive organs develop slowly until puberty (12/13 years), when development is faster;

¨      Growth of reproductive organs at puberty allows reproductively mature individuals to be distinguishable;

¨      Reproductive organs are developing when the body/ person is mature enough to rear children

¨      delays reproduction until physical/ mental maturity reached.

AGING

¨      Osteoporosis /loss of calcium from bones/ rate of cell replacement decreases/ less protein made as DNA becomes defective;

¨      fall in metabolic rate/decreased activity;

¨      loss of brain cells causes slower responses, slower learning ability, loss of memory;

¨      lower rate of nervous conduction reduces reaction time;

¨      cartilage on joints wears own/arthritis reduction in ease of movement;

¨      arteriosclerosis/atherosclerosis reduce efficiency of circulatory system

¨      reduced vital capacity of lungs/ reduced elasticity become more breathless on exertion;  

¨      Faulty copying of DNA and a lifetime of exposure to mutagens leads to accumulated genetic changes/mutations. So faulty proteins may be made

¨      cross-linking of proteins such as collagen in connective tissue, causes connective tissue to stiffen e.g. in heart, affecting resting cardiac output;

¨      other effect, e.g. wrinkling of skin/ reduced renal filtration rate/ slower circulation of blood.

¨      Body’s immune system produces antibodies against its own cells as the immune system deteriorates with age. Which also allows abnormal cells to proliferate

DEMOGRAPHICS

• During the high stationary stage the population has a high fluctuating death rate and birth rate. The diseases are mainly infectious diseases e.g. cholera. Many such diseases are waterborne. These usually affect children most causing a high infant mortality. There is an absence of medical facilities. There is an uncertain food supply.

• In the early expanding stage (Agricultural revolution meant) more food was available/better diet. There was also better sanitation/water supply.

• In the late expanding stage children ceased to be economically useful/child labour laws passed/education compulsory. This made the desired family size smaller (especially when infant mortality decreased).

• In the low variable stage there is improved contraception and women’s aspirations depend on lower family size