gather, process, present and analyse information from secondary sources to account for changes in human population numbers in the last 10 000 years and to discuss the potential impact of named examples of modern technologies on future human populations
The information following draws on estimates of human population growth produced from data identified from at least three sources
Early humans lived for 1.5 million years in small groups. The numbers were kept low by predators and the availability of food. The table below records the growth of the human population.
Years before present | Estimated human population (million) | Culture |
---|---|---|
10 000
|
5
|
early agriculture
|
6 000
|
7
|
advanced agriculture
|
150
|
1260
|
industrial revolution
|
40
|
3040
|
technological revolution
|
The factors that affect population growth are related to birth and death rates. During the last hundred years there has been a dramatic reduction in the death rate leading to a population explosion. Reasons for this include increased food supplies through agriculture advances, improved diet, improved medical technology, the advent of sanitation and public health programs, education and technological advancements. Many humans would once have died at a young age but are now living longer and dying of degenerative diseases such as cancer and heart disease. Humans are no longer selected for their favourable genes by the environment. Instead humans change the environment to suit their own needs.
For the first part look at the table above and find information on the population at other times in the last 10 000 years, say 4 000 years ago, 2 000 years ago and 1 000 years ago. If you are using a search engine some words to search for could be ‘human health’, ‘hygiene’, ‘estimated population’, ‘vaccination’, agriculture, ‘education’,’ technology’.
The Internet sites below are a good starting point.
For the second part consider such new technologies as ‘cloning’, ‘genetic engineering’, diagnostic medical machinery such as Magnetic Resonance Imaging (MRI)
The Internet sites below are a good starting point.
Cloning How stuff works Project
Future Shock, High Technology and the Human Prospect Uncommon Knowledge, Hoover Institution, Stanford University, California, USA
Useful information
Two named technologies that have had an impact on future human populations are cloning and gene replacement technology (gene therapy).
A clone is an exact genetic copy of DNA, tissues or an organism. Plant cloning has been going on for a long time but it has been harder to clone animals. There are two methods of cloning animals, embryo splitting and nuclear transfer. In embryo splitting, the embryo is split before it reaches the 32-cell size. This occurs naturally when identical twins are formed. In nuclear transfer cloning the nucleus of one animal is transferred to the cell of another organism (for example, Dolly the sheep). Cloning tissues for organ transplants is another use of cloning. Cloning skin for burn victims already occurs but if it is possible to clone nerve cells and more complex organs from stem cells then this will affect the future evolution of humans. It has been discussed that it may be possible to clone extinct animals such as the Thylacine (Tasmanian tiger).
Genetic therapy is the insertion of a working gene into an individual where the gene is not operating. This is being researched for the treatment of cystic fibrosis and insulin dependant diabetes.