adaptation of human beings to live on land
Answers
The human body readily responds to changing environmental stresses in a variety of biological and cultural ways. We can acclimatize to a wide range of temperature and humidity. When traveling to high altitudes, our bodies adjust so that our cells still receive sufficient oxygen. We also are constantly responding in physiological ways to internal and external stresses such as bacterial and viral infections, air and water pollution, dietary imbalance, and overcrowding.
This ability to rapidly adapt to varying environmental conditions has made it possible for us to survive in most regions of the world. We live successfully in humid tropical forests, harsh deserts, arctic wastelands, and even densely populated cities with considerable amounts of pollution. Most other animal and plant species are restricted to one or relatively few environments by their more limited adaptability.
Humans normally respond to environmental stresses in four ways:
biological responses
1. genetic change
2. developmental adjustment responses without genetic change.
3. acclimatization
4. cultural practices and technology
The first three are biological responses. The last three occur during our lifetime without further genetic change.
Genetic Change
When an environmental stress is constant and lasts for many generations, successful adaptation may develop through biological evolution. Those individuals who inherit a trait that offers an advantage in responding to particular stresses are more likely to survive longer and pass on more of their genes to the next generation. This is evolution through natural selection. For instance, people whose ancestors have lived in areas that have had endemic click this icon to hear the preceding term pronounced malaria for thousands of years often inherit some degree of immunity to this serious disease. The high incidence of sickle-cell trait among the people of Central Africa is largely the result of indirect selection for this trait by malaria. Heterozygous carriers of the sickling gene usually do not have sickle-cell anemia and are sufficiently resistant to the malarial microorganism that they are at a selective advantage. Another example of a genetic solution to an environmental stress is our ability to produce sweat as an aid in cooling our bodies in hot environments. It is not surprising that we have this capability because our immediate prehuman ancestors were tropical animals.
Genetic change in response to environmental stresses usually takes many generations to become widespread in a population. Fortunately, we also have other ways of responding more quickly as individuals during our own lifetime. The word adjustments is used here to refer to these shorter term physiological changes that are not inheritable. The word adaptations is reserved for inheritable genetic changes developed in a population over a long period of time.
Developmental Adjustment
One of the more powerful types of adjustments to environmental stresses is a change in growth patterns and development. This occurs in childhood and typically results in anatomical click this icon to hear the preceding term pronounced and/or physiological click this icon to hear the preceding term pronounced changes that are mostly irreversible in adulthood. Such permanent changes are referred to as developmental adjustment or developmental acclimatization.
Answer:
adaptation of human beings to live on land
1. Expand the range of adaptive options
2. Greater capacity to imagine , plan and communicate novel idea
3. Enlarged store of information about the ecological and social surroundings
4. Food sharing at home basis: enhanced social memory and buffering of uncertainty
5. certain many biological changes also occur within organisms like human beings
6. Enhanced mobility and dispersal capability.