The global population is estimated to reach 11 billion people by 2100. While this is a growth from the current 7 billion- it is clear that this figure indicates that the rate of population growth will slow down. Projections estimate that as living standards rise, each family will choose to have less children. 

Urbanisation and population growth are connected. The increasing urbanisation of the world is likely to be one of the factors slowing global population growth. This is because the fertility rate is frequently lower in urban areas as compared to rural.

Some factors that could influence this include the relative cost of having children, the need for children (e.g. to operate the family subsistence farm) and the availability of birth control.

Human wellbeing is a broad term which can be subjective, and is measured in different ways, but generally refers to a measurement of the health, happiness and/or general prosperity of people. 

Rural and urban living environments can have a significant impact on human wellbeing. The process of urbanisation, which is the shift from rural to urban living, has an impact on human wellbeing.

In urban environments, for example, it is easier to access government services, such as education, healthcare and cultural events. It is also much cheaper for the government to provide these because of economies of scale (for instance, building a doctor's surgery in a town of 1000 people vs. a town of 100. Both need the same resources but one will have much greater use). 

However, urbanisation can also mean that negative effects of human activity are concentrated in one area. For example, air pollution in China's very populous cities. It also means that people have to pay much more for land and housing, and get less. People may also encounter problems that are less drastic in rural areas, such as a large homeless population, slums, or organized crime. 

Invasion is a term for when a species of plant or animal that is alien to an area is introduced to an area, and is able to live in that area, often at the expense of the native plants or animals.  Typical examples of animal invasive species in Australia include those that were introduced by European settlement, including foxes and feral cats, and cane toads.

Succession is best defined as the gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established.

Urban renewal is a process in which run-down urban areas experiencing urban decay, such as slums, are redeveloped to provide for a better quality of living and wellbeing. 

Urban decay is the term given to an urban area that has become decrepit and poorly maintained, often associated with falls in population, high levels of poverty and crime, poor living standards generally and higher levels of pollution.