4. List the attributes that populations possess but not individuals
The term population refers to a group of individuals of any species living in a well-defined geographical area, sharing or competing for similar kind of resources and potentially interbreed.
Population Attributes: A population has certain attributes that an individual organism does not have. For example, individuals may have births and deaths, but a population has birth rates and death rates. The various population attributes are as follows:
1. Birth rate (natality)- It is the ratio of live births in an area to the population of an area. It is expressed as the number of individuals added to the population.
2. Death rate(mortality)- It refers to the live deaths in an area to the population of an area. It is expressed as the number of individuals removes from the population.
3. Sex ratio- It is the ratio of the number of male or female individuals per 1000 individuals.
4. Age distribution- A population at a given time is composed of different individuals belonging to different age groups. If the age distribution is plotted for the population, the resulting structure is called age pyramids. The shape of pyramids reflects the growth status of the population.
5. Population density- The number of individuals of a population present per unit area at a given time.