Question

Define population.

Answer 1

Hint: Population is characterized by natality rate, mortality rate, population density, age composition, growth forms, biotic potential, environmental resistance, sex ratio, age ration, population cycles and fluctuations.

Complete answer:
- Population is defined as the total number of individuals of a species living in a specific geographical area. The individuals can interbreed under natural conditions to produce fertile offspring and they function as a unit of biotic community.
- In a geographical area, the population is further divided into sub-groups called demes. The chances of sexual interaction are more between the members of the same deme than between the members of different demes of that population.
- Population density can be described as the number of organisms of a species per unit area. It reflects the success of a species in a given area.
- In the human population, it is done by total counting after every ten years. But it may be done by random sampling or indirectly, e.g. pug marks or faecal pellets to determine tiger population.
- Population size of a species of an area depends upon the availability of food, predation pressure and weather conditions. It may be very low during stressful conditions but very high during favourable conditions, e.g. for Siberian cranes at Bharatpur wetlands, the population size is less than 10 in a year, while for locusts in African countries, the population size may be millions during swarming.

Note: Population ecology is the branch of ecology that shows the relationship between ecology and population genetics and evolution. For the ecological studies, a group of organisms produced by even asexual reproduction also represent a population.