Population structure is what the population is composed of, or it shows what is the make up of a population. It divides the different gender of a place or community specifically males and females of different age groups. The population pyramid shows how the males and females of different age group is divided, it is the graphical illustration of the division of the two. Below is an example of a population pyramid. The figure above shows how the two gender with different age groups are divided considerably. The widest bar at the left side means that the largest population in Kentucky are males with the age of 20-24 years old. While on the female side, the largest population among the age groups are 0-4 years old. The reason of the large number of males in Kentucky is because it is the location of a large military installation. So the bars on the side determine the gender and estimate the number of them while the middle part determine the age of the different groups. Population Density is the number of individuals per unit area. Population density is determined by dividing the population by the area. For example, if the Philippines has a population of 103 million people and an area of 300,000 km so the population density is 323.33 persons per square kilometer. There are two reasons that can affect population density, the input and the output. The inputs can be high birth rate or immigration. High immigration or birth rate can affect the density if it is not balanced with the output which is death or emigration. If there is high inputs and low output, it can cause overpopulation. Population, Energetic, Biomass and ProductionEnergy flow is the transfer of energy from trophic level to another trophic level. Solar energy is transferred from the sun to the plants or the producers and will be taken in by the primary consumer whereas the energy transfers, it only transfer 90% of energy will be lost due to respiration. So the first consumer only get 10% of energy while 1% for the secondary consumer and only 0.1% left for the tertiary consumer. A lot of energy is lost between trophic levels, as a result the last consumer receives the lowest energy. Population Strategies There are two general life strategists; these are the r and k strategists.Those living beings portrayed as r-strategists regularly live in unsteady, eccentric conditions. Here the capacity to recreate quickly (exponentially) is imperative. Such life forms have high fertility (glossary) and generally little interest in any one descendants singular, they are normally powerless and subject to predation and the changes of their condition. The “vital plan” is to surge the living space with descendants so that, paying little heed to predation or mortality, at any rate a portion of the offspring will make due to recreate. Living beings that are r-chosen have short life expectancies, are by and large little, snappy to develop and squander a considerable measure of vitality. Examples of these are salmon, corals, insects and bacteria. K-strategists, then again involve more steady situations. They are bigger in estimate and have longer futures. They are more grounded or are better secured and by and large are more vitality productive. They deliver, amid their life expectancies, less descendants, yet put a more prominent interest in each. Their regenerative procedure is to develop gradually, live near the conveying limit of their living space and deliver a couple of offspring each with a high likelihood of survival. Normal K-chose living beings are elephants, and people. The table beneath compresses a portion of the contrasts between r-life forms and K-life forms. Examples of these are monkeys, humans, and elephants.