DYNAMICS POPULATION Mariana Chavarriaga V 8a

D YNAMIC P OPULATION Vocabulary:  Population: All the individuals of a species that live together in an area.  Demography: The statiscal study of populations, make predictions about how a population will change.  Size: Number of individuals in a area

D YNAMIC P OPULATION Three key features of population  Growth rate. Birth rate (natality) death rate (mortality)  How many individuals are born vs. How many die  Birth rathe (b)- Death rate (d)= rate of natural increase(r)

D YNAMIC P OPULATION 4 factors that affect density 1. Immigration: Movement of individuals into a population. 2. Emigration: Movement of individuals out of a population. 3. Density-Dependent factors: Biotic factors in the environment that have an increasing effect as population size increases. Ex: Disease, Competition, Parasites. 4. Density-Independet factors: Abiotic factors in the environment that affect populations regardiess of their density. Ex: Temperature, Storms, Drought.

D YNAMIC P OPULATION Some images are very specific

D YNAMIC P OPULATION Population dynamics is the branch of life sciences that studies short-term and long-term changes in the size and age composition of populations

D YNAMIC P OPULATION The biological and environmental processes influencing those changes. Population dynamics deals with the way populations are affected by birth and death rates, by immigration and emigration, and studies topics such as ageing

D YNAMIC P OPULATION One common mathematical model for population dynamics is the exponential growth model.With the exponential model, the rate of change of any given population is proportional to the already existing population.

D YNAMIC P OPULATION Limited space for territories may often put a cap on the size of bird populations. In his well-known study of Florida Scrub jays, we found that the density of breeding pairs remained quite constant. In a stretch of about 550 acres of prime habitat, there was very close to one pair per 25 acres for each of the nine years In contrast, at the start of the breeding season in those same years, the overall density of jays in the area was three to four times as great.

D YNAMIC P OPULATION An example with the animals and the territory

D YNAMIC P OPULATION A population is a group of individuals who live together in the same habitat and are likely to interbreed. Each population has a unique physical distribution in time and space.

D YNAMIC P OPULATION