Section 14-3 and 14-4 “Population” Write everything that is underlined

14.3 Population Density / 14.4 Population Growth Section 14.3 KEY CONCEPT: Each population has a density, a dispersion, and a reproductive strategy.

14.3 Population Density / 14.4 Population Growth I.Populations 1.Population density is a measurement of the number of individuals living in a defined space. 2.Population dispersion refers to how a population is spread in an area. There are three types of dispersion illustrated on the next slides:There are three types of dispersion illustrated on the next slides:

14.3 Population Density / 14.4 Population Growth a. clumped

14.3 Population Density / 14.4 Population Growth b.uniform

c. random

14.3 Population Density / 14.4 Population Growth Survivorship curves:Survivorship curves: –Type I: low level of infant mortality and an older population –common to large mammals and humans –Type II: survivorship rate is equal at all stages of life –common to birds and reptiles –Type III: very high birth rate, very high infant mortality –common to invertebrates and plants

14.3 Population Density / 14.4 Population Growth Section 14.4 KEY CONCEPT: Populations grow in predictable patterns.

14.3 Population Density / 14.4 Population Growth I.Population Growth 1.The size of a population is always changing. 2.Four factors affect the size of a population: a.Births b.Deaths c.Immigration (Moving into an area) d.Emigration (Moving out of an area)

14.3 Population Density / 14.4 Population Growth 3.Exponential growth is a rapid population increase due to an abundance (lots of) of resources.

14.3 Population Density / 14.4 Population Growth 4.Logistic growth is due to a population facing limited resources.

14.3 Population Density / 14.4 Population Growth 5.Carrying capacity is the maximum number of individuals in a population that the environment can support. This is due to limited resources (food, shelter, space)This is due to limited resources (food, shelter, space)

14.3 Population Density / 14.4 Population Growth A population crash is a dramatic decline in the size of a population over a short period of time.A population crash is a dramatic decline in the size of a population over a short period of time.

14.3 Population Density / 14.4 Population Growth 6.A limiting factor is something that keeps the size of a population down. Limiting factors can depend on the density of individuals in the population or not.Limiting factors can depend on the density of individuals in the population or not.

14.3 Population Density / 14.4 Population Growth 7.Density-dependent limiting factors are affected by the number of individuals in a given area. –Predation –Competition –Parasitism and disease

14.3 Population Density / 14.4 Population Growth 8.Density-independent limiting factors limit a population’s growth regardless of the density. a.unusual weather b.natural disasters c.human activities