2016 Ch. 5 group PPt
- 1. Chapter 5 - Populations By: Alan Kim, Thomas Huh, Gianna Mor, and Audrey Raulli
- 2. 3-1: How Populations Grow Characteristics of Populations: Population Growth: Population density is the number of individuals per unit area ● Geographic distribution, density, and growth rate are three important characteristics of a population. ● Population density can vary tremendously depending on the species and its ecosystem ● The number of births, the number of deaths, and the number of individuals that enter or leave the population can affect population size. ● A population grows if its birthrate is greater than its death rate. If the death rate is greater than the birth rate, the population shrinks. Immigration is the movement of individuals into an area occupied by an existing population Emigration is the movement of individuals out of an area Audrey Raulli
- 3. 3-1: How Populations Grow Exponential Growth: Logistic Growth: ● Exponential growth occurs when the individuals in a population reproduce at a constant rate. ● A population will grow exponentially under ideal conditions and unlimited resources. ● In an exponential growing population, the number of individuals increases slowly. However, over time the population become larger. ● Logistic growth is a growth pattern in which a population’s growth rate slows or stops following a period of exponential growth. ● The growth of a population slows or stops as resources become less available. Carrying capacity: the largest number of individuals of a population that a given environment can support Audrey Raulli
- 4. 5-2: Limits to grow Limiting factors A limiting factor is a factor that causes population growth to decrease. There are two kinds of limiting factors density-dependent factors and density independent factors. Thomas Huh and Alan Kim
- 5. 5-2: Limits to grow Density dependent factors These density dependent factors, are factors that depend on the size of the population, include competition,predation, parasitism and, disease. Competition- This is when populations become more crowded, organisms compete with one another for food, water space, sunlight, and other important necessities. Predation:populations in nature are often controlled by predation, this is one of the best ways to control the population Parasitism and Disease:Parasitism and Disease both depend on the size of the population in order to spread around. These organisms are similar toThomas Huh and Alan Kim
- 6. 5-2: Limits to grow Density independent factors These factors affect all populations in a similar way, regardless of the size of the population. Unusual weather, natural disasters, seasonal cycles, and certain human activities-such as damming rivers and clear cutting forests- are all examples of density independent limiting factors Thomas Huh and Alan Kim
- 7. 5-3 Human Population Growth Historical Overview: Like the populations of many other living organisms, the size of the human population tends to increase with time. The size of the human population has increased over time. After a long, start, the worldwide population expanded following improvements in medicine, sanitation, agriculture, energy use, and technology. Patterns of Population Growth: Birth rates, death rates, and the age structure of a population help predict why some countries have high growth rates while other countries grow more slowly.Gianna Mor
- 8. 5-3 Words to know Demography- Scientific study of human populations. Demographic Transition- Change in a population from high birth and death rates to low birth and death rates. Age-Structure Diagrams- Graph of the numbers of males and females within different age groups of a population. Gianna Mor