Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Limits to Growth Honors Biology Facilitator: Mr. Lee Room 320 Objectives • Identify factors that limit population growth • Differentiate between density-dependent and density-independent limiting factors Limiting Factors • Limiting factors cause population growth to decrease • Examples: – Weeds & crop plants competing for light, space, nutrients in a vegetable garden – Predator-prey relationship of a toad and a mouse Limiting Factors… – A limited resources base can affect the long-term survival of a species – Even the human population may be limited by: • Availability of food and living space • Disease • Natural disasters Density-Dependent Limiting Factors • A limiting factor that depends on population size is called a density-dependent limiting factor • The factor only becomes limiting when the population density reaches a certain level Density-Dependent Limiting Factors … • Density-dependent limiting factors include: – Competition – Predation – Parasitism – Disease Competition • When populations become crowded, organisms compete for food, water, space, sunlight, etc. • Competition can also occur between members of different species – This is a major force behind evolution – Both species are under pressure to change in ways that decrease their competition Predation • Predation: Predation is the predator-prey relationship Parasitism and Disease • Parasites can limit the growth of a population • Parasites take nourishment at the expense of their host • When the host becomes weakened, they are more likely to contract a disease Density-Independent Limiting Factors • These factors affect all populations in similar ways regardless of population size • Examples are: • Unusual weather • Natural disasters • Seasonal cycles • Human activities Review • Identify factors that limit population growth: – Limiting factors cause population growth to decrease Review… • Differentiate between density-dependent and density-independent limiting factors: – Density-dependent limiting factors depends on population size – Density-independent limiting factors affect all populations in similar ways regardless of population size Learn Long Live Long