Transcript Ecosystems
Unit 7: Ecology Left Side Pg # Right Side Pg # Unit Page 34 Table of Contents 35 Levels of Organization 36 C.N. – Ecology Part 1 37 Sources of Energy Tree Map 38 C.N. – Energy Flow 39 Food Chain Activity 40 Food Chain/Web Worksheet 41 Community Interactions Tree Map 42 C.N. – Community Interactions 43 Population Growth 44 C.N. – Populations 45 Populations Chapter 5-1 Population Ecology Population: group of individuals of the same species living in an area. The size of a population can effect its interactions within an ecosystem. There are several factors that determine the size of a population. Characteristics of Populations 3 Characteristics of a Population 1) Geographic Distribution: describes the area inhabited by a population 2) Population Density: the number of individuals in a given area 3) Growth Rate: rate at which a population increases or decreases Population Size Population size is affected by: Things that cause a population to GROW: 1) Births 2) Immigration (new individuals join a population) Things that cause a population to DECLINE (decrease): 1) Deaths 2) Emigration (individuals move out of the the population) Limiting Factors 2 Types of Factors limit population growth (result in deaths & population decline): 1) Density-dependent The larger the population, the faster resources are used. This results in limiting factors such as: Competition for food, water, space, & mates Disease and Predation 2) Density-Independent Limiting factors like natural disasters, climate changes, and temperature can affect any population, regardless of its size Lynx & Hare Populations Patterns of Growth 1) Exponential Growth 2) Logistic Growth 1) Exponential Growth Under ideal conditions, individuals in a population reproduce at a constant rate Many births & few deaths Must have: unlimited resources no predators or disease Produces J-shaped curve Exponential Growth Curve Model for Exponential Growth In natural conditions, exponential growth does not last long. Limiting factors control how large a population can grow. Logistic Growth Logistic Growth: as resources become limited, a population’s growth slows or stops The population reaches the limit the environment can support Produces a S-shaped curve Logistical Growth Curve Carrying Capacity: the maximum # of individuals the environment can support The population size has leveled off Birth rate = death rate # of immigrants = # of emigrants Human Population Currently, the human population is growing at an exponential rate. With more people on the planet, we require more resources to keep us alive and produce more waste with our activities. Most ecological problems are caused by human activities. Habitat destruction, pollution, global warming, ozone depletion, and endangered species