What you’ll learn7 learning objectivesChoose one objective for a focused lesson, or study the complete topic.19.4.1Population as a group of organisms• Describe a population as a group of organisms of one species, living in the same area, at the same timeSyllabus objective19.4.2Community as all of the populations• Describe a community as all of the populations of different species in an ecosystemSyllabus objective19.4.3Ecosystem as a unit containing• Describe an ecosystem as a unit containing the community of organisms and their environment, interacting togetherSyllabus objective19.4.4Factors affecting the rate• Identify and state the factors affecting the rate of population growth for a population of an organism, limited to food supply, competition, predation and diseaseSyllabus objective19.4.5Lag, exponential (log), stationary• Identify the lag, exponential (log), stationary and death phases in the sigmoid curve of population growth for a population growing in an environment with limited resourcesSyllabus objective19.4.6Interpret graphs and diagrams• Interpret graphs and diagrams of population growthSyllabus objective19.4.7Factors that lead to each phase• Explain the factors that lead to each phase in the sigmoid curve of population growth, making reference, where appropriate, to the role of limiting factorsSyllabus objective