Syllabus concepts to know

• C4.1.1 Populations as interacting groups of organisms of the same species living in an area
• C4.1.2 Estimation of population size by random sampling
• C4.1.3 Random quadrat sampling to estimate population size for sessile organisms
• C4.1.4 Capture–mark–release–recapture and the Lincoln index to estimate population size for motile organisms
• C4.1.5 Carrying capacity and competition for limited resources
• C4.1.6 Negative feedback control of population size by density-dependent factors
• C4.1.7 Population growth curves
• C4.1.8 Modelling of the sigmoid population growth curve
• C4.1.9 Competition versus cooperation in intraspecific relationships
• C4.1.10 A community as all of the interacting organisms in an ecosystem
• C4.1.11 Herbivory, predation, interspecific competition, mutualism, parasitism and pathogenicity as categories of interspecific relationship within communities
• C4.1.12 Mutualism as an interspecific relationship that benefits both species
• C4.1.13 Resource competition between endemic and invasive species
• C4.1.14 Tests for interspecific competition
• C4.1.15 Use of the chi-squared test for association between two species
• C4.1.16 Predator–prey relationships as an example of density-dependent control of animal populations
• C4.1.17 Top-down and bottom-up control of populations in communities
• C4.1.18 Allelopathy and secretion of antibiotics