Syllabus concepts to know

• 2.1.1 The biosphere is an ecological system composed of individuals, populations, communities, ecosystems.
• 2.1.2 An individual organism is a member of a species.
• 2.1.3 Classification of organisms allows for efficient identification and prediction of characteristics.
• 2.1.4 Taxonomists use a variety of tools to identify an organism.
• 2.1.5 A population is a group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding.
• 2.1.6 Factors that determine the distribution of a population can be abiotic or biotic.
• 2.1.7 Temperature, sunlight, pH, salinity, dissolved oxygen and soil texture are examples of many abiotic factors that affect species distributions in ecosystems.
• 2.1.8 A niche describes the particular set of abiotic and biotic conditions and resources upon which an organism or a population depends.
• 2.1.9 Populations interact in ecosystems by herbivory, predation, parasitism, mutualism, disease and competition, with ecological, behavioural and evolutionary consequences.
• 2.1.10 Carrying capacity is the maximum size of a population determined by competition for limited resources.
• 2.1.11 Population size is regulated by density-dependent factors and negative feedback mechanisms.
• 2.1.12 Population growth can either be exponential or limited by carrying capacity.
• 2.1.13 Limiting factors on the growth of human populations have increasingly been eliminated, resulting in consequences for sustainability of ecosystems.
• 2.1.14 Carrying capacity cannot be easily assessed for human populations.
• 2.1.15 Population abundance can be estimated using random sampling, systematic sampling or transect sampling.
• 2.1.16 Random quadrat sampling can be used to estimate population size for non-mobile organisms.
• 2.1.17 Capture–mark–release–recapture and the Lincoln index can be used to estimate population size for mobile organisms.
• 2.1.18 A community is a collection of interacting populations within the ecosystem.
• 2.1.19 Habitat is the location in which a community, species, population or organism lives.
• 2.1.20 Ecosystems are open systems in which both energy and matter can enter and exit.
• 2.1.21 Sustainability is a natural property of ecosystems.
• 2.1.22 Human activity can lead to tipping points in ecosystem stability.
• 2.1.23 Keystone species have a role in the sustainability of ecosystems.
• 2.1.24 The planetary boundaries model indicates that changes to biosphere integrity have passed a critical threshold.
• 2.1.25 To avoid critical tipping points, loss of biosphere integrity needs to be reversed.
• 2.1.26 There are advantages of using a method of classification that illustrates evolutionary relationships in a clade.
• 2.1.27 There are difficulties in classifying organisms into the traditional hierarchy of taxa.
• 2.1.28 The niche of a species can be defined as fundamental or realized.
• 2.1.29 Life cycles vary between species in reproductive behaviour and lifespan.
• 2.1.30 Knowledge of species’ classifications, niche requirements and life cycles help us to understand the extent of human impacts upon them.