Term 4

A3.2.1—Need for classification of organisms

A3.2.2—Difficulties classifying organisms into the traditional hierarchy of taxa

A3.2.3—Advantages of classification corresponding to evolutionary relationships

A3.2.4—Clades as groups of organisms with common ancestry and shared characteristics

A3.2.5—Gradual accumulation of sequence differences as the basis for estimates of when clades diverged from a common ancestor

A3.2.6—Base sequences of genes or amino acid sequences of proteins as the basis for constructing cladograms 

A3.2.7—Analysing cladograms

A3.2.8—Using cladistics to investigate whether the classification of groups corresponds to evolutionary relationships

A3.2.9—Classification of all organisms into three domains using evidence from rRNA base sequences

B4.1.1—Habitat as the place in which a community, species, population or organism lives

B4.1.2—Adaptations of organisms to the abiotic environment of their habitat

B4.1.3—Abiotic variables affecting species distribution

B4.1.4—Range of tolerance of a limiting factor

B4.1.5—Conditions required for coral reef formation

B4.1.6—Abiotic factors as the determinants of terrestrial biome distribution 

B4.1.7—Biomes as groups of ecosystems with similar communities due to similar abiotic conditions and convergent evolution 

B4.1.8—Adaptations to life in hot deserts and tropical rainforest

B4.2.1—Ecological niche as the role of a species in an ecosystem

B4.2.2—Differences between organisms that are obligate anaerobes, facultative anaerobes and obligate aerobes 

B4.2.3—Photosynthesis as the mode of nutrition in plants, algae and several groups of photosynthetic prokaryotes

B4.2.4—Holozoic nutrition in animals

B4.2.5—Mixotrophic nutrition in some protists

B4.2.6—Saprotrophic nutrition in some fungi and bacteria

B4.2.7—Diversity of nutrition in archaea

B4.2.8—Relationship between dentition and the diet of omnivorous and herbivorous representative members of the family Hominidae

B4.2.9—Adaptations of herbivores for feeding on plants and of plants for resisting herbivory 

B4.2.10—Adaptations of predators for finding, catching and killing prey and of prey animals for resisting predation

B4.2.11—Adaptations of plant form for harvesting light

B4.2.12—Fundamental and realised niches

B4.2.13—Competitive exclusion and the uniqueness of ecological niches

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

C4.2.1—Ecosystems as open systems in which both energy and matter can enter and exit

C4.2.2—Sunlight as the principal source of energy that sustains most ecosystems

C4.2.3—Flow of chemical energy through food chains

C4.2.4—Construction of food chains and food webs to represent feeding relationships in a community

C4.2.5—Supply of energy to decomposers as carbon compounds in organic matter coming from dead organisms

C4.2.6—Autotrophs as organisms that use external energy sources to synthesize carbon compounds from simple inorganic substances

C4.2.7—Use of light as the external energy source in photoautotrophs and oxidation reactions as the energy source in chemoautotrophs

C4.2.8—Heterotrophs as organisms that use carbon compounds obtained from other organisms to synthesize the carbon compounds that they require 

C4.2.9—Release of energy in both autotrophs and heterotrophs by oxidation of carbon compounds in cell respiration

C4.2.10—Classification of organisms into trophic levels

C4.2.11—Construction of energy pyramids

C4.2.12—Reductions in energy availability at each successive stage in food chains due to large energy losses between trophic levels 

C4.2.13—Heat loss to the environment in both autotrophs and heterotrophs due to conversion of chemical energy to heat in cell respiration

C4.2.14—Restrictions on the number of trophic levels in ecosystems due to energy losses

C4.2.15—Primary production as accumulation of carbon compounds in biomass by autotrophs

C4.2.16—Secondary production as accumulation of carbon compounds in biomass by heterotrophs

C4.2.17—Constructing carbon cycle diagrams

C4.2.18—Ecosystems as carbon sinks and carbon sources 

C4.2.19—Release of carbon dioxide into the atmosphere during combustion of biomass, peat, coal, oil and natural gas

C4.2.20—Analysis of the Keeling Curve in terms of photosynthesis, respiration and combustion

C4.2.21—Dependence of aerobic respiration on atmospheric oxygen produced by photosynthesis, and of photosynthesis on atmospheric carbon dioxide produced by respiration

C4.2.22—Recycling of all chemical elements required by living organisms in ecosystems

D4.2.1—Stability as a property of natural ecosystems

D4.2.2—Requirements for stability in ecosystems

D4.2.2—Requirements for stability in ecosystems

D4.2.2—Requirements for stability in ecosystems

D4.2.5—Role of keystone species in the stability of ecosystems

D4.2.6—Assessing sustainability of resource harvesting from natural ecosystems

D4.2.7—Factors affecting the sustainability of agriculture

D4.2.8—Eutrophication of aquatic and marine ecosystems due to leaching

D4.2.9—Biomagnification of pollutants in natural ecosystems 

D4.2.10—Effects of microplastic and macroplastic pollution of the oceans

D4.2.11—Restoration of natural processes in ecosystems by rewilding

D4.2.12—Ecological succession and its causes

D4.2.13—Changes occurring during primary succession

D4.2.14—Cyclical succession in ecosystems

D4.2.15—Climax communities and arrested succession