1. Plate tectonics operating over geologic time has changed the patterns of land, sea, and mountains on the Earth's surface. As the basis for understanding this concept, students know

• the principle structures that form at the three different kinds of plate boundaries
  
• why and how earthquakes occur, and the scales used to measure their intensity and magnitude
  
• * explanation for the location and properties of volcanoes that are due to hot spots and those that are due to subduction.

2. Energy enters the Earth system primarily as solar radiation and eventually escapes as heat. As a basis for understanding this concept, students know

• the relative amount of incoming solar energy compared with Earth's internal energy and the energy used by society.
  
• the fate of incoming solar radiation in terms of reflection, absorption, and photosynthesis
  
• the different atmospheric gases that absorb the Earth's thermal radiation, and the mechanism and significance of the greenhouse effect.

3. Heating of Earth's surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents. As a basis for understanding this concept, students know

• how differential heating of the Earth results in circulation patterns in the atmosphere and oceans that globally distribute the heat
  
• the relationship between the rotation of the Earth and the circular motion of ocean currents and air in pressure centers
  
• the origin and effects of temperature inversions
  
• oceans, generation of horizontal and vertical ocean currents, and the geographic distribution of marine organisms, the distribution of rain forests and deserts on Earth in bands at specific latitudes.

4. Climate is the long term average of a region's weather and depends on many factors. As a basis for understanding this concept, students know

• weather (in the short run) and climate (in the long run) involve the transfer of energy in and out of the atmosphere
  
• effects on climate of latitude, elevation, topography, as well as proximity to large bodies of water and cold or warm ocean currents
  
• how the Earth's climate has changed over time, corresponding to changes in the Earth's geography, atmospheric composition and/or other factors (solar radiation, plate movement, etc.).

5. Each element on Earth moves among reservoirs in the solid earth, oceans, atmosphere and organisms as part of biogeochemical cycles. As a basis for understanding this concept, students know

• the carbon cycle of photosynthesis and respiration, and the nitrogen cycle
  
• the global carbon cycle in terms of the different physical and chemical forms of carbon in the atmosphere, oceans, biomass, fossil fuels, and the movement of carbon among these reservoirs
  
• movement of matter among reservoirs is driven by the Earth's internal and external sources of energy.

6. Life has changed Earth's atmosphere and changes in the atmosphere affect conditions for life. As a basis for understanding this concept, students know

• how the composition of the Earth's atmosphere has evolved over geologic time including outgassing, the origin of atmospheric oxygen, and variations in carbon dioxide concentration
  
• the location of the ozone layer in the upper atmosphere, its role in absorbing ultraviolet radiation and how it varies both naturally and in response to human activities.

7. The geology of California underlies the state's wealth of natural resources as well as its natural hazards. As a basis for understanding this concept, students know

• the resources of major economic importance in California and their relation to California's geology
  
• the importance of water to society, the origins of California's fresh water, and the relationship between supply and need.

8. Stability in an ecosystem is a balance between competing effects. As a basis for understanding this concept, students know

• biodiversity is the sum total of different kinds of organisms and is affected by alterations of habitats
  
• how to analyze changes in an ecosystem resulting from changes in climate, human activity, introduction of non-native species, or changes in population size.
  
• how fluctuations in population size in an ecosystem are determined by the relative rates of birth, immigration, emigration, and death
  
• how water, carbon, and nitrogen cycle between abiotic resources and organic matter in the ecosystem and how oxygen cycles via photosynthesis and respiration
  
• a vital part of an ecosystem is the stability of its producers and decomposers
  
• at each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat and this can be represented in a food pyramid

9. Mutation and sexual reproduction lead to genetic variation in a population. As a basis for understanding this concept, students know

• meiosis is an early step in sexual reproduction in which the pairs of chromosomes separate and segregate randomly during cell division to produce gametes containing one chromosome of each type
  
• only certain cells in a multicellular organism undergo meiosis
  
• how random chromosome segregation explains the probability that a particular allele will be in a gamete
  
• why approximately half of an individual's DNA sequence comes from each parent
  
• the role of chromosomes in determining an individual's sex
  
• how to predict possible combinations of alleles in a zygote from the genetic makeup of the parents.

10. A multicellular organism develops from a single zygote, and its phenotype depends on its genotype, which is established at fertilization. As a basis for understanding this concept, students know

• how to predict the probable outcome of phenotypes in a genetic cross from the genotypes of the parents and mode of inheritance (autosomal or X-linked, dominant of recessive)
  
• how to predict the probable mode of inheritance from a pedigree diagram showing phenotypes
  
• how genetic engineering (biotechnology) is used to produce novel biomedical and agricultural products.

11. The frequency of an allele in a gene pool of a population depends on many factors, and may be stable or unstable over time. As a basis for understanding this concept, students know

• why natural selection acts on the phenotype rather than the genotype of an organism
  
• why alleles that are lethal in a homozygous individual may be carried in a heterozygote, and thus maintained in a gene pool
  
• new mutations are constantly being generated in a gene pool
  
• variation within a species increases the likelihood that at least some members of a species will survive under changed environmental conditions
  
• * the conditions for Hardy-Weinberg equilibrium in a population, and why these conditions are not met in nature
  
• * how to solve the Hardy-Weinberg equation to determine the predicted frequency of genotypes in a population, given the frequency of phenotypes

12. Evolution is the result of genetic changes that occur in constantly changing environments. As a basis for understanding this concept, students know

• how natural selection determines the differential survival of groups of organisms
  
• a great diversity of species increases the chance that at least some organisms survive large changes in the environment
  
• the effects of genetic drift on the diversity of organisms in a population
  
• reproductive or geographic isolation affects speciation
  
• how to analyze fossil evidence with regard to biological diversity, episodic speciation and mass extinction
  
• * how to use comparative embryology, DNA or protein sequence comparisons, and other independent sources to create a branching diagram (cladogram) that shows probable evolutionary relationships
  
• * how several independent molecular clocks, calibrated against each other and using evidence from the fossil record, can help to estimate how long ago various groups of organisms diverged evolutionarily from each other