IAL Biology Unit 4
Topic 5 – Energy Flow, Ecosystems and the Environment
5.1 Photosynthesis Overview
Understand the overall reaction of photosynthesis as requiring energy from light to split apart the strong bonds in water molecules , storing the fuel (glucose) by combining it with carbon dioxide and releasing oxygen into the atmosphere
5.2 Photophosphorylation and ATP
Understand how photophosphorylation of ADP requires energy and that hydrolysis of ATP provides an immediate supply of energy for biological processes
5.3 Light-Dependent Reactions
Understand the light-dependent reactions of photosynthesis , including how light energy is trapped by exciting electrons in chlorophyll and the role of these electrons in generating ATP , reducing NADP in cyclic and non-cyclic photophosphorylation and producing oxygen through photolysis of water
5.4 Light-Independent Reactions
(i) Understand the light-independent reactions as reduction of carbon dioxide using the products of the light-dependent reactions ( carbon fixation in the Calvin cycle , the role of GP , GALP , RuBP and RUBISCO )
(ii) Know that the products are simple sugars that are used by plants, animals and other organisms in respiration and the synthesis of new biological molecules ( polysaccharides , amino acids , proteins , lipids and nucleic acids )
5.5 Structure of Chloroplasts
Understand the structure of chloroplasts in relation to their role in photosynthesis
5.6 Absorption and Action Spectrum
Understand what is meant by the terms absorption spectrum and action spectrum
5.7 Chromatography of Chloroplast Pigments
Understand that chloroplast pigments can be separated using chromatography and the pigments identified using Rf values
5.8 CORE PRACTICAL 10
Investigate the effects of light intensity , light wavelength , temperature and availability of carbon dioxide on the rate of photosynthesis using a suitable aquatic plant.
5.9 Primary Productivity
(i) Understand the relationship between gross primary productivity (GPP) , net primary productivity (NPP) and plant respiration (R)
(ii) Be able to calculate net primary productivity
5.10 Efficiency of Biomass and Energy Transfers
Know how to calculate the efficiency of biomass and energy transfers between trophic levels
5.11 Population, Community, Habitat and Ecosystem
Understand what is meant by the terms population , community , habitat and ecosystem
5.12 Biotic and Abiotic Factors
Understand that the numbers and distribution of organisms in a habitat are controlled by biotic and abiotic factors
5.13 Concept of Niche
Understand how the concept of niche accounts for the distribution and abundance of organisms in a habitat
5.14 CORE PRACTICAL 11
Carry out a study of the ecology of a habitat , such as using quadrats and transects to determine the distribution and abundance of organisms, and measuring abiotic factors appropriate to the habitat.
5.15 Stages of Succession
Understand the stages of succession from colonisation to the formation of a climax community
5.16 Evidence for Climate Change
Understand the different types of evidence for climate change and its causes, including records of carbon dioxide levels , temperature records , pollen in peat bogs and dendrochronology , recognising correlations and causal relationships
5.17 Causes of Anthropogenic Climate Change
Understand the causes of anthropogenic climate change , including the role of greenhouse gases in the greenhouse effect
5.18 Carbon Cycle and Reducing Carbon Dioxide
Understand how knowledge of the carbon cycle can be applied to methods to reduce atmospheric levels of carbon dioxide
5.19 Extrapolation and Climate Models
(i) Understand that data can be extrapolated to make predictions and that these are used in models of future climate change
(ii) Understand that models for climate change have limitations
5.20 Effects of Climate Change
Understand the effects of climate change (changing rainfall patterns and changes in seasonal cycles ) on plants and animals ( distribution of species , development and lifecycles )
5.21 Temperature and Enzyme Activity
Understand the effect of temperature on the rate of enzyme activity and its impact on plants, animals and microorganisms, to include Q10
5.22 CORE PRACTICAL 12
Investigate the effects of temperature on the development of organisms (such as seedling growth rate or brine shrimp hatch rates), taking into account the ethical use of organisms.
5.23 Evolution through Mutation and Natural Selection
Understand how evolution (a change in allele frequency ) can come about through gene mutation and natural selection
5.24 Isolation and Speciation
Understand how isolation reduces gene flow between populations, leading to allopatric or sympatric speciation
5.25 Controversial Issues in Climate Change
Understand the way in which scientific conclusions about controversial issues, such as what actions should be taken to reduce climate change , or the degree to which humans are affecting climate change , can sometimes depend on who is reaching the conclusions
5.26 Reforestation and Sustainable Resources
Understand how reforestation and the use of sustainable resources , including biofuels , are examples of the effective management of the conflict between human needs and conservation
