[IB Biology at GHS: Ecology & Conservation]

Course Objectives for IB Biology

Gresham HS

Ecology and Conservation

Topic Four: Ecology

Topic G: Ecology and conservation

Chapters 23-27

4.1 Communities and photosynthesis (5 hours)

4.1.1 Define ecology. (pg. 464)

4.1.1 Define ecosystem. (pg. 464)

4.1.1 Define population. (pg. 464)

4.1.1 Define community. (pg. 464)

4.1.1 Define species. (pg. 425)

4.1.1 Define habitat. (pg. 481)

4.1.2 Explain how the biosphere consists of interdependent & interrelated ecosystems. (pg. 517)

4.1.3 Define autotroph (producer) (pg. 510), heterotroph (consumer)(pg. 510), detritivore(pg. 510) and saprotroph (pg. 510, 633) (decomposer).

4.1.4 Describe what is meant by a food chain giving 3 examples, each with at least 3 linkages (four organisms). Food chains are best determined using real examples and real information based on local examples. A--->B indicates that A is being 'eaten' by B. The different classifications of food chains (grazer, decomposer, etc.) will not be required. (pp. 179, 510-514)

4.1.5 Describe what is meant by a food web. (pg. 510)

4.1.6 Define trophic level. (pg. 510)

4.1.7 Deduce the trophic level (s) of organisms in a food chain and a food web. The student should be able to place an organism at the level of producer, primary consumer, secondary consumer, etc.. as the terms herbivore and carnivore are not always applicable. (pp. 510-514)

4.1.8 Draw a food web given appropriate information, containing up to 10 organisms. A--->B indicates that A is being 'eaten' by B. The different classifications of food chains (grazer, decomposer, etc.) will not be required. (pg. 510)

4.1.13 Define autotroph (producer). (pg. 510)

4.1.14 Define heterotroph (consumer). (pg. 510)

4.1.15 Define detritivore. (pg. 510) 4.1.16 Define saprotroph (decomposer). (pp. 510, 633)

4.1.17 State that light is the initial energy source for almost all communities. (Reference to communities that start with chemical energy is not required.)

4.1.18 Explain the energy flow in a food chain.

4.1.19 State that when energy transformations take place, including those in living organisms, the process is never 100% efficient, commonlybeing about 10-20%.

4.1.20 Explain what is meant by a pyramid of energy and the reasons for its shape. (pg. 514)

4.2.21 Design a pyramid of energy given appropriate information. (Pyramids of numbers and biomass are the most problematical and so are not required. The lowest bar of the pyramid of energy represents gross primary productivity, the next bar the energy ingested as food by primary consumers, et al. The units being measured are energy per unit area per unit time. Reasons for the shape could include the various ways in which energy is lost between trophic levels.) (pg. 514)

4.2.22 Explain that energy enters and leaves an ecosystem, but nutrients must be recycled. (pg. 147) ?

4.2.23 Draw the carbon cycle to show the processes including photosynthesis, respiration, combustion and fossilization. (The details of the carbon cycle should involve the interaction of living organisms and the biosphere through the processes of photosynthesis, respiration, fossilization and combustion. Specific quantitative data is not required.) (pg. 506)

4.2.24 Explain the role of saprotrophs (decomposers) in returning elements to the environment in inorganic form. (Specific names of decomposer organisms are not required.) (pg. 510, 633)

4.2 Populations (3 hours)

4.2.1 Outline how population size can be affected by natality, immigration, mortality and emigration. (A formula relating these is not required; simply that the first 2 increase population size whilst the latter 2 decrease it.) (pp. 464-469)

4.2.2 Draw a graph showing the sigmoid (S-shaped) population growth curve. (pg. 471)

4.2.3 Explain reasons for the exponential growth phase, the plateau phase and the transitional phase between these 2 phases. (The emphasis should be placed upon the factors affecting population growth rate. The terms exponential growth phase, transitional phase and plateau phase will be used. The names lag, log, stationary, decline and death, sometimes used to describe the different phases of growth will not be required.) (pp. 470-476)

4.2.4 Define carrying capacity. (pg. 471)

4.2.5 List 3 factors which set limits to population increase. (pp. 466-469)

4.2.6 Define random sample.

4.2.7 Describe one technique used to estimate the population size of one animal species based on a capture-mark-release-recapture method. (Various mark and recapture methods exist. The simplest form, the Lincoln index, which involves one mark, release and recapture cycle is required. Population size = n1 X n2 / n3 n1 = number initially caught, marked and released n2 = number of individuals captured in the second sample n3 = number of marked individuals in the 2nd sample. It is important that students appreciate the importance of choosing an appropriate method for marking organisms - sometimes their life expectancy can be drastically reduced by the over application of some labeling substance.)

4.2.8 Describe 1 method of random sampling used to compare the population numbers of two plant species based on quadrat methods.

4.2.9 Calculate the mean of a set of values.

4.2.10 State the term standard deviation is used to summarize the spread of variables around the mean and that 68% of the values fall within one standard deviation of the mean (plus and minus).

4.2.11 Explain how the standard deviation is useful for comparing the means and the spread of ecological data between two or more populations.

4.3 Evolution (2 hrs)

4.3.1 Define evolution.

4.3.2 State that populations tend to produce more offspring than the environment can support.

4.3.3 Explain that the consequences of the potential overproduction of offspring is a struggle for survival.

4.3.4 State that the members of a species show variation (cross reference 3.3.3).

4.3.5 Explain how sexual reproduction promotes variation in a species. (Meiosis & fertilization)

4.3.6 Explain how natural selection leads to the increased reproduction of individuals with favorable heritable variations.

4.3.7 Discuss the theory that species evolve by natural selection.

4.3.8 Explain two examples of evolution in response to environmental change; one must be multiple antibiotic resistance in bacteria.

4.4 Classification (2 hours)

4.4.1 Define species.

4.4.2 Describe the value of classifying all organisms.

4.4.3 Outline the binomial system of nomenclature (use of both a genus and species name).

4.4.4 Stat that organisms are classified into the kingdoms prokaryotae, Protoctista, Fungi, Plantae & Animalia.

4.4.5 Apply and/ or design a key for a group of up to eight organisms.

4.5 Human impact (2 hours)

4.5.1 Outline 2 examples of local or global issues of human impact causing damage to an ecosystem or the biosphere, one of which must be the increased greenhouse effect. (In studying the greenhouse effect students should be made aware that it is a perfectly natural phenomenon and that without it organisms may have evolved differently. The problem lies in its enhancement by certain human activities. Knowledge that gases other than carbon dioxide exert a greenhouse effect is required.)

4.5.2 Explain the causes and effects of the 2 issues in 4.4.1, supported with data.

4.5.3 Discuss measures which could be taken to contain or reduce the impact of these issues, with reference to the functioning of the ecosystem.

G.1 Ecology of species (3 hours)

G.1.1 Outline the factors that affect the distribution of plant species including temperature, water, light, soil pH, salinity and mineral nutrients.

G.1.2 Explain the factors that affect the distribution of animal species including temperature, water, breeding sites, food supply and territory.

G.1.3 Deduce the significance of the difference between 2 sets of data using the students' t-test given the appropriate formula and tables. The t-test can be used to compare 2 sets of data and measure the amount of overlap. Large values of t indicates little overlap and almost certainly a difference between 2 sets of data. In contrast, a small value of t indicates a lot of overlap and probably no difference. A probability of 0.05 is regarded as significant and a critical value read off from a table. (See IB syllabus for the equation.) The t-test should only be used on normally distributed data, ideally with large samples (>30 measurements per set of data) and the value of t should be compared with the critical value at (infinite?) degrees of freedom. For sample sizes <30 the value of t is only approximate and the degrees of freedom is n1 + n2-2. If t is greater than or equal to then it is possible to reject the null hypothesis.

G.1.4 Explain what is meant by the niche concept, in terms of an organism's spatial habitat, its feeding activities and interactions with other organisms. (It has been said that whereas 'habitat' is an organism's address, 'niche' represents its profession.

G.1.5 Explain the significance of the principle of competitive exclusion.

G.2 Ecology of communities (3 hours)

G.2.1 Explain the following interactions between species, giving 2 examples of each: competition, herbivory, predation, parasitism and mutualism. (pp. 481, 490, 484-87)

G.2.2 Define gross production. (pg. 512)

G.2.3 Define net production. (pg. 512)

G.2.2 Define biomass.

G.2.4 Calculate the above values from given data. (Gross production - respiration = net production) (pg. 512)

G.2.5 Explain the small biomass and low numbers of organisms in higher trophic levels. (pg. 514)

G.2.7 Describe ecological succession using one example.

G.2.8 Explain the effects of living organisms on the abiotic environment with references to the changes occurring during ecological succession to climax communities.

G.2.9 Discuss the difficulties of classifying organisms into trophic levels.

G.3 Biodiversity and conservation (7 hours)

G.3.1 Discuss reasons for the conservation of biodiversity using rainforests as an example. Reasons should include ethical, ecological, economic, and aesthetic arguments.

G.3.2 Outline the factors that caused the extinction of two named animals and one plant species. (Choose examples other than dinosaurs. More recent examples would be appropriate, such as the dodo, etc.)

G3.3 Calculate the index of diversity using the Simpson formula and outline its significance. (See IB syllabus for the equation.)

G.3.4 Explain the use of biotic indices and indicator species in monitoring environmental change.

G.3.5 Outline the damage caused to marine ecosystems by the overexploitation of fish.

G.3.6 Discuss international measures that would promote the conservation of fish.

G.3.7 Discuss the advantages of in situ conservation of endangered species (terrestrial and aquatic nature reserves).

G.3.8 Outline the management of nature reserves.

G.3.9 Explain the use of ex situ conservation measures including captive breeding of animals, botanic gardens and seed banks.

G.3.10 Discuss the role of international agencies and measures in conservation including IUCN, the Rio Convention on Biodiversity, CITES, WWF and Red data books.

G.4 The Nitrogen Cycle (4 hours)

G.4.1 State that all chemical elements that occur in organisms are part of the biogeochemical cycles and that these cycles involve water, land and the atmosphere.

G.4.2 Explain that all such cycles summarize the movement of elements through the biological components of ecosystems (food chains) to form complex organic molecules and subsequently into simpler inorganic forms which can be used again.

G.4.3 Explain that chemoautotrophs can oxidize inorganic substances as a direct energy source to synthesize ATP.

G.4.4 State that chemoautotrophy is found only among bacteria.

G.4.5 Draw a diagram of a nitrogen cycle including the process of nitrogen fixation (free-living, symbiotic and industrial, denitrification, nitrification, feeding, excretion, root absorption, and putrefaction (ammonification). (pg. 507) ?

G.4.6 Outline the roles of Rhizobium, Azotobacter, Nitrosomonas, Nitrobacter, and Pseudomonas denitrificans.

G.4.7 Describe the conditions that favor denitrification and nitrification. (pg. 507) ?

G.4.8 Discuss the actions taken by farmers/gardeners to increase the nitrogen fertility of the soil including fertilizers, plowing/digging and crop rotation (use of legumes).

G.5 The impacts of humans on ecosystems (3 hours)

G.5.1 Describe the role of atmospheric ozone in absorbing ultra violet (UV) radiation. (pg 552) ?

G.5.2 Outline the effects of UV radiation on living tissues and biological productivity. (pg 552) ?

G.5.3 Outline the chemical effect that chlorine has on the ozone layer. (pg 552)

G.5.4 Discuss methods of reducing the manufacture and release of ozone-depleting substances including recycling refrigerants, reduction of gas-blown plastics and CFC propellants. (pg 552) ?

G.5.5 Outline the consequences of releasing raw sewage and nitrate fertilizer into rivers, including eutrophication, algal blooms, deoxygenation, increase in biochemical oxygen demand (BOD), and subsequent recovery. (Names of specific organisms not required.) .

G.5.6 Outline the origin, formation, and the biological consequences of acid precipitation (acid rain) on plants and animals. (pg. 551) ?

G.5.7 State that biomass can be used as a source of fuels such as methane and ethanol.

G.5.8 Explain the principles involved in the generation of methane from biomass, including the conditions needed, organisms involved and the basic chemical reactions.