Question | Answer |
What Is Biodiversity? | The diversity of genes, characteristics and the ecosystem the species lives in. Includes diversity within and between species. |
Describe what a population is | A group of interbreeding individuals within the same species in the same area |
Describe what a community is | The various populations that share one habitat or ecosystem |
What is the definition of abiotic factors, give some examples | Non living or physical factors such as solar energy input, climate, disasters, o2 concentration, pollution and topography |
What is the definition of biotic factors, give some examples | Living factors such as competition, predation, grazing, disease and mutualism (pilot fish) |
Describe what athropogenic effect is | Effects from human activity such as pollution |
Give an example of an adaptation to a cold habitat and how this benefits the animal | Small ears and tail reduce the surface area that essential heat is lost through so the animal will lose less heat and stay warmer |
Give an example of succession | Lichen are often the first organism to colonise bare surfaces and can cope in harsh conditions. This begins a community that changes over time |
Describe primary succession | This begins with an organism colonising an area never inhabited by anything. Succession continues in this area until a stable community is established |
What is a pioneer species, | AN organism that can cope with extreme conditions such as high temperature so they are the first to arrive in an area for succession |
How do the pioneer species change the area to be suitable for other organisms | They may break rock surfaces and allow other soils to be produced just enough for other organisms to be able to inhabit this area |
How do organisms such as moss allow for taller larger plants to survive in the area | Moss will build up more organic matter in soil so water can be held in the soil. Smaller plants can now colonise the further improving the area for bigger plants to colonise |
What is a climax community | Usually dominated by trees, this is an unchanged community (unless habitat changes) after succession has taken place to produce a stable community |
Describe secondary succession | Once inhabited but cleared bare soil is where this occurs. Pioneer species and dormant seeds will quickly inhabit the area |
Give some adaptations of seeds that make them an effective pioneer species | Dispersed by wind, rapid growth, short life cycle and abundant seed production |
Describe deflated succession and give an example | Human activity prevents any further succession. For example, grazing fields prevents any larger plants from growing so that these area can be used by humans |
Describe primary productivity | The rate at which energy is incorporated into organic molecles |
What is the purpose of producers (autotrophs) | They make an organic product from inorganic products. For example when light falls on them, energy is transferred into chemical energy store (glucose) |
Give the balanced equation for photosynthesis | |
What are reactants and products in the light dependent reaction | Light energy and hydrogen from photolysis of water is used to produce reduced NADP and ATP with oxygen as a waste product |
What are the reactants and product in the light independent reaction | Reduced NADP and ATP are used to reduce carbon dioxide into carbohydrates |
How can reduction occur | By the addition of a lone electron of by adding a hydrogen ion and an electron |
Describe the structure and purpose of the thylakoid membrane in the chloroplast | a system of interconnected flat fluid filled sacs. Chlorophyll and the electron transport chain are embedded in the membrane |
Describe the structure and purpose of the thylakoid space in the chloroplast | The fluid within the thylakoid membrane sacs which contains enzymes for photolysis |
Describe the structure and purpose of the outer membrane in the chloroplast | Freely permeable to molecules like water and carbon dioxide |
Describe the structure and purpose of the inner membrane in the chloroplast | contains transport molecules which regulate the passage of substances in and out of the chloroplast. Inner and outer form an envelope |
Describe the structure and purpose of the granum in the chloroplast | A stack of thylakoids joined to one another |
Describe the structure and purpose of the starch grain in the chloroplast | Stores the product of photosynthesis |
Describe the structure and purpose of the stroma in the chloroplast | the fluid surrounding the thylakoid membranes. Contains the enzymes needed for light-independent reactions (photosynthesis) |
Describe the structure and purpose of the DNA loop in the chloroplast | Chloroplasts contain genes for some of their proteins |
Describe a photosystem | In thylakoid membranes, photosynthetic pigments are arranged in clusters each called a photosystem |
Describe the process of the electrons beginning to travel across the electron transport chain when light is absorbed by the chlorophyll | Two electrons are raised an energy level (excited) Electrons travels across the electron transport chain on electron carrier molecules that are embedded in the thylakoid membrane |
What reactions transport the electrons across the ETC, what is used as energy and what is this process called? | The electrons undergo a series of oxidation and reduction reactions and this causes a decrease in energy as ATP is used up. This is called photophosphorylation |
What is the purpose of a second chlorophyll molecule on the electron transport chain | The second molecule replaces the lost electrons which maintains the flow of electrons on the chain |
What is occurring in the thylakoid space as the electrons are travelling across the electron transport chain | Photolysis - Enzyme catalyses the splitting of water into hydrogen ions, oxygen and electrons The electrons from this replace the lost electrons on the second chlorophyll molecule that were put into the electron transport chain |
What is the end product of this reaction and how does it occur | Electrons that have traveled along the ETC combine with NADP and hydrogen ions to form reduced NADP |
What is ATP made up of and what is its purpose in reaction of organisms | The purpose of ATP is a transport for energy that will 'power' reactions in organisms such as respiration |
Where does the independent reaction take place and how is the light dependant reaction connected to this process | In the stroma reduced NADP and ATP is used in the cycle |
Continue describing the process of the Calvin cycle up to when a hexose sugar is formed | The 3C compounds are reduced to form a 3c sugar phosphate (GALP). The hydrogen used is from reduced NADP and ATP is used to energize this reaction as it is endothermic 2/12 GALPs create a hexose sugar which can be converted into other organic compounds (amino acids, lipids) |
Describe the process of the calvin cycle up to when two 3 carbon molecules are formed | CO2 combines with RuBP (5c) which is catalyzed with RuBISCO. 6C compound formed immediately breaks down due to being unstable into two 3C molecules (GP) |
What are the rest of the GALPs used for in the Calvin | 10/12 GALPs are involved in the recreation of RuBP. The GALPs are rearranged to form 6 5C compounds which are phosphorylated using ATP to form RuBP |
Give some ways in which the glucose produced can be used in the plant | Respiration Sucrose which is transported around the plant (via phloem) Can b polymerized to form starch and cellulose lipids, amino acids, nucleic acid |
Describe dendrochronology | Studying tree rings, if the climate is colder and wetter then the rings are wider and vice versa. this can be tracked back 3000 years |
How does pollen analysis help us determine the past climate | Pollen grains from peat bogs can tell which plants were growing at a certain time and so what the climate was like to accommodate those plants at that certain time |
Describe the analysis of ice cores | Air bubble trapped in ice that was formed at a certain time can be analysed to give information on temperature and CO2 levels at certain times |
Give seven elements involved in the carbon cycle | CO2 in air and water Carbon in fossil fuels Carbonate rocks Carbon compounds in decomposers Carbon compounds in animals dead organic matter Carbon compounds in plants |
What are the criteria required for the Harvey Weinberg equilibrium to apply | Random mating Large population No migration No mutation No selection pressure |
What modern evidence proves Darwin's theory of descent from a common ancestor | All DNA molecules are the same in all organisms |
Give some examples of reproductive isolation | Geographical Behavioral Habitat Seasonal mechanical |
describe allopatric speciation | Interbreeding becomes impossible as a population is physically separated so the there is a change in allele frequency due to natural selection in one population leading to allopatric speciation |
Describe sympatic speciation | Two parts of a population can become isolated but be int eh same place leading to this type of speciation |
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