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D.1 d.2 Practice Test ANSWER KEY Option D — Evolution D1. (a) as latitude increases so does wing size / direct relationship / positive correlation [1] Do not accept directly proportional as line does not pass through origin. (b) (i) 1. at higher latitudes/above 45º European species have larger wings than American species/largest wing sizes seen in European flies; 2. European flies show more variation than American flies (steeper curve); 3. at lower latitudes/below 45º North American flies have larger wings than European species; 4. South American flies have smaller wing size than European/ N. American flies; [2 max] (ii) 1. American species show less variation because they have had less time to diverge / evolve; 2. size of American flies closer to that of flies recently introduced/founder effect/European founder population from low latitudes; 3. American flies exposed to different selective pressures; [1 max] (c) 1. These isolated populations will diverge (genetically) / separation of gene pools; 2. These isolated populations may become a new species / allopatric speciation; 3. The wing size will follow same trend as in Europe as population spreads to higher latitudes; 4. The wing size will follow same trend as in Europe because larger size favoured by higher latitudes; 5. The wing size may stay small due to smaller gene pool; [2 max] D2. (a) 1. One process need for the spontaneous origin of life is the non-living synthesis of simple organic molecules/amino acids from inorganic molecules; 2. Another process needed for the spontaneous formation of life is the assembly of these simple organic molecules into polymers/polypeptides; 3. Another process needed for the spontaneous formation of life the origin of selfreplicating molecules that made inheritance possible; 4. Another process needed for the spontaneous formation of life is the packaging of these monomer and polymer organic molecules into membranes with an internal chemistry different from their surroundings; [2 max] (b) 1. RNA is self-replicating and can perform catalytic activities; 2. short sequences of RNA have been able to duplicate/copy other RNA molecules accurately; 3. RNA enzyme/ribozyme are able to synthesize other molecules; 4. 3-dimensional structure of ribosome catalytic sites (for peptide formation) are composed of RNA; 5. RNA is able to store information in sequence of (4) nucleotides (similar to DNA); [2 max] D.2.1 More questions D2. (a) 1. limb bone pattern of mammals shows the same basic arrangement; 2. The similarity in Limb bones of mammals suggests that the limbs are derived from common ancestor/homologous structures; 3. Theses common ancestral bone pattern of the front limbs are adapted to different environment conditions and thus form and function were subject to different selective pressures; 4. suitable example; (eg wing of bat adapted for flight and limbs of mole for digging) [2 max] (b) 1. both forms of speciation result in the formation of new species by the splitting of an existing one; 2. in both forms of speciation, interbreeding by separated groups is prevented; 3. sympatric exist in same geographical area while allopatric exist in geographical isolation; 4. sympatric is due to reproductive/behavioural isolation while allopatric might not; 5. suitable example of mechanism or organisms for each (eg: allopatric: separation of formerly linked waterways into isolated ponds in which separate fish species evolve and sympatric: temporal isolation / maggots feeding on apples do not mate with maggots feeding on hawthorn / different calls isolating species of bats) D.3 b. 1. homologous structures evolved from a common ancestor while analogous structures did not; 2. example of homologous and example of analogous; (examples of both are needed) (c) a. transient polymorphism Is when there are two alleles in a gene pool/ a species is polymorphic; b. In transient polymorphism one allele gradually replacing another; c. Transient polymorphism is due to strong selection pressure for one allele over the other; d. example; (e.g. melanic moths/industrial melanism ) 3 max (d) 1. Punctuated equilibrium are periods of stability/little evolution/stasis, followed by periods of sudden major change/lot of evolution/rapid speciation; 2. During these periods of stability organisms become well-adapted to environment; 3. During the stable periods natural selection acts to maintain characteristics; 4. This equilibrium is punctuated by rapid environmental change; 5. An environmental change, such as volcanic eruption / meteor impact / change in sea level; 6. After a large environmental change there can be directional selection which leads to rapid evolution; Directional selection occurs if a change in the environment creates a selective pressure that strongly selects for a particular phenotype, then this directional selection will lead to rapid evolution; 7. 4 max 2. [7] e) A gene pool is all the genes in an (interbreeding) population 1