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Evolution: Change Over Time
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Living Environment Regents August 2010 Question 14 |
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Friday, 27 May 2011 12:40 |

Correct answer: (2) The fossil record provides samples of every organism that ever lived.
Fossil records refer to all the fossil samples found on rocks and sediments, whether discovered or not. These records reflect the evolution of organisms-from those that are already extinct due to failure of survival, to those that have evolved and lived up to the present.
Incorrect answers:
(1) Genetic alterations occur every time cell reproduction occurs.
Evolution refers to the changes that occur in organisms over time. Evolution is usually brought about by alterations in the environment that cause a change in the genotype of an organism. Genetic alterations such as recombination of genetic information normally occur during meiosis and are not considered as evolution.
(3) Populations that have advantageous characteristics will increase in number.
Though this statement is true, but it does not support the concept of evolution. Evolution refers to the changes that occur in organisms over time due to the disadvantageous circumstances that occurred in its environment.
(4) Few organisms survive when the environment remains the same.
This statement is not true. Ecological stability is usually advantageous for organisms because they no longer need to adapt to any changes. Thus, when there is stability, most populations would increase in number.
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Living Environment Regents August 2010 Question 27 |
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Friday, 27 May 2011 13:31 |

Correct answer: (2) There are few native predators of rabbits.
When there are few predators of an organism, then that organism faces less risk in survival. Reproduction rate would be high, and mortality rate (usually caused by predation or shortage of food) would be low.
Incorrect answers:
(1) Rabbits have a high metabolic rate.
The higher the speed of metabolism, the more food would be needed in order for the population of rabbits to survive. Thus, metabolic rate is not a factor in the predominance of rabbits in the area.
(3) Additional rabbit species have been introduced.
If additional rabbit species were introduced, then there would be more species to compete with the resources available. This will eventually lead to death of some rabbits, instead of increase in number.
(4) There is an increase in rabbit competitors.
If there are many competitors for the rabbits, then there would be shortage of food, which may lead to death of a number of rabbits and its competitors.
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Living Environment Regents August 2010 Question 71
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Friday, 27 May 2011 18:19 |

The small and middle ground finches eat mainly plant food while the warber finches eat only animal food. Since the ground finches and the warber finches have an entirely different type of diet, then sharing an island as habitat would not be disadvantageous for both finches.
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Living Environment Regents August 2010 Question 72 |
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Friday, 27 May 2011 18:29 |
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Correct answer: (2) the selection of different shaped beaks that best suit different niches
Finches use their beaks for feeding. Thus, the shapes of their beaks depend on the type of food that they eat. Feeding habit is part one the ecological niche of organisms. Niche is the sum total of an organism's utilization of the biotic and abiotic resources of its environment.
Incorrect answers:
(1) asexual reproduction of these finch species
Asexual reproduction is the type of reproduction involving only one parent that produces genetically identical offspring by budding or division of a single cell or the entire organism into two or more parts. Finches do not undergo asexual reproduction. They produce offspring through sexual reproduction.
(3) the genetic recombination associated with mitotic cell division
This statement is incorrect because genetic recombination can only occur during meiosis, a two-stage type of cell division in sexually-producing organism that results in gametes with half the chromosome number of the original cell.
(4) the genetic engineering of the DNA of each of these species
Genetic engineering is not necessary to create finches with different types of beaks.
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