New York State Chemistry RegentsNew York State Earth Science Regents

 
Evolution: Change Over Time
Living Environment Regents June 2010 Question 10 PDF Print E-mail
Thursday, 26 May 2011 15:31
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Correct Answer: (1) results from isolation of the organism from the rest of the population

Evolution refers to the changes that have transformed life on Earth from its earliest beginnings to the diversity that characterizes it today. There are five possible causes of evolution: natural selection, genetic drift, mutation, gene flow, and nonrandom mating. When an organism is isolated from the rest of the population and is able to reproduce in the new location, natural selection can occur and cause evolution. The species could have evolved due to its adaptation to the new environment.

Incorrect Answers:

(2) is due to a genetic code that is present in the gametes of the organism

Evolution could not occur because the genetic code is still present in the gametes of the organism. Thus, there is no change in species' genome.

(3) decreases the number of gene in the body cells of the organism

Genetic changes such as mutation in the body cells are not carried on to the next generation because they do not give rise to gametes. Thus, a change in the numbers of genes in the body cells could not cause evolution of species.

(4) causes a change in the environment surrounding the organism

A species evolve due to external factors such as reproductive mate, change in environment or location, etc. A characteristic may only change when an external factor drives a change, not the characteristic driving change in the environment and then promoting evolution on itself.
 
Living Environment Regents June 2010 Question 14 PDF Print E-mail
Monday, 30 May 2011 10:32
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Correct answer: (1) Species B and C can be found in today's environments

The illustration shown is an example of a cladogram, a diagram used to demonstrate ancestral relationships of species. On the left portion of the cladogram, time is indicated and it shows here that the bottom part of the cladogram is the initial stage of evolution, leading to the upper part of the diagram, which is the present. Thus, species E lived first, followed by species D, A, B and C. Since species B and C fall on the same vertical line in reference to time, which is the present, then they are both living at the present time, making the 1st statement in choices correct.

Incorrect answers:

(2) Species A and D evolved from E

Species A did not evolve from species E but they shared a common characteristic represented by the node between the branches leading to A and E. The ancestral line further evolved adding another characteristic that species A and E did not possess, leading to the formation of species D.

(3) Species A and C can still interbreed

Species A and C cannot interbreed because these are two entirely different species. Interbreeding can only occur and be successful, that is to be able to form offspring, only if it happened in the same species. For example, salamanders and lizards evolved from a common ancestor but they are different species. Lizards are more advanced, having claws or nails. Thus, they may have many similar characteristics but still they cannot mate for the simple reason that they are not the same species.

(4) Species A, B, and E all evolved from a common ancestor and all are successful today

All of the species mentioned may have evolved from one ancestral species. Species A and B also share a common characteristic, represented by the node between the two of them. However, species B is more advanced and the only one still living at the present, compared to species A and E.

 
Living Environment Regents June 2010 Question 28 PDF Print E-mail
Thursday, 26 May 2011 15:53
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Correct answer: (3) new varieties of plant species appear more frequently in regions undergoing climatic change

Evolution occurs only when there are changes occurring in the organism and in its environment. Since change is constant, then species continuously evolve. Climate change has been more evident than ever, and this leads to evolution of plant species.

(1) the extinction rate of species has decreased in the last 50 years.

Extinction, or the complete loss of a species, is caused by a change that the species cannot tolerate leading to a high death rate that overcomes the birth rate.

(2) many bird species and some butterfly species make annual migrations.

If there is evolution, migration of these species would be changed. Since it occurs the same way every year, then evolution is not exemplified in this statement.

(4) through cloning, the genetic makeup of organisms can be predicted

Cloning is the process of copying the genetic material of an organism to produce another organism that has the same genetic information. Cloning is not part of evolution because evolution is a natural process while cloning is a scientific technique conducted by experts.
 
Living Environment Regents June 2010 Question 60 PDF Print E-mail
Thursday, 26 May 2011 17:21
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It is a basic phenomenon that populations of organisms would evolve to be better suited to its habitat after several generations. For instance, a population of bacterium eventually resists a certain antibiotic because over time, the population has developed better traits for survival. This genetic event is called adaptation. Thus, the more exposure to antibiotics, the faster it would take for the genes of the bacteria to develop traits for resistance.
 
Living Environment Regents June 2010 Question 65 PDF Print E-mail
Monday, 30 May 2011 10:59
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Species A and B are the most closely related species because they have more similar amino acids. The arrangement of the amino acids codes for proteins during translation. Proteins form into complex three-dimensional shapes to become key cell structures and regulators of cell functions. Thus, species with similar amino acid sequences in their DNA also have similar characteristics.

 
Living Environment Regents June 2010 Question 76 PDF Print E-mail
Thursday, 26 May 2011 17:41
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Correct answer: (2) natural selection

Natural selection is the differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment. This differentiation of beaks is caused by their interaction with the environment. Each of them may have been exposed to different types of food, thus developed different kinds of beaks over time.

Incorrect answers:

(1) gene manipulation

Gene manipulation or genetic modification is done in laboratories by scientists to improve the characteristics of species. However, the change indicated above occurred naturally in the environment, thus it is not considered as an effect of gene manipulation.

(2) unchanging environmental conditions

Changes in species over time or evolution are caused by drastic or important changes in the environment. If there is no change evident, then the species would not evolve to have different beaks because it is not necessary.

(4) patterns of behavior learned from parent

Behavior refers to actions done by organisms in response to their environment. The change in beaks is not a behavioral transformation, thus this option is incorrect.
 
Living Environment Regents June 2010 Question 77 PDF Print E-mail
Thursday, 26 May 2011 17:44
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Correct answer: (2) niche

Niche refers to the sum total of the organism's utilization of the biotic and abiotic resources of its environment. Since there is overlap hunting, the species changed their niche to cope with the environment and its conditions.

Incorrect answers:

(1) habitat

Habitat refers to the particular location where species live. It was not mentioned in the given passage that the birds changed the location where they live. What they changed is the time of hunting so that they can perform their function efficiently.

(3) ecosystem

Ecosystem is a community and its physical environment. Species do not have the ability to change the entire ecosystem.

(4) biodiversity

Biodiversity is measured by the amount of species living in an ecosystem. The birds will not be able to change the count of species in the area by changing their hunting time.
 


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