3.1 Name the process represented by the diagrams above - NSC Life Sciences - Question 3 - 2017 - Paper 2
Question 3
3.1 Name the process represented by the diagrams above.
3.1.2 Give TWO reasons for your answer in QUESTION 3.1.1.
3.1.3 Identify the phases labelled C and D.
3.2 A ... show full transcript
Worked Solution & Example Answer:3.1 Name the process represented by the diagrams above - NSC Life Sciences - Question 3 - 2017 - Paper 2
Step 1
Name the process represented by the diagrams above.
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Answer
The process represented by the diagrams is Meiosis.
Step 2
Give TWO reasons for your answer in QUESTION 3.1.1.
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Answer
During meiosis, haploid cells are produced, which contain half of the original number of chromosomes.
Homologous chromosomes separate and move to opposite poles during the anaphase stage.
Step 3
Identify the phases labelled C and D.
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Answer
Phase C is Anaphase I and Phase D is Telophase I.
Step 4
Describe the changes in the insect population between 1995 and 1998.
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Answer
Between 1995 and 1998, the proportion of resistant insects increased significantly, from 0.15% to 99.1%. Conversely, the percentage of non-resistant insects decreased dramatically from 99.85% to 0.9%.
Step 5
Describe how natural selection caused insecticide resistance in this population.
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Natural selection played a pivotal role in the development of insecticide resistance in this population. Initially, there was variation in the insect population, with some insects being resistant to the insecticide while others were not. When the insecticide was applied, those resistant individuals survived and reproduced, passing the resistance trait to their offspring. Over time, the proportion of resistant insects increased, as many of the non-resistant insects were killed off by the insecticide.
Step 6
What evolutionary process is illustrated in the diagram above?
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Answer
The evolutionary process illustrated in the diagram is Speciation, which occurred through geographic isolation.
Step 7
Use the diagram to explain how the Species B evolved from the original population.
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Species B evolved from the original population of salamanders as the population became separated into two sub-populations by the Central Valley. Over time, each sub-population was exposed to different environmental conditions, leading to varied selection pressures. Natural selection acted differently on each sub-population, causing divergence in characteristics both genetically and phenotypically. As gene flow ceased, even if interbreeding occurred, the two populations became increasingly distinct, resulting in the formation of Species B.
Step 8
Explain why this is not an example of punctuated equilibrium.
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Answer
This process is not an example of punctuated equilibrium because it involves gradual changes over a long period of time. Punctuated equilibrium, in contrast, suggests that species remain static for long periods and then undergo rapid changes in short bursts. The process depicted shows continuous evolution rather than abrupt shifts.
Step 9
Give the number only of the skull belonging to the pelvis.
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Answer
(a) 3
(b) 1
(c) 2
Step 10
Give the LETTER of the pelvis and the NUMBER of the skull of the organism which is biped most of its adult life.
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Answer
The LETTER of the pelvis is B and the NUMBER of the skull is 1.
Step 11
Tabulate TWO anatomical differences between skulls 1 and 3 with respect to labels X and Y.
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Answer
Feature
Skull 1
Skull 3
X-foramen magnum
Located in a backward position
Located in a more forward position
Y-brow ridge
Less pronounced
More pronounced
Step 12
List ONE feature of the teeth of skull 3.
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Answer
Skull 3 has the most developed canines.
Step 13
Explain how mitochondrial DNA is used to support the 'Out of Africa' hypothesis.
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Answer
Mitochondrial DNA is inherited maternally, allowing researchers to trace lineage back to common ancestors. Analysis of mitochondrial DNA has revealed that all modern humans share a common ancestor from Africa. This supports the 'Out of Africa' hypothesis by indicating that all modern humans descended from early human populations that migrated out of Africa, while their descendants spread across the globe.
