Barnacles are attached to rocks and cannot travel to avoid natural disasters or to mate with other barnacle populations.
A heatwave in a small coastal town led to the dark barnacles along the shoreline dying off. The lighter-grey barnacles were more likely to survive and now, the population is mostly comprised of light-grey barnacles.
Question 19
What occurred in this population?
A. natural selection
B. gene flow
C. bottleneck effect
D. viral drift

can someone please help me with this question? I though that this would be natural selection but the answer is C and im not sure why? I thought that light grey barnacles was a selective advantage?
Thanks!

    abbey1234321
    The answer is C because the bottleneck effect is usually attributed to a natural disaster occurring which leaves a small unrepresentative sample alive. Here, the natural disaster is the heatwave which has killed many of the barnacles. Of those surviving, a large proportion of the barnacles would possess alleles for a light grey colour (this is what I mean by an unrepresentative sample. The original pre-heatwave barnacles population would not have such a high proportion of individuals with alleles for light grey). I don't think you're too incorrect but you're making a big assumption in that light grey barnacles was a selective advantage. I don't think anywhere in the question stem it mentions that it is a selective advantage nor does it mention any selection pressures which you can then infer a selective advantage from. Overall, answer C is a better option which is slightly more difficult to fault. 🙂

        Taaaa76 they would have a selective advantage, since they more likely to survive. However, because a random event has occurred (i.e. heatwave) and has reduced the genetic diversity of the population, the bottleneck effect/C makes the most sense. Yes, natural selection is almost always going to be present, but in this case, it's not the main thing that has occurred. Often with exam style questions, there is a somewhat right answer (i.e. A) but also a more correct answer (i.e. C). Hope that helps!

            _sophiestudies_
            So if it was a predator that came and ate all of the darker barnacles and the grey ones survived it would be natural selection. But since it was a natural disaster (heatwave) that has changed the gene pool then the bottleneck effect is specifically what is happening?

                I need help with this question:
                Question 10
                The balanced chemical equation for aerobic respiration is best represented by
                A. C6H12O6+ 6O2 --> 6CO2 +6H2O + 30-32ATP
                B. 6CO2 + 6H2O --> C6H12O6 +6O2
                C. C6H12O6 + 6CO2 --> 6O2 + 6H2O
                D. C6H12O6 + 6O2 + 30-32ATP + 30-32 Pi --> 6CO2 + 6H2O + 30-32ATP

                  I need help with another question:
                  Question 17
                  What is the difference between C3, C4 and CAM plants?
                  A. Unlike C3 and C4 plants, CAM plants, such as cactus, absorb carbon dioxide (CO2) during the day.
                  B. C4 plants immediately integrate CO2 into a 3-carbon compound, whereas C3 and CAM plants initially integrate CO2 into a 4-carbon compound.
                  C. C3 plants absorb more CO2 during the day, whereas C4 and CAM plants absorb more CO2 at night.
                  D. CAM plants are suited to temperate climates, C3 plants are suited to dry environments and C4 plants are suited to marine environments.

                    I have got yet another question:
                    So I have been getting this question a few times in exams and the answers vary from company exam to company exam. What can I expect VCAA to want as an answer for this?
                    Name the organelles of the cell involves in the production, transport, modification, and eventual secretion of the (protein) from the cell.
                    Or
                    Identify the sequence of organelles that is responsible for the production and secretion if (protein name).

                      Taaaa76
                      In our current study design you are not required to know the balanced equations for aerobic respiration and photosynthesis. All we need to know is the amount of ATP from each step in cellular respiration and the overall output (30 or 32ATP.
                      In the previous study design you did have to know the balanced equation so you might come across questions like this but for this year you are not required to know the balanced equation 🙂

                          Taaaa76
                          I am not sure if this question is correct. I have completed the same question before on a practise exam but the first option was different:
                          Question 17
                          What is the difference between C3, C4 and CAM plants?
                          A. Unlike C3 and C4 plants, CAM plants, such as cactus, absorb carbon dioxide (CO2) at night.
                          B. C4 plants immediately integrate CO2 into a 3-carbon compound, whereas C3 and CAM plants
                          initially integrate CO2 into a 4-carbon compound.
                          C. C3 plants absorb more CO2 during the day, whereas C4 and CAM plants absorb more CO2 at night.
                          D. CAM plants are suited to temperate climates, C3 plants are suited to dry environments and C4 plants
                          are suited to marine environments

                          This would make option A correct as CAM plants have the adaptation to absorb CO2 during the night to separate the light dependent and light independent stage by time. I am not sure what happened with the question on your end, maybe double check your question or look at where it is originally from?

                              Taaaa76
                              According to the Edrolo textbook these are the organelles you need to know for the direct production, transport, modification and eventual secretion of a protein:

                              1. Ribosome - site of protein synthesis
                              2. Rough Endoplasmic Reticulum - involved in initial folding of protein and transport to Golgi Body
                              3. Transport Vesicle - transports protein to Golgi body.
                              4. Golgi Body - Modifies proteins and then packages them into vesicles.
                              5. Secretory Vesicle - Transports proteins around the cell and fuses with plasma membrane to secrete proteins into the extracellular environment.

                              There are other organelles indirectly required for this process like mitochondria that produces ATP for the process but since it is not directly involved you are not required to write this is your answer. Hope this helps! 🙂

                                  abbey1234321
                                  Yea i looked over at it and I am pretty sure it says during the day, which is weird. Mistake maybe?
                                  Which practise exam have you done it on?
                                  Mine was from NEAP

                                    I have yet ANOTHER question lol:
                                    Which one of the following would be a good source of biomass for the process of ethanol production?
                                    A. Animal manure
                                    B. Bacteria cultures
                                    C. Yeast cultures
                                    D. Wood pulp
                                    I put C because yeast fermentation results in ethanol, but the answer is D somehow can someone explain?

                                      Taaaa76
                                      I was doing the same practise exam yesterday (neap 2022) ahaha.

                                      So biomass is plant or animal material that can be sourced from various industries that have carbon rich compounds that glucose and other sugars can be extracted from. The biomass itself is the source of glucose and sugars as an input for fermentation. Then to produce bioethanol, Yeast is added to this biomass after it has been broken down to anaerobically ferment and produce ethanol as an output.
                                      Therefore C would be incorrect because it cannot provide sugars and glucose for anaerobic fermentation. Although, I can see why you went with this answer.
                                      D is the correct answer because wood pulp contains cellulose, which be broken down to produce glucose.
                                      if this is still confusing or u have another question feel free to ask

                                          Hi, i got this question in a practise exam:
                                          Explain why RNA must be converted to DNA in RT-PCR
                                          2 mark question.

                                          Is RT-PCR on the study design??

                                          • ohio replied to this.