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7th grade Science unit test unit 6, Answer key.
Natural Selection.
Question 1.
Consider the following scenario:
A drought hits the habitat of a semi-aquatic bird population. All ponds dry up, and fish populations decline. There are two groups of birds in the population that differ in leg length and diet. Long-legged birds eat fish, while short-legged birds eat insects. The drought has little effect on insect populations.
What is the main selective pressure in this scenario?
Answer, Fish population.
Question 2.
Which statement is accurate about variations?
Answer, Organisms with variations that give an advantage are more likely to survive.
Question 3.
Consider the following scenario:
In a muddy lake environment, some fish have brown scales. Most fish, however, have silver scales. Predators have a harder time seeing the fish with brown scales.
Which term best describes the brown scales?
Answer, Advantageous trait.
Question 4.
How did the Industrial Revolution impact the population of peppered moths in Britain?
Answer, The dark-colored moths become more common.
Question 5.
There are two varieties in a population of squirrels: short tails and long tails. Long-tailed squirrels are better at jumping and balancing in trees. Scientists observe that over the span of 100 years, the proportion of the population with long tails increases from 10% to 60%. Which statement is most likely?
Answer, The proportion of short-tailed squirrels may have DECREASED due to an INCREASE in trees.
Question 6.
Why is the cheetah gene pool small today?
Answer, Multiple bottleneck events.
Question 7.
After a bottleneck event, the population of rabbits in an area has significantly decreased. A decade later, the population of the rabbits recovers to its original numbers. Which statement is correct about the rabbits?
Answer, They are less likely to survive environmental changes because of the bottleneck event.
Question 8.
Facts or data are types of:
Answer, Evidence.
Question 9.
What change is observed in a distribution curve for a trait affected by directional selection?
Answer, It shifts either to the right or to the left.
Question 10.
In a population of birds, brightly colored males and very dull males survive best. Which type of selection is this, and what is most likely true about the proportion of males of intermediate coloring?
Answer, DISRUPTIVE; males of intermediate coloring make up a small part of the population.
Question 11.
Which action (is) an example of genetic modification (creating GMOs)?
Answer, making crops that are resistant to pesticides and insects.
Question 12. (This is an essay question, please don't use my exact answer you will be flagged for plagiarism, put this in your own words please and thank you.)
Imagine you are a scientist observing rats in the wild. As the rats reproduce, rats born with white fur slowly begin to outnumber rats with black fur. In three to five sentences, provide two or more different explanations of why the rats with white fur might be outnumbering the rats with black fur.
My answer, Rats with white fur are more common than rats with black fur. When rats reproduce they often will multiply rats with white fur. Rats with black fur often die out quickly then rats with white fur. Another explanation would be that rats with white fur are more common in certain areas then rats with black fur.
Question 13.(This is an essay question, please don't use my exact answer you will be flagged for plagiarism, put this in your own words please and thank you.)
Pretend you are a scientist observing three different varieties of a single bird species that are part of the same population. In three to five sentences, describe what genetic variations exist in your population. Then, using reasoning skills and mock evidence from your observations, describe the impact these traits have on the birds’ relationships with their environment and predators.
My answer, Some genetic differences in other bird species are beak size, colors of their feathers and the size of the birds. Some birds that live in other areas have different diets. Meaning the size of the birds can vary. While some bird species are colored to fit in with their surroundings. Which helps them hide from predators and build their populations. Beak size helps with the type of food they eat. Some birds get bigger due to more accessibility to food and/or genetics.
Question 14. (This is an essay question, please don't use my exact answer you will be flagged for plagiarism, put this in your own words please and thank you.)
Compare and contrast the advantages and disadvantages of selective breeding versus genetic modification. Why might a person choose to use selective breeding over genetic modification? Why might a person choose to create a GMO over a selectively bred organism? Use three to five sentences to formulate your argument.
My answer, Firstly, I'd like to point out that everyone has different opinions and points of views on certain things. GMO products can have pros and cons. A few pros of GMO products is that they won't have any infections or diseases in the product unlike if they were natural. Genetically modified foods can be made anyway the population or the consumers want it. So they are in a way perfect if you want your food product a certain way. However, some of the cons of GMO foods products are that there are tons of added products in the food. Unlike natural food products that have everything made naturally instead of genetically. Breeding foods make the food more organic and more natural than others. Organic foods are healthier than GMO foods because they are completely natural and there are processes to make sure the food is safe while not changing it.
Thank you, this is merely for checking your answers, please try it out on your own before using these.
(My answers are 100% correct)