<span>In Drosophila + indicates wild-type allele for any gene, m is mahogany and e is ebony.
Female parents are m+/m+ and males are +e/+e.
F1 are m+/+e, all wild type. F1 females are crossed with me/me males - the test cross.
Offspring will be : non recombinant m+/me, mahogany wild type or +e/me wild type ebony. OR
recombinant me/me mahogany ebony or ++/++ wild type.
As the two genes are 25 map units apart, the percentage of recombinants will be 25% and therefore percentage parental types will be 75%.
75% 1000 is 750. There are two parental types, so you would expect 375 of each. Therefore, you would expect 375 m+/me and 375 +e/me.
25% of 1000 is 250 split between two recombinants =125 of each. Therefore you would expect 135 me/me and 125 ++/++</span>
Answer:
This question is not well structured. Based on understanding, the correct structure should be: How are the processes of photosynthesis and respiration opposites of one another?
They are opposite because photosynthesis uses the products of cellular respiration and vice versa.
Explanation:
Photosynthesis and cellular respiration are both metabolic processes that occurs within the cells of living organisms. Photosynthesis is the process where green plants synthesize food (sugar) in the presence of sunlight using carbon dioxide (CO2) and water (H2O). The general equation is as follows:
6CO2 + 6H2O → C6H12O6 + 6O2
On the other hand, respiration is the process whereby cells of living organisms synthesize usable energy (ATP) for use by breaking down glucose (C6H12O6) in the presence of oxygen. The equation is as follows:
C6H12O6 + 6O2 → 6CO2 + 6H2O
Based on the observation of the reactants and products of each process, it can be realized that the PRODUCTS of one process is the REACTANTS of the other. In other words, photosynthesis makes use of CO2 and water as REACTANTS, which are the PRODUCTS of respiration while cellular respiration uses glucose and oxygen as REACTANTS, which are PRODUCTS of photosynthesis.
Answer:
1. Stabilizing Selection
2. Directional Selection
3. Disruptive Selection
Explanation:
Stabilizing Selection
This type of natural selection occurs when there are selective pressures working against two extremes of a trait and therefore the intermediate or “middle” trait is selected for. If we look at a distribution of traits in the population, it is noticeable that a standard distribution is followed:
Example: For a plant, the plants that are very tall are exposed to more wind and are at risk of being blown over. The plants that are very short fail to get enough sunlight to prosper. Therefore, the plants that are a middle height between the two get both enough sunlight and protection from the wind.
Directional Selection
This type of natural selection occurs when selective pressures are working in favour of one extreme of a trait. Therefore when looking at a distribution of traits in a population, a graph tends to lean more to one side:
Example: Giraffes with the longest necks are able to reach more leaves to each. Selective pressures will work in the advantage of the longer neck giraffes and therefore the distribution of the trait within the population will shift towards the longer neck trait.
Disruptive Selection
This type of natural selection occurs when selective pressures are working in favour of the two extremes and against the intermediate trait. This type of selection is not as common. When looking at a trait distribution, there are two higher peaks on both ends with a minimum in the middle as such:
Example: An area that has black, white and grey bunnies contains both black and white rocks. Both the traits for white and black will be favored by natural selection since they both prove useful for camouflage. The intermediate trait of grey does not prove as useful and therefore selective pressures act against the trait.
