Imagine you are standing in a field and you see a group of butterflies. You notice that the butterflies are not identical to eac
h other even though they are all from the same species and the same population. One day you notice an individual that looks noticeably different from the other butterflies in the population. It has much larger wings and can fly faster than the other butterflies. This difference allows the butterfly to escape predation more efficiently than other butterflies in the population. The difference came about because this butterfly spent more time developing in warm moist areas of the habitat than other butterflies. Do you expect the following generations to be composed of butterflies with larger wings? a) Yes, this trait is advantageous so more butterflies will choose to develop in warm moist areas of the habitat. b) Yes, this represents a genetic mutation that will be passed onto offspring. c) No, this represents non-heritable variation caused by the environment. d) No, this represents heritable variation but this trait does not increase ability to mate so will not be passed to the next generation.
The correct answer is: b) Yes, this represents a genetic mutation that will be passed onto offspring.
A random mutation in a gene occurred and led to differences in the ability to escape predation. This feature of the butterfly is now advantageous, because allows them better survival. Since it is a heritable variation it will be passed to the offspring.
The secretion of the enzyme renin by the kidney is one mechanism used by the kidneys for blood pressure regulation. The secretion of renin is the first step leading to angiotensin II production, in what is known as the renin–angiotensin system (RAS). Renin catalyzes the conversion of angiotensinogen to angiotensin I, which is subsequently converted to angiotensin II by the angiotensin-converting enzyme (ACE).
