Question:
A population of organisms is represented by three black marbles and three gray marbles. The gray organisms have a beneficial genetic mutation. Draw a model that shows natural selection over three generations of these organisms
Answer:
lThe population will suffer Directional selection. In the attached files you will find the drawing of the model.
Explanation:
Natural selection is the result of the phenotype-environment interaction which determines gene destiny in space and time, selecting beneficial alleles and increasing their frequency in the population. Among other types of natural selection, we can find the directional selection.
Directional selection increases in the proportion of individuals with an extreme phenotypic trait, in this case, the color of the organisms. This selection presents more frequently in those cases in which interactions between living organisms and the environment modify in the same direction.
Directional selection leads to the fixation of the beneficial allele and the consequent loss of the other one. In this case, for example, the gray suffered a beneficial mutation, and after three generations the allele codifying for this mutation shows an increase in its frequency, approaching fixation.
Answer:
c) melatonin
Explanation:
Melatonin its a hormone formed by the pineal gland, which regulates an individual wake cycles and sleep. Jetlag alters the hormone function leading to an alteration with the body clock of the persom.
Jetlag is a sleep disorder common to those who travel swiftly over several time zones. It is not a permanent sleep disorder. Its due to the body's internal clock lacking sync with cues generated in a different time zone, Cues may be due to light exposure and how often the person eats.
A basic factor on ones internal clock is sunlight. It controls the regulation of melatonin which aid in synchronizing cells in the body.
Specific cells of the tissue at retina moves the light signals the thypothalamus.
At night, the hypothalamus signal to the pineal gland to produce melatonin. At daylight hours, the reverse is the case.
Answer:
True
Explanation:
In a criterion validity test, the results of the test are correlated with the outcomes in future. In this study, the measures of gambling is used to depict the possible outcomes. If the clients tested on gambling measure score high, then it gives the relation of their gambling frequency in past.
It is a predictive validity type of criterion validity test in which it is estimated that how likely the test or measure score can depict the future or past behaviour of the client.
Thus it is true
<span>In response to a body temperature above the set point, two effector responses in mammals could be sweating and panting.
</span><span>Negative feedback stimulate activities of effectors (including sweat glands) that lower the temperature.</span>
