For natural selection to occur, several premises must be satisfied. Firstly, there must be variation in a population. If all individuals are the same, there is no variation on which selection can occur. Secondly, these traits must be heritable, meaning they are passed from parent to offspring. Natural selection cannot operate on traits that have no genetic basis. There must also be differential reproduction, which means that some individuals must reproduce more than others. When all of these factors occur, natural selection results in evolution as advantageous traits propagate throughout the population.
Natural selection is quite variable, as changes in the environment impact what traits are advantageous in a particular time and place. A good of example of this comes from Galapagos finches. These birds have varying beak sizes. Wide beaks are best for eating hard seeds, while long narrow beaks are more adept at exploiting the fleshy fruit from trees. Typically narrow beaks are more prevalent, but during drought conditions when trees cannot produce fruit, seeds become a more abundant food item. This results in those finches with wide beaks having more food available and reproducing more than those with narrow beaks. When droughts persist over many years, wide beaks replace narrow beaks as the most common, but this trend reverses when droughts end and fruits once again become available.
Organisms are consumers.
They eat (consume) other species and plants
Answer: consumers
Options for the question are not given. They are as follows:
a. arg or lys
b. ala
c. thr
d. leu or ser
e. Only termination codons
Answer:
d. leu or ser
Explanation:
Four codons code for proline amino acid. These are CCT, CCC, CCA, and CCG. Hydroxylamine causes C to change into T or G to change into A.
If first position is changed in each codon:
CCT = TCT (UCU)
CCC = TCC (UCC)
CCA = TCA (UCA)
CCG = TCG (UCG)
These codons produce Serine amino acid.
If second position is changed in each codon:
CCT = CTT (CUU)
CCC = CTC (CUC)
CCA = CTA (CUA)
CCG = CTG (CUG)
These codons produce Leucine amino acid.
Hence, out of the given options, option d. leu or ser is correct.
Answer:
<em>I believe the answer is D.</em>
Explanation:
Answer:
The neurons are unable to repolarize.
Explanation:
The cell membrane potential remain negative at the resting membrane potential. The potassium channels maintains the negative voltage inside the cell and makes the cell stable at resting membrane potential.
The scorpion agitoxin affects the potassium channels, the depolarize cell remains in the depolarize state because potassium channels are inhibited. The cells are unable to repolarize as the potassium channels are unable to enter in the cells.
