Following general conditions are necessary for natural selection to occur in population:
- More organisms are born than can survive.
- Organisms vary in their characteristics, even within a species.
- Differences in reproduction and survival are due to variation among organisms.
According to Charles Darwin's theory of evolution by natural selection, organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation.
Galapagos Finches: The Galapagos finches studied by Darwin on his famous voyage are probably the most common example of natural selection.
The options attached to the above question are given below:
A) The boys at first were very polite about my medals and asked me what I had done to get them.
B) I showed them the papers which were written in very beautiful language of full of fratellanza and abnegazione but which really said with the adjectives removed that I had been given the medals because I was an American.
C) after that their manner change a little toward me although I was their friend against Outsiders
D) I was afraid but I was never really one of them after they had read the citation because it had been different with them and they had done very different things to get their medals.
E) I had been wounded it was true but we all knew being wounded after all was really an accident.
ANSWER
The correct option is D.
In the statement given in option D, it can be seen that the speaker was formerly a soldier, who had fought in a war and had been awarded a medal to that effect. But despite knowing about this meritorious service that he had rendered to his country and the award he was given, he was not really accepted as an inner person by the group of people that was refereed to in the statement. They did not think much of him.
Mitosis
Involves one cell division?
Results in two daughter cells
Results in diploid? daughter cells? (chromosome? number remains the same as parent cell)
Daughter cells are genetically identical
Occurs in all organisms except viruses
Creates all body cells (somatic?) apart from the germ cells? (eggs and sperm)
Prophase is much shorter
No recombination/crossing over occurs in prophase.
In metaphase individual chromosomes (pairs of chromatids) line up along the equator.
During anaphase the sister chromatids are separated to opposite poles.
Meiosis
Involves two successive cell divisions
Results in four daughter cells
Results in haploid? daughter cells (chromosome number is halved from the parent cell)
Daughter cells are genetically different
Occurs only in animals, plants and fungi
Creates germ cells (eggs and sperm) only
Prophase I takes much longer
Involves recombination/crossing over of chromosomes in prophase I
In metaphase I pairs of chromosomes line up along the equator.
During anaphase I the sister chromatids move together to the same pole.
During anaphase II the sister chromatids are separated to opposite poles.
Similarities
Mitosis
Diploid parent cell
Consists of interphase, prophase, metaphase, anaphase and telophase
In metaphase individual chromosomes (pairs of chromatids) line up along the equator.
During anaphase the sister chromatids are separated to opposite poles.
Ends with cytokinesis.
Meiosis
Diploid parent cell
Consists of interphase, prophase, metaphase, anaphase and telophase (but twice!)
In metaphase II individual chromosomes (pairs of chromatids) line up along the equator.
During anaphase II the sister chromatids are separated to opposite poles.
Ends with cytokinesis.
Answer:
Some offspring may be tall, some may be short, and some may be medium sized.
Explanation:
My teacher told us the answer.
