posted by Mohammad on .
my sister still be sick so i still helping her post questions.
i write paragraph from her textbook that go with question.
Ultimately, Darwin recognized in nature a process that operates in a manner similar to the way artifical selection worked on farms and in fields. Darwin called this process natural selection and explained its action in terms of several important observations.
Darwin observed that wild animals and plants showed variations just as domesticated annimals and plants did. his field notebooks were filled with records of height, weight, color, claw size, tail length, and other characteristics among members of the same species. Darwin did not understand the reasons for these variations, but he realized that many of them were inherited.
Darwin observed that high birthrates and a shortage of life's necessities forced organisms into a
constant "struggle for existence," bith against the environment and against each other. Plant stems grow tall in search of sunlight; plant roots grow deep into the soil in search of water and nutrients. Aniimals compete for food and space in which to build nests and raise young. But who among all the contenders wins the struggle for existence?
Darwin knew that each individual differs from all the other members of its species. Sometimes the differences are easy to observe; sometimes the differences are subtle. Individuals whose characteristics are well-suited to their environment survive. Individuals whose characteristics ar not well-suited to their environment either die or leave fewer offspring. This principle Darwin called survival of the fittest.
Natural selection thus operates in much the same way as artificial selection, but over much longer periods of time and without control or direction On a farm, cows that give more milk and corn plants with bigger ears are intentionally selected to be parents to the next generation. In nature, the struggle for existence permits only those individuals well-suited to their environment to survive and reproduce. The fact that less-fit individuals of a species do not survive helps keep the species from covering the Earth.
the question be
what is natural selection? what observations directed darwn to develop this concept?
my sister get first part and she write natural selection is process in nature that results in most fit organisms producing offspring.
she not get the second part because there be too much to add. how to simplify?
wild animals and plants show a lot of variations between individuals
high birth rates and lack of food and water caused organisms to struggle for existence
This site may help you.
thanks very much ms. sue :)
You're welcome, Mohammad.