chapter 22. Descent with modification: a Darwinian view of life

Q. what is adaptation?


characteristics of organisms that enhance their survival and reproduction in specific environments


Q.what is natural selection?


a process in which individuals with certain inherited traits leave more offspring than individuals with other traits


Q.what is artificial selection?


humans have modified other species over many generation by selecting and breeding individuals that possess desired traits.


facts


1. Evolution, in its most general sense, is simply successive change that occurs over time


2.Evolution only occurs when there is a change in gene frequency within a population over time


3.Darwin addressed the sweeping issues of biology: the great diversity of organisms, their origins and relationships, their similarities and differences, their geographical distribution, and their adaptations to the surrounding environment


4. As all the modified descendants from a common and widely-diffused species, belonging to a large genus, will tend to partake of the same advantages which made their parent successful in life, they will generally go on multiplying in number as well as diverging in character


5.Natural selection, however, is not a random process. It is an ordering process, creating structure from noise and increasing the degree of regularity in the biological system.






diagram
descent with modification. the most striking differences among them are their beaks which are adapted for specific diet. the finches' various beaks and behaviors are adapted and Darwin realized that explaining such adaptations was essential to understanding evolution.

video

http://www.youtube.com/watch?v=CWtCakPk9eM

summary

Charles Darwin was the leading transmutationist of the nineteenth century

The fundamental basis of evolution is that present life forms are descended from primitive ancestors and that the process was guided by natural selection. Creationists and Intelligent Design proponents attack evolution by attacking the concept of natural selection. However, even if it could be done, disproving natural selection does not automatically disprove descent with modification. How evolution occurred and whether it occurred are two separate concepts.