Topic 1-Evolution And Natuarl Selection Flashcards
What is natural selection?
Is the generally accepted mechanism for the evolution of new species. As a result of natural selection, animals and plants become better adapted to their environment.
What is evolution?
Is the gradual change is species over time, resulting in the formation of new species and the extinction of some others.
What is the theory of natural selection?
1) Population of all living organisms show variation. Heritable variation is the basis of evolution.
2) Not all individuals in a population can survive, so there is competition for survival
3) Some variants within a population will be better adapted to the environment, and will be better equipped to survive. This is sometimes called survival of the fittest.
4) Those that survive long enough to breed will pass on their genes to the next generation.
5) as the individual who are better adapted have a better chance of survival, their gene is more likely to be passed on.
6) the next generation will have more individuals with better adapted genes.
7) Over a long period of time, the population becomes better and better adapted to their environment, provided the environment does not change.
8) Organisms that are less well suited to their environment, or that cannot adapt quickly enough when the environment changes, will become extinct.
Give an example of evolution
1) some rats are naturally resistant to warfarin.
2) when warfarin was used, only the resistant rags survived.
3) warfarin was used so much that nearly all the non-resistant rats were killed, leaving only the resistant ones.
4) warfarin resistance is genetic, so the offspring rats were mostly resistant.
5) the same process occurred over several generations, until nearly all rats in the UK population were warfarin-resistant.
Why are scientists worried that similar thing may happen if we keep using the same antibiotics to treat diseases?
The evolution of resistance to antibiotics in bacteria.
