Ecology and Evolution
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IB Biology SL II Ryan Martucci Topic: 4 - Ecology and Evolution Date: 5-24-02 Period: 4th Sub-topic: 4.3 - Evolution 4.3.1 1 Define evolution. Evolution refers to the processes that have transformed life on Earth from its earliest forms to the vast diversity that characterizes it today. 4.3.2 1 State that populations tend to produce more offspring than the environment can support. Populations tend to produce more offspring than the environment can support. 4.3.3 3 Explain that the consequences of the potential overproducing of offspring is a struggle for survival. Natural selection is the unequal ability of individuals to survive and reproduce. But, natural selection occurs through the interaction of the individuals with the environment and favorable variations of individuals. So individuals that have favorable characteristics will stay alive and cause natural selection to take place and reproduce offspring. If there is an overproduction of offspring the species with the characteristics needed to survive and live to the next generation and reproduce.
4.3.6 3 Explain how natural selection leads to the increased reproduction of individuals with favorable heritable variations. Use the Darwin-Wallace Theory. Topic: 4 - Ecology and Evolution Sub-topic: 4.3 - Evolution Page: 3 Charles Darwin theory of natural selection is broken up into three inferences based on five observations. First Darwin found that if all individuals reproduce successfully than the population size would grow exponentially. Second, populations tend to stay stable in size if not disturbed by seasonal fluctuations. Third, environmental resources are limited. From these three major observations he made his first inference that there is more offspring than can survive because of the environmental carrying capacity therefore there is a struggle for existence. An inference he made was that having the ability to survive and reproduce leads to gradual changes in a population, with the favorable traits accumulating over time. He then made two more observations; there is a variation among individuals of a species and many of these variations are inherited.
Before the Industrial Revolution the gray colored moth were the most common because the color enabled them to camouflage themselves against the lichen covered trees, unlike the darker colored moths. However, during the Revolution, the trees became cover in soot, allowing the darker colored moths survive, reproduce, and eventually outnumber the lighter gray colored moths. This is an example of how the peppered moth populations have evolved. Another example of evolution caused my environmental changes is antibiotic resistance to Penicillin caused by overuse and misuse. Penicillin was prescribed to many people to help with various things that Penicillin might not have been necessary for, this mistake was made by doctors over-prescribing it to patients for minor things that could have been cured with other over-the-counter drugs. Topic: 4 - Ecology and Evolution Sub-topic: 4.3 - Evolution Page: 5 Another mistake made by patients using Penicillin is the fact that they would not finish the bottle even if instructed to do so. If the whole amount is not taken, the drug will not work correctly or completely, and will make the body immune to it.
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