Biology 102Lecture 3Outline of Last LectureI. DarwinII. Evolving TraitsIII. FossilsOutline of current Lecture:I. Clicker QuestionsII. Examples of Evolving Traits in AnimalsIII. MicroevolutionClicker Questions1. Natural selection works on heritable variations within populations. How do these variations arise?a. They are acquired during a lifetimeb. Sexual reproduction creates genetic variation in offspringc. Mutations create changes in DNA which result in genetic variationd. All of the above- correct answer(s): B and C- Evolution is an indirect result. The traits that succeed in an environment usually are exclusive to that environment.2. A person is taking antibiotics to fight an infection. In response to the antibiotic, some bacteria become resistant in order to survive in the presence of the antibiotic.a. Trueb. False- Correct answer: false- The bacteria don’t develop a resistance. They either have a gene that leads to them surviving or not. The one who survive pass along that gene to their offspring.Examples of Evolving Traits in AnimalsEvery environment is unique. So in every environment different traits or skills are useful. What may make you the strongest in one environment, can make you extremely weak in a different one.- For example, the leaf mantid in Costa Rica; its entire appearance blends with the leaves it lives on. The flower mantid in Malaysia also blends in to the flower it lives on. Because their appearance matches their environment they are overlooked andBiology 102easily escape predators. However, if the two insects were to switch they would easilystand out. The trait that succeeds in their environment fails in another. Why because that trait is environment specific. - Current Day Evolution- Pesticides: Insects initially were killed by the pesticide used for farming. The ones who did not have the gene for resistance died. The ones who survive reproduce and pass the gene along to their offspringo So the population of resistant insects grows over timeMicroevolutionGene pool: not an individual organism’s genes, it’s when you’re looking at a population- Microevolution- it’s the change over time in the gene pool- 3 main causes:1. Natural selection Different success for offspring in population2. Genetic drif Change in allele frequency that’s up to chanceo Causes the “bottleneck” effect Bottleneck effect- when a population drastically dwindles rapidly in size (ex. fires, earthquakes, floods, human hunting)3. Gene flow Movement of individuals between
View Full Document
Unlocking...