Natural Selection Study Guide PDF

Natural Selection Study Guide Vocabulary: acquired trait - the character developed in an individual as a result of environmental influence behavioral trait - the characteristics that consistently describe a person's behavior heritable trait - an offspring's...

Natural Selection Study Guide Vocabulary: acquired trait - the character developed in an individual as a result of environmental influence behavioral trait - the characteristics that consistently describe a person's behavior heritable trait - an offspring's trait that resembles the parents' corresponding trait more than it resembles the same trait in a random individual in the population physical trait - observable characteristics that you can see just by looking at a plant, animal, or human advantageous - Some traits make an organism more likely to survive and reproduce in its environment. These are called advantageous traits. For example, advantageous traits often make organisms better at finding food or avoiding predators. Some traits make an organism less likely to survive and reproduce in its environment. Fitness - an organism's ability to pass its genetic material to its offspring probability statement - a measurement tool that calculates the chance or likelihood of occurrence of an event natural selection - the process through which populations of living organisms adapt and change Concepts: 1. Give examples of physical, behavioral, heritable, and acquired traits. a. physical traits examples: skin color, eye color, curly hair b. behavioral traits examples: talkative, energetic, and assertive c. heritable traits examples: tongue rolling, earlobe attachment, dimples d. acquired traits: knowledge, ideas, skills, and weight 2. Explain how sexual reproduction creates genetic variation in a population. a. Fertilization leads to new, diploid offspring. Sexual reproduction results in genetic variation, or genetic differences, between parents and offspring. Offspring inherit one set of chromosomes from each parent. So, an offspring has a mixture of chromosomes (and alleles) from its two parents. 3. Relate all behaviors to an organism’s desire to mate, eat, avoid predators, or raise young. 4. Explain why specific traits are considered advantageous by relating them to how they help an organism survive or reproduce. a. In generation after generation, advantageous traits help some individuals survive and reproduce. And these traits are passed on to greater and greater numbers of offspring. After just a few generations or after thousands, depending on the circumstances, such traits become common in the population. 5. Create probability statements related to organisms’ probability of reproduction or survival in a specific environment with or without a specific trait. a. such as why organisms with less desirable traits are less likely to survive and reproduce in a specific environment than organisms with desirable traits. 6. Explain why genetic variation within a population allows some organisms within the population to be more likely to reproduce or survive. a. If a trait is advantageous and helps the individual survive and reproduce, the genetic variation is more likely to be passed to the next generation (a process known as natural selection) 7. Explain how natural selection allows only the fittest to survive a. being able to avoid predators and other dangers b. Those individual organisms who happen to be best suited to an environment survive and reproduce most successfully, producing many similarly well-adapted descendants. After numerous such breeding cycles, the better-adapted dominate. 8. Give examples of an advantageous trait increasing within a population. a. The surviving beetles (more of which are brown) have offspring of the same color because this trait has a genetic basis. End result:The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. 9. Explain how changes to the environment can affect whether a trait is advantageous. a. Individual organisms with certain traits are more likely than others without these traits to survive environmental changes, and therefore to have offspring; hence the proportion of the population of organisms with these advantageous traits increases. This represents the idea of selection.  10. Explain why, over time, certain advantageous traits increase in a population and why certain disadvantageous traits decrease in a population. Over time, the proportion of individuals with advantageous traits may increase (and the proportion with disadvantageous traits may decrease) due to their chances of surviving and reproducing. Essay Question Topics: : 11. Explain how a trait can affect the probability of an organism’s reproduction and survival in a specific environment. 12. Explain how natural selection leads to increases and decreases of specific traits within a population over time. Research Project: 13. Research how humans around the world have adapted to their environment through natural selection.