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DSW

DSW. Why are species on the Galapagos so diverse?. Nowhere to Hide. The concept of Natural selection. Individual organisms of the same kind differ in characteristics Name some characteristics Sometimes these differences give individuals an advantage in surviving and reproducing

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DSW

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  1. DSW • Why are species on the Galapagos so diverse?

  2. Nowhere to Hide The concept of Natural selection

  3. Individual organisms of the same kind differ in characteristics • Name some characteristics • Sometimes these differences give individuals an advantage in surviving and reproducing • Individual organisms of different kinds are more likely to survive and have offspring because of particular traits • Small differences between parent and offspring accumulate (through selective breeding) in successive generations • Resulting in descendants that are very different from their ancestors

  4. Evolution • The occurrence of new traits in a population and their effect of these traits on long-term survival • Environmental conditions • Develop new traits because they need to survive • Over-use or under-use certain body organs or abilities • Chance alone-mutations • Produce new heritable characteristics by: • forming new combinations of existing genes-crossing over • Mutations of genes • Modifies an individual’s life • Affects one's germ cells and as a result their offspring

  5. Changing a population results from the survival of a few individuals that reproduce, not from the gradual change of the individuals in the population • Non-inherited traits vs inherited traits

  6. Two distinct processes in evolution • Occurrence of new traits in a population • Environmental • Survival • Over-use/under-use • Genetic mutations • New combinations of genes- crossing over • New traits have an effect on long-term survival • Populations change or adapt over generations inadvertently, not deliberately! • Adaption is NOT a conscious process, it is reactive to the environment!

  7. No Where to Hide • PURPOSE • To understand the concept of natural selection.

  8. No Where to Hide Lesson • MOTIVATION • Write down what you think "survival of the fittest" means. 

  9. Development • Watch the Natural Selection Movie and answer the questions on your student sheet • https://www.youtube.com/watch?v=F6NarClv3CU

  10. Interactive • This interactive is based on the story of the peppered moths that lived in the forests of Manchester England in the 1800s and were affected by a rise in pollution (read the Learn More section). In this activity, you will be able to observe the process of natural selection by changing the amount of pollution in an environment (i.e., the background color of the screen) and then observing its effects on the survival of the green and orange bugs. The student sheet includes both instructions on how to play the interactive activity and questions regarding the activity (the Nowhere to Hide teacher sheet has the answers to these questions). Students can find the answers to the questions in the activity and the Learn More section.

  11. The diagram below illustrates the change that occurred in the frequency of phenotypes in an insect population over 10 generations. A probable explanation for this change would be that over time there was

  12. The diagram below illustrates the change that occurred in the frequency of phenotypes in an insect population over 10 generations. A probable explanation for this change would be that over time there was Ans: Certain traits of a species will become more abundant if they benefit the species. In this case, having spots must camouflage the insect, therefore the gene responsible for the spotting, a, will increase over time in the population.

  13. Assessment • Main point is to understand the concept of natural selection, including “survival of the fittest” • Get into groups of no more than 2 • Come up with an explanation of natural selection and what “survival of the fittest” means • Share out to the class

  14. Natural Selection • From PBS Evolution • “Natural selection is a process where individuals in a population who are well adapted to a particular set of environmental conditions have an advantage over those who are not so well adapted. The advantage comes in the form of survival and reproductive success. For example, those individuals who are better able to find and use a food resource will, on average, live longer and produce more offspring than those who are less successful at finding food. Inherited traits that increase individuals' fitness are then passed to their offspring, thus giving the offspring the same advantages. This is also known as "survival of the fittest"! • Come up with another activity that would demonstrate the process of natural selection. What other scenario could you create and how would it work?

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