1 / 12

Natural Selection

Natural Selection. Evolution. D escent with modification or Change in a population over time S mall-scale or microevolution: changes in gene frequency in a population from one generation to the next

miach
Download Presentation

Natural Selection

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Natural Selection

  2. Evolution Descent with modification or Change in a population over time Small-scale or microevolution: changes in gene frequency in a population from one generation to the next Large-scale or macroevolution: the descent of different species from a common ancestor over many generations. Evolution helps us to understand the history of life.

  3. Natural Selection Natural selection is one of the basic mechanisms of evolution, along with mutation, migration, and genetic drift. Some factor in the Environment selects those individuals that are best suited to their environment to survive and reproduce, thus changing the population over time.

  4. Overproduction of Offspring Organisms tend to produce more offspring than can survive.

  5. Inherited Variation • Offspring are born with different traits (phenotype) because of different gene combinations. • Differences are the result of : mutations, crossing over, and/or independent assortment.

  6. Competition to survive • There is a finite supply of environmental resources like… Food, shelter, mates, water, avoiding predation, sunlight, oxygen, etc.

  7. Adaptation • Those individuals who are born with variations that help them to survive are said to have an adaptation. • Variation is random and so an individual cannot choose to have an adaptation • An advantage in one environment is sometimes a disadvantage in another.

  8. Reproduction Survival of the fittest – those individuals who are better suited to their environment will survive and reproduce most successfully. It is the individual who leaves behind the most offspring who “wins”

  9. Result • Over time traits that lead to more offspring accumulate in the environment and the population becomes better suited to their environment.

  10. Industrial melanism

  11. Activities • Read survival of the sneakiest article and answer the questions http://evolution.berkeley.edu/evolibrary/article/sneakermales_01 • Make a cartoon showing overproduction, variation, finite resources/competition, natural selection/differential survival and reproduction • Peppered moth simulation http://www.biologycorner.com/worksheets/pepperedmoth.html http://peppermoths.weebly.com/

More Related