Variation and Natural Selection Notes

1. Variation and Natural Selection Notes Charles Darwin Mutations Variations Natural Selection Adaptations Selective Breeding Evolution How Does All of This Fit Together?

2. Variation and Natural Selection Notes Charles Darwin Scientist during the 1800’s that traveled around the world making observations of nature. Darwin discovered from his travels that organisms have structural characteristics that enable them to live in their environment – Adaptations! Background Information

3. Variation and Natural Selection Notes Darwin’s Finches As Darwin was observing birds on the GalapagosIslands, he discovered that there weremany variations of one kind of bird – the Finch. Variations are differences in form of an organism within the same species or group. Background Information

4. Variation and Natural Selection Notes Darwin’s Finches (Continued) These birds that would later become nicknamed as “Darwin’s Finches” proved that organisms adapt to live in their environment. Each of Darwin’s Finches have a beak that is specifically designed to eat the type of food that is available in its environment. Background Information

5. Variation and Natural Selection Notes Darwin’s Finches (Continued) Each one of these Finches was found on a different Galapagos Island. This illustration shows how various Finches adapted to eat the type of food available to them. Background Information

6. Variation and Natural Selection Notes How Do Adaptations Come About? How Do Adaptation Come About?

7. Variation and Natural Selection Notes Mutations A mutation is where there is a random change in genetic information in an organism. Mutations can be good and they can be bad. If a mutation is good, it will help and organism to live. If a mutation is bad, it will often cause the organisms to die. How Do Adaptations Come About?

8. Variation and Natural Selection Notes Mutations Good or Beneficial Mutations Below is a picture of a Black Jaguar (Left). This color mutation is good because it helps the Jaguar to hunt at night, blending into the night time landscape. How Do Adaptations Come About?

9. Variation and Natural Selection Notes Mutations Bad or Harmful Mutations Below is a picture of a two headed calf . This type of mutation is bad because the animal is not able to survive. How Do Adaptations Come About?

10. Variation and Natural Selection Notes Variations Good mutations lead to variations. When mutations are good, the organism survives to pass the mutation on to it’s offspring. As more and good mutations are passed on, more variations of a species become present as in these parakeets below. How Do Adaptations Come About?

11. Variation and Natural Selection Notes Natural Selection Mutations which lead to variations also lead to naturalselection. Natural selection occurs when good mutations are passed on to offspring. Natural selection is often referred to as “SurvivaloftheFittest”. Organisms that have “stronger” mutations or characteristics survive and the organisms that have “weaker” characteristics die. The organisms with the stronger characteristic are able to pass their stronger characteristics on to their offspring. The organisms with the weaker characteristics die and are unable to pass their weaker characteristics on. How Do Adaptations Come About?

12. Variation and Natural Selection Notes Natural Selection Example How Do Adaptations Come About?

13. Variation and Natural Selection Notes Natural Selection Example (Cont.) How Do Adaptations Come About?

14. Variation and Natural Selection Notes Natural Selection Example (Cont.) How Do Adaptations Come About?

15. Variation and Natural Selection Notes Adaptations Over very long periods of time, the good mutations that get pass on and on over several generations become known as adaptations. Adaptations take hundreds, thousands, or even millions of years to come about. If an organism is not able to adapt, it will die. If an entire species is unable to adapt, the whole species will die and become extinct. How Do Adaptations Come About?

16. Variation and Natural Selection Notes Selective Breeding Selective breeding is when animals are bred on purpose to bring about desired traits. Below is a picture of a horse (left) and donkey (middle) and a mule (right). When a horse is bred with a donkey a mule is produced. A mule has the strength of a horse and the sure footedness of a donkey. How Do Adaptations Come About?

17. Variation and Natural Selection Notes Selective Breeding Selective breeding is when animals are bred on purpose to bring about desired traits. Below is a picture of a horse (left) and donkey (middle) and a mule (right). When a horse is bred with a donkey a mule is produced. A mule has the strength of a horse and the sure footedness of a donkey. How Do Adaptations Come About?

18. Variation and Natural Selection Notes Selective Breeding Selective breeding can also bring about bad or undesirable traits Some breeds of dogs are selectively bred for their aggressiveness, however, this sometimes produces dogs are too aggressive an cannot be controlled. How Do Adaptations Come About?

19. Variation and Natural Selection Notes Evolution Evolution is the end product of adaptations. As mutations, variations, natural selection, and adaptations occur, organisms continue to change to become ever better suited for their environment. How Do Adaptations Come About?

20. Variation and Natural Selection Notes Evolution The evolution of the horse. The modern day horse may have looked something like a dog, but over millions of years of natural selection and adaptations, this animal changed into what we now know as a horse. How Do Adaptations Come About?