1. There is variation in traits. Ex. Some beetles are green and some are brown. 2. Some organisms are better suited to survive and therefore reproduce more. Ex. Green beetles tend to get eaten by birds and therefore reproduce less than brown beetles.
We the Galapagos Islands 3. There is heredity. Ex. The survivng brown beetles have babies with the same beneficial trait. 4. End result: The better trait, brown, allows the beetles to reproduce more therefore making the population of brown beetles more numerous than green beetles, eventually all beetles will be brown.
We the Galapagos Islands Darwin’s Finches • Darwin also collected finches, birds, matching their beak and body shapes with different islands- just like the tortoises. • Beak shapes in the finches indicated their type of diet , what they ate, and this told him where they lived Ground finch Tree Finch In other words, if you get separated from your own species, you evolve or change in response to your environment. Box 9 The finches of the Galapagos Islands provide a classic example of Adaptive Radiation —the evolutionary process through which a single lineage gives rise to species occupying diverse environmental niches . In one model of how species form, geographical separation leads to evolutionary divergence (growing apart). Box 10 and 11
We the Galapagos Islands Darwin’s Finches FYI, each beak is designed for a different purpose. Leaves Seeds Insects Grubs Tool using Seeds and Fruit Box 12
We the Galapagos Islands Use it or lost it Hi! I’m Crabby. I want to be superior, how can I do that? I know! I’ll grow a huge claw, and I’ll squash those other crabs! Look, it’s Crabby, what a jerk. Hey, Crabby, you loser! Let’s drop him! You just wait! I’ll get you one day! Stay away from me! Ha Ha! Are you scared? Huh? Are you scared you little twerps! The Next Day…… Where are you going? Run away! Run away! Boy, dad sure did know what he was doing when he developed this huge claw- weapon! Yeah, thanks dad! Eeek! It’s the C Gang, they won’t leave me alone! Oh, I’ve GOT to grow that claw!
We the Galapagos Islands Artificial Selection and Natural Selection • Variation exists in nature and animal and plant breeders use this through artificial selection – A farmer may like a see a plant with bigger tomato and use the seeds of that plant for next year’s crop – Or he may breed the two best milk cows to get a cow who is an even better producer of milk • Darwin’s greatest contribution was his concept of natural selection • In the struggle for survival, the most fit - the fastest prey, the strongest predator, the one with the sharpest claws, wins the game of survival. Survival of the fittest. • Fitness = the ability to survive and reproduce in a specific environment How is your fitness?
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