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Kiosk Notes th 6 Period April 6, 2009 Darwin’s Observations By: Heather Halleen and Stayce Lane Introduction Darwin’s important observations included the diversity of living things, the remains of ancient organisms and the characteristics of organisms on the Galapagos Islands. Diversity Today, scientists knows that organisms are even more diverse than Darwin could ever imagine. A species is a group of similar organisms that can mate with each other and produce fertile offspring. Fossils A fossil is a preserved and remains or traces of an organism that lived in the past. For example, Darwin saw fossils that resembled bones of living sloths. Galápagos Organisms By: Melanie Adelstein and Christine Anton Similarities and Differences The iguanas on the Galapagos Islands, had large claws that helped them grip slippery rocks. The iguanas on the mainland had smaller claws to help them climb trees to get leaves. The tortoises on one island had dome shaped shells and the other island had saddle shaped shells. Adaptations An adaptation is a trait that helps an organism survive and reproduce. Finches’ beaks are an adaptation to maintain food. Adaptations help organisms avoid getting eaten. Example: having a bad taste or being poisonous. Bright colors of flowers help reproduction. Adaptation of a eagle Evolution Ethan Sills, Kayla Sobel, Jillian Barrat Charles Darwin Darwin thought that plants and animals that arrived on the Galápagos Islands faced conditions that were different from those on the mainland. Darwin hypothesized the species gradually changed over many generations and became better adapted to the new conditions. Evolution and Scientific Theory Evolution is the gradual change in a species over time. Scientific theory is a well tested concept that explains a wide range of observations. Darwin then concluded that organisms on the Galápagos Islands had changed over time. But he was still confused how the changes happened. Selective Breeding Darwin studied the offspring of animals that were produced by selective breeding. Darwin himself, bred pigeons with large fan-shaped tails. By doing this he produced pigeons that had two to three times the usually number of tail feathers. Natural selection By:jordyn Lally and Julia Filc Natural selection Natural selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce. The factors that effect natural selection are; overproduction, variations, and competition Overproduction Overproduction is when a species produces so many offspring that there aren't enough resources for them Variations Variations are any differences between individuals of the same species Competition Competition is where members of a species are forced to compete with one another to survive, when resources are limited. Most competition is indirect, where there is no physical fighting. Natural Selection (part 2) Malvi Devanathan and Sari Kowit Selection - variations make individuals better adapted to the environment Over a long period of time natural selection can lead to change Helpful variations may gradually accumulate a species, while some disappear. Environmental Change A change in the environment can affect an organisms ability to survive. The environmental change can therefore lead to selection. Genes and Natural Selection Without variations, all the members of the species would have the same trait. Natural selection would not occur because all individuals would have an equal chance of surviving and reproducing. Variations result from mutation and the shuffling of alleles during meiosis.