Darwin’s Theory of Evolution by Natural Selection 15.1

Charles Darwin English Biologist Collected fossils, plants, rocks, and animals while doing research in the Galapagos Islands. Before his research, the planet was thought to only be about 6000 years old and that plants/animals never changed.

Charles Darwin While exploring the Galapagos islands, Darwin observed each island had its own slightly different variety of animals. Almost every specimen Darwin brought back to England was new to English scientists. Darwin suspected that populations from the mainland changed after reaching the Galapagos islands.

Natural Selection V. Artificial Selection The idea of directed breeding to produce offspring with desired traits. Ex: breeding a Labrador retriever with a poodle to get a curly, long haired dog called a labradoodle. The idea that, if left unchecked, undesirable traits within the human population will slowly be weeded out due to their inability to compete to survive. Reproducing without interference. Ex: giraffes with short necks are no longer in existence because they couldn’t compete with long-necked giraffes for food in high places.

Darwin’s principles of Natural Selection Individuals in a population show differences , or variations. Variations can be inherited, passed down from parent to offspring. Organisms have more offspring than can survive on a available resources. Variations that can increase reproductive success will have a greater chance of being passed on than those that do not increase reproductive success.

Darwin’s theories explained Individuals in a population show differences , or variations. Variations can be inherited, passed down from parent to offspring. Organisms have more offspring than can survive on a available resources. Variations that can increase reproductive success will have a greater chance of being passed on than those that do not increase reproductive success. Basically, not all offspring will be able to survive because there aren’t enough resources for every offspring to survive. Only those that have favorable variations will survive. Eventually, the unfavorable variations will be weeded out as those carrying those variations will die and not pass on their variations. This could eventually lead to the creation of a new, more favorably varied species which is unique from the original.

Evolution Evolution- cumulative changes in groups of organisms over time. Ex: people grow in size and mentality over time from birth to adulthood. Evolution DOES NOT mean humans came from monkeys!!!

Key points Charles Darwin completed the original research that suggested that organisms change over time. These changes can lead to the creation of new species. These changes over time are referred to as evolution. Evolution is not the idea that humans came from monkeys.