Darwin’s Theory Ch. 6 Section 1

Learning Target I can describe important observations Darwin made on his voyage and explain how natural selection leads to evolution.

Charles Darwin Darwin was 22 years old when he set sail on the British ship HMS Beagle in A naturalist on the ship. (someone who studies the natural world). Observed many types of plants and animals and wondered why they were so different from the plants and animals in England. Led to the theory of Evolution by Natural Selection.

Darwin’s Observations Included… Diversity of living things, remains of ancient organisms, and characteristics of organisms on the Galapagos Islands.

Diversity and Fossils Darwin Noticed that animals were diverse and that they adapted to the environment in which they lived in. Fossil- preserved remains or traces of an organism that lived in the past.

Galapagos Organisms Many similarities were found between the Galapagos Organisms and the South American Organisms. (plants and animals) There are differences too. Ex. Galapagos iguanas have longer claws than South American. > This is so they can grip on the slippery rocks on the cost.

Adaptations Finches beaks varied between islands. Some had narrow beaks for eating insects Others had wide beaks for eating seeds. Adaptation: trait that helps an organism survive and reproduce.

Evolution When animals arrived on the Galapagos Islands they had to adapt to new conditions and environment. The species gradually changed over many generations.

Natural Selection Darwin’s Book “the Origin of Species” proposed that evolution occurs by means of natural selection. Natural Selection: process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species.

Natural Selection with turtles Overproduction: Turtles lay many eggs, not all of the young survive. Variation: each turtle has slightly different traits. Competition: turtles compete with one another. A faster turtle may escape a predator. Selection: variation such as speed make some turtles better able to survive in their environment. Survival and Reproduction: only few turtles survive long enough to reproduce. The offspring may inherit the favorable traits of the parents.

Learning Target I can describe important observations Darwin made and explain how natural selection leads to evolution.