Presentation on theme: "Aim: What is the theory behind life’s great diversity ? Key Idea 3 Individual organisms and species change over time. Objective: Explain how the three."— Presentation transcript:
Aim: What is the theory behind life’s great diversity ? Key Idea 3 Individual organisms and species change over time. Objective: Explain how the three processes of Evolution worked together to yield our present organisms
Evolution is the change of species over time. The diversity of life (millions of different species) on Earth today is the result of natural selection occurring over a vast amount of geologic time The origins of evolutionary thought was laid during the 1700s and 1800s. Charles Darwin Evolution: Who Was Charles Darwin?Evolution: Who Was Charles Darwin?
Section 15-1 On a five-year voyage on the Beagle, Charles Darwin visited several continents and many remote islands. Darwin’s observations led to a revolutionary theory about the way life changes over time.
Pinta Island Intermediate shell Pinta Isabela Island Dome-shaped shell Hood Island Saddle-backed shell Hood Floreana Santa Fe Santa Cruz James Marchena Fernandina Isabela Tower Giant Tortoises of the Galápagos Islands Section 15-1
On relatively dry islands, tortoises with long necks had a slight edge over the tortoises with slightly shorter necks -- long necks, and the notch in their shell that allows them to fully stretch it, allow an individual to reach the foliage on the plants that grow on the island Hood Island Tortoise
Isabella Island Tortoise This Tortoise has traits that helped the animal survive on an Island with lush, low vegetation
Darwin’s Book On the Origin of Species Based on Darwin’s travels and observations, he proposed a mechanism for evolution that he called Natural Selection..