Lesson Overview Darwins Voyage of Discovery Lesson Overview

Lesson Overview Darwin’s Voyage of Discovery Lesson Overview 16. 1 Darwin’s Voyage of Discovery

Lesson Overview Darwin’s Voyage of Discovery THINK ABOUT IT q If you’d met young ____________, you probably wouldn’t have guessed that his ideas would change the way we look at the world. As a boy, Darwin wasn’t a star student. q Yet Charles would one day come up with one of the most important scientific theories of all time.

Lesson Overview Darwin’s Voyage of Discovery Darwin’s Epic Journey q ___________ was born in England on February 12, 1809. He grew up at a time when the scientific view of the natural world was shifting dramatically. q Geologists were suggesting that Earth was ancient and had _________________, and biologists were suggesting that life on Earth had also changed. q The process of change over time is called _____. q Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through ____________________________________________________.

Lesson Overview Darwin’s Voyage of Discovery Darwin’s Epic Journey q Darwin was invited to sail on ___________ five-year voyage mapping the coastline of South America. q Darwin planned to ___________________ on the voyage. q No one knew it, but this would be one of the most important scientific voyages in history.

Lesson Overview Darwin’s Voyage of Discovery Observations Aboard the Beagle q Darwin filled his notebooks with observations about the ______________________ of the different species he saw. q Darwin wanted to explain the ___________ he observed in a scientific way. He looked for larger patterns into which his observations might fit. q As he traveled, Darwin noticed three distinctive patterns of biological diversity: q(1) ______________ q(2) ______________ q(3) ______________

Lesson Overview Darwin’s Voyage of Discovery Species Vary Globally q Darwin noticed that different, yet ____________, animal species inhabited separated, but ecologically similar, habitats around the globe. q For example, Darwin found flightless, grounddwelling birds called _______ living in the grasslands of South America. Rheas look and act a lot like ________. Yet rheas live only in South America, and ostriches live only in Africa. When Darwin visited Australia’s grasslands, he found another large flightless bird, the ______.

Lesson Overview Darwin’s Voyage of Discovery Species Vary Globally q Darwin also noticed that rabbits and other species living in European grasslands were __________ from the grasslands of South America and Australia. q Australia’s grasslands were home to _________ and other animals that were found nowhere else. q What did these patterns of geographic distribution mean?

Lesson Overview Darwin’s Voyage of Discovery Species Vary Locally q Darwin noticed that different, yet related, animal species often ____________________ within a local area. q For example, Darwin found ______________ living in South America: one in Argentina’s grasslands and the other in the colder, harsher grass and scrubland to the south.

Lesson Overview Darwin’s Voyage of Discovery Species Vary Locally q Other examples of local variation came from the _________, about 1000 km off the Pacific coast of South America. q These islands are close to one another, yet they have different ecological conditions. Several islands were home to distinct forms of _______________. q Darwin saw differences among the giant land tortoises that inhabit the islands and learned from the islands’ governor that the tortoises’ shells ______ in predictable ways from one island to another.

Lesson Overview Darwin’s Voyage of Discovery Species Vary Locally q The shape of the tortoises’ shells corresponds to different _________. q Isabela Island has high peaks, is rainy, and has abundant __________________. q A tortoise from Isabela Island has ______________________________.

Lesson Overview Darwin’s Voyage of Discovery Species Vary Locally q Hood Island, in contrast, is _______________. q A _______ and a ________________ around the neck and legs allow the Hood Island tortoise to reach sparse, high vegetation.

Lesson Overview Darwin’s Voyage of Discovery Species Vary Locally q Darwin also observed that different islands had different varieties of ______________, all of which resembled mockingbirds Darwin had seen in South America. q In addition, Darwin noticed several types of small brown birds on the islands with _______________. He didn’t consider these smaller birds to be unusual or important— at first.

Lesson Overview Darwin’s Voyage of Discovery Species Vary Over Time q Darwin also collected ________, which are the preserved remains or traces of ancient organisms. q Darwin noticed that some fossils of ________ were similar to _________.

Lesson Overview Darwin’s Voyage of Discovery Species Vary Over Time q One set of fossils unearthed by Darwin belonged to the long -extinct _______, a giant armored animal similar to the ________. Darwin wondered if the armadillo might be related to the ancient glyptodont. q Why had glyptodonts disappeared? And why did they resemble armadillos?

Lesson Overview Darwin’s Voyage of Discovery Putting the Pieces of the Puzzle Together q On the voyage home, Darwin thought about the patterns he’d seen. Darwin sent plant and animal specimens to experts for _______. q The ______________ turned out to belong to three separate species found nowhere else. q The little brown birds were actually all ___________, also found nowhere else, though they resembled a South American finch species. q The same was true of ___________________, and many plants that Darwin had collected on the islands.

Lesson Overview Darwin’s Voyage of Discovery Putting the Pieces of the Puzzle Together q Darwin began to wonder whether different Galápagos species might have evolved from ______________ ancestors. q He spent years actively researching and filling notebooks with ideas about species and evolution. q The evidence suggested that species are not fixed and that they _____________________.