The Puzzle of Life’s The Puzzle of Life’s Diversity Diversity

Section 15–1 Section 15–1 This section outlines Charles Darwin’s This section outlines Charles Darwin’s contribution to science. It also describes the contribution to science. It also describes the pattern of diversity he observed among pattern of diversity he observed among organisms of theorganisms of theGalápagos Islands.Galápagos Islands.

Introduction Introduction

The process by which modern The process by which modern organisms have descended from organisms have descended from ancient organisms is called .ancient organisms is called .

EvolutionEvolution

Introduction to DarwinIntroduction to Darwin

A well-supported explanation of A well-supported explanation of phenomena that have occurred in phenomena that have occurred in the natural world isthe natural world isa(an) .a(an) .

• TheoryTheory

Introduction to DarwinIntroduction to Darwin

Is the following sentence true or false? Is the following sentence true or false?

• Charles Darwin contributed more to Charles Darwin contributed more to our understanding of evolution than our understanding of evolution than anyone else.anyone else.

TrueTrue

Voyage of the Voyage of the Beagle Beagle

Circle the letter of each sentence that is true Circle the letter of each sentence that is true about Charles Darwin.about Charles Darwin.

a. a. He was born in 1809.He was born in 1809.

b. b. He was an English naturalist.He was an English naturalist.

d. d. The voyage lasted 5 years and took him The voyage lasted 5 years and took him around the world.around the world.

Voyage of the BeagleVoyage of the Beagle

Voyage of the BeagleVoyage of the Beagle

• Is the following sentence true or Is the following sentence true or false? Darwin was looking for a false? Darwin was looking for a scientific explanation for the diversity scientific explanation for the diversity of life on Earth.of life on Earth.

• TrueTrue

Darwin’s Observations Darwin’s Observations

Circle the letter of each Circle the letter of each observation that Darwin made.observation that Darwin made.

An enormous number of species inhabit Earth.An enormous number of species inhabit Earth.

Some species that lived in the past no longer Some species that lived in the past no longer live on Earth.live on Earth.

The preserved remains of ancient The preserved remains of ancient organisms are called .organisms are called .

FossilsFossils

As Darwin studied fossils, As Darwin studied fossils, what new questions arose?what new questions arose?

He wondered why so manyHe wondered why so manyspecies had disappeared and how species had disappeared and how they were related to living species.they were related to living species.

Is the following sentence true or false?Is the following sentence true or false?

Of all the Of all the Beagle’s Beagle’s ports of call, ports of call, the one that influenced Darwin the the one that influenced Darwin the most was the Galápagos Islands.most was the Galápagos Islands.

TrueTrue

Circle the letter of each choice Circle the letter of each choice that is true about the that is true about the Galápagos Islands.Galápagos Islands.

The higher islands have more rainfall.The higher islands have more rainfall.

How did Darwin explain differences in How did Darwin explain differences in shell shape of tortoises from Hood Island andshell shape of tortoises from Hood Island andIsabela Island? Isabela Island?

Darwin thought that Hood Island tortoises had Darwin thought that Hood Island tortoises had curved shells to allow them to reach the curved shells to allow them to reach the sparse vegetation on their island, whereas sparse vegetation on their island, whereas Isabela Island tortoises had dome-shaped Isabela Island tortoises had dome-shaped shells because vegetation on their island was shells because vegetation on their island was more abundant and closer to the ground.more abundant and closer to the ground.

Darwin observed that small brown Darwin observed that small brown birds on the Galápagos Islands birds on the Galápagos Islands differed in thediffered in theshape of their .shape of their .

BeaksBeaks

The Journey Home The Journey Home

What did Darwin think about on his What did Darwin think about on his journey home to England?journey home to England?

Darwin thought about how the Darwin thought about how the characteristics of many animals and characteristics of many animals and plants, including mockingbirds and plants, including mockingbirds and tortoises, varied noticeably among the tortoises, varied noticeably among the different islands of the Galápagos. different islands of the Galápagos.

After he returned to England, what After he returned to England, what hypothesis did Darwin develop to hypothesis did Darwin develop to explain his findings?explain his findings?

• Separate species evolved from a Separate species evolved from a common ancestor after becoming common ancestor after becoming isolated from one another on isolated from one another on different islands of the Galápagos.different islands of the Galápagos.