DARWIN’S VOYAGE OF DISCOVERY

Mrs. MacWilliamsAcademic Biology

I. Darwin’s Voyage

A. Darwin’s Voyage of the Beagle

1. Date: December 27, 1831

2. Ship: H.M.S. Beagle

3. Destination: Voyage around the world.

4. Findings: evidence to propose a revolutionary hypothesis about how life changes over time

**Darwin was only 22 years old

CHARLES DARWIN

5. Geologists suggested Earth was ancient and had changed over time

6. Biologists were suggesting that life on Earth had also changed

The process of change over time is called EVOLUTON

7. Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from COMMON ANCESTORS.

B. Three Patterns of Biodiversity1. Species vary globally

Darwin noticed that different animal species inhabited separate, but ecologically similar, habitats around the globe.

EX: flightless, ground-dwelling birds called rheas live in the grasslands of South America. Rheas look and act a lot like ostriches. Yet rheas live only in South America, and ostriches live only in Africa. The emu is another large flightless bird found in Australia.

EX. Australia’s grasslands were home to kangaroos and other animals that were found nowhere else.

2. Species vary locallyDarwin noticed that different, yet related, animal species often occupied different habitats within a local area.

EX. 2 species of rheas living in South America: one in grasslands and the other in the colder, harsher grass and scrubland

EX. Galápagos Islands giant tortoises. • shape of the tortoises’ shells corresponds to different habitats. • vegetation that is close to the ground tortoise has dome-

shaped shell and short neck. • island that is flat, dry, and has sparse vegetation tortoise has

long neck and curved open shell around neck and legs to reach sparse, high vegetation.

• Darwin also observed that different islands had different varieties of mockingbirds, all of which resembled mockingbirds Darwin had seen in South America.

• In addition, Darwin noticed several types of small brown birds on the islands with beaks of different shapes. He didn’t consider these smaller birds to be unusual or important—at first.

1. Adaptation- a characteristic that helps a plant or animal survive in its environment.

2. Bird beaks have adapted for many things: eating, defense, feeding young, gathering nesting materials, building nests.

3. Size and shape of beak is specific for the type of food the bird gathers.

a) Cardinals

i. heavy thick = crack seeds

Bird Beak Adaptation

b) humming-birdsi. thin = sip nectar

1. FINCHESa) Birds species were similar

but each had specialized beaks for catching food.

E. Galapagos “Darwin’s” Finches

GALAPAGOS FINCHES

Land Tortoises

Marine Iguanas

Blue-Footed Booby

Darwin Finches

Galapagos penguins (yes, penguins)

And many other animals that are not found anywhere else on Earth. Plus, these animals are not afraid of humans (they’ve never seen one!

Animals found in the Galapagos

3. Species vary over time• Darwin collected fossils, which are the preserved remains

or traces of ancient organisms.

• some fossils of extinct animals were similar to living species.

• One set of fossils unearthed by Darwin belonged to the long-extinct glyptodont, a giant armored animal similar to the armadillo. Darwin wondered if the armadillo might be related to the ancient glyptodont.

LET’S SEE IF YOU CAN GUESS WHAT THESE BIRDS EAT BY LOOKING AT THEIR BEAKS

BIRD BEAKS