Darwin’s Voyage

POINT > Define biological evolution POINT > Describe Darwin’s voyage on the HMS Beagle POINT > Identify Darwin’s observations on his trip POINT > Summarize Darwin’s observations POINT > Identify how Darwin’s thinking changed after his voyage

Evolution is the process by which organisms and species have changed over time

Darwin set sail on HMS Beagle The Beagle set out to map the coastlines of South America and Australia

Darwin set sail on HMS Beagle Darwin was brought along as a “naturalist”: someone to observe and collect specimens

Darwin noticed patterns of diversity Species vary… 1. Globally 2. Locally 3. Over Time Darwin also noticed geologic events

WB CHECK: What is the name of the ship Darwin was on? How long was Darwin’s voyage on the Beagle? What was the purpose of the Beagle’s trip? What was Darwin’s job on the Beagle?

Species vary globally 1. Different, yet ecologically similar, animal species inhabit ecologically similar habitats around Earth Similar species inhabit similar habitats!

Species vary globally Ostrich (Africa) Rhea (S. America) Emu (Australia)

Species vary globally Flightless birds Old-world vs. New-world Monkeys Big Cats (Jaguar vs. Leopard)

Species vary globally 2. Some species inhabit a ecological habitat, but are not found in a similar habitat in other areas around Earth i.e. some species are unique to specific habitats…

Species vary globally Rabbit (Most of World, except Australia) Kangaroo (Austrailia) Anteater (S. America)

WB CHECK: When Darwin compared similar habitats in S.America, Australia and Africa, he noticed a) the species were very different b) the same species were found in similar habitats c) there was no real pattern in the types of species d) similar species were found in similar habitats

Species vary locally Different, yet related, animal species often occupy different habitats within a local area

Species vary locally Rhea americana Rhea pennata

Species vary locally Mainland Iguanas Marine Iguanas Land Iguanas

Species vary locally Galapagos Islands ~1000km off coast of Ecuador Islands are close to one another, yet have different ecological conditions

Species vary locally Galapagos tortoises Isabela: Larger island with highlands Humid with low-growing vegetation… Tortoise has shorter neck Dome-back (Isabela) Saddle-back (Española)

Species vary locally Galapagos tortoises Española: Smaller island, no highlands Dry with less vegetation… Tortoise has longer neck Dome-back (Isabela) Saddle-back (Española)

Species vary locally Galapagos Finch beak shapes Beaks differ based on food source available on each island

Species vary locally Finch beak shapes Differ based on food source available on the island

WB CHECK: In the Galapagos Darwin noticed a) tortoises with more limited food supply had longer necks b) finches had different beaks depending on which island they were on c) the species were identical to those on the mainland d) the islands all had similar habitats e) all of the above f) a and b g) a,b, and c

WB CHECK: Where are the Galapagos islands? Why are the beaks of finches different on each island? Why do the tortoises on Isabela Island have shorter necks?

Species vary over time Some fossils of extinct animals are similar to living species

Species vary over time Glyptodonts vs. Armadillos Glyptodon / Glyptodont

Species vary over time Glyptodonts vs. Armadillos

Species vary over time Megatherium vs. Tree Sloths Megatherium

WB CHECK: Comparing fossils with living organisms, Darwin noticed that a) species are identical over time b) extinct species may be similar to living species c) extinct species have no resemblance to living species

Geologic Events Earthquakes caused shifting of coastal land masses in Chile Darwin found marine fossils thousands of feet up on mountains

WB CHECK: Darwin made hypotheses about the geological evidence he saw. These hypotheses were probably influenced by a) Carolus Linnaeus b) Jean Baptist Lamarck c) Charles Lyell d) Erasmus Darwin

Darwin saw many fossils of organisms that no longer existed Darwin noticed that slight differences between species reflected the demands of environmental conditions Similar ecosystems sometimes, but not always, had similar species

POINT > Identify how Darwin’s thinking changed after his voyage Darwin, like everyone else, had viewed species as “fixed”. He now concluded this was not the case Darwin noticed that the environment seemed to shape species (like Lamarck suggested) Darwin believed that similar species must have had a common ancestor Darwin needed a way to explain what he saw

Read pages Assess #1-3 page 453 Green Workbook Page 321 Green Workbook Page 323 at least 100 words (2 pts on next exam) Due Tuesday