Day 13 October 10th Chapter 8 Scribd

8/3/2019 Day 13 October 10th Chapter 8 Scribd

1/29

Day 13 October 10th Chapter 8

How did the second exam go?


2/29

Chapter 8: Evolution and Natural Selection

Darwins dangerous idea: evolution by natural selection

Lectures by Mark Manteuffel, St. Louis Community College ; Clicker Questions by Kristen Curran, University of Wisconsin-Whitewater


3/29


4/29

Evolution in Action

8.1 We can see evolution occurright before us. Therefore,evolution is a scientific process.


5/29

Could you breed fruitflies who could livelonger than 20 hours

on average?


6/29

Populations

are studied


7/29

When these eggs hatch, do you think theflies in this new generation will live longer

than 20 hours without food?


8/29


9/29

What happened?

Evolution

a genetic change in the population

Natural selection the consequence of certain individual organisms in

a population being born with characteristics thatenable them to survive better and reproduce more

than the offspring of other individuals in thepopulation


10/29

Does evolution occur?

The answer is an unambiguous:YES.

We can watch it happen in the labwhenever we want.

Recall from our discussion of the scientific method

that for an experiments results to be valid, they

must be reproducible.


11/29

Experiments in Evolution

Dogs?

Rabbits?


12/29

In Nature -


13/29

Why are camels a successful species?


14/29

Evolution

How does evolution occur?

What types of changes can evolutioncause in a population?

Five primary lines of evidence

Evolution by natural selection


15/29


16/29

Darwins Journey to an Idea

8.2 Before Darwin, most peoplebelieved that all specieshad beencreated separately and wereunchanging.


17/29

Button started the debate by suggesting the Earth

had to be at least 75,000 years old!


18/29

Jean-Baptiste Lamarck

Biologist, early 1800s

Living species might change over time.

(Was wrong about the mechanism - he thought that change came about

through the use or disuse of features)


19/29

Charles Lyell

Geologist

1830 bookPrinciples of Geology Geological forces had shaped the earth and were

continuing to do so.

Gradual but constant change

This idea that the physical features of the earth were constantly changing would most

closely parallel Darwins idea that the living species of the earth, too, were gradually

but constantlychanging.


20/29

We know the Earth is constantly

changing

Fossils of shells have been found high in theAndes Mountains

Forest fires wipe out entire species of plants and

animals. Rivers flow, and carve out rock, creating two

distinct shores, where different species live.

Lakes dry up, killing all marine life inside.

Pollution and Toxic spills kill organisms.

Volcanoes.


21/29

In the 1790s, Georges Cuvier began to explore the bottoms

of coal and slate mines and found fossils


22/29

Why were fossils such a problem for

people at that time?

This was highly troubling for people at the

time.

http://www.bspcn.com/2009/04/03/11-extinct-animals-that-have-been-photographed-alive/


23/29

Extinction

five mass extinctions on earth, and four in thelast 3.5 billion years - many species havedisappeared in a relatively short period of

geological time. The "Great Dying" about 250 million years ago,

which is estimated to have killed 90% of speciesexisting at the time.

Most extinctions have occurred naturally, withouthuman intervention: it is estimated that 99.9% ofall species that have ever existed are now extinct.
http://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_eventhttp://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event


24/29

8.3 A job on a round-the-world surveyship allowed Darwin to indulge and

advance his love of nature.

Age 16, University of Edinburgh, medical studies

Studied theology at Cambridge University

His real love: study of nature


25/29


26/29

Found that he HATED sea

travel

Spent as much time on

shore as possible

Collected fossils and

specimen to bring back to

England

Felt like he was on

permanent vacation


27/29

8.4 Observing geographic similarities anddifferences among fossils and living plants

and animals, Darwin developed a theory ofevolution.

Lyells Principles of Geology

The Galapagos Islands

How could he explain finding marine fossils high in the Andes Mountains,

hundreds of miles from the nearest ocean?

The idea that the earth was an ever-changing planet was seeping into Darwins

mind.


28/29

The Galapagos Islands


29/29

July 1998 (I was a junior in college)

Documents

Day 13 October 10th Chapter 8 Scribd