AP Bio- Evolution 1: Introduction to Evolution

5. Repeat 1-4 every generation over millions of years (Lyell)...

...& life will adapt to the environment .

Any Questions?

Make sure you can

Big Question

How do organisms evolve?

Explain the development of evolutionary theory, the contributions of all people discussed in this presentation, and the evidence that they based their contributions on.

Describe the process of natural selection and give at least three examples of how it can lead to changes in a species.

Compare natural selection with artificial selection.

Explain why the criticisms of evolution discussed in this presentation are the product of faulty reasoning.

Evolution: An Introduction

Brief History

Natural Selection

What did people think about life on Earth 200 years ago?

How it Works:

Some Examples:

Science Does Not Happen In A Vacuum

Artificial Selection

About those finches...

2. Variation among individuals (observation)

1. Overproduction of Offspring (Malthus)

3. Competition for Limited Resources (inference)

What's up with all these fossils?

Flood remnants?

Rock takes a long time to form!

The selective pressure of the Galapagos Environment has driven the evolution of the finches.

Beaks are very important for birds.

Darwin provided a lot of examples of "artificial selection"

Just like natural selection, but "fitness" is determined by human needs/wants.

Big changes can happen very fast.

Darwin didn't freestyle Evolution from nothing.

Thinking about life was pretty standard scientific faire for the 19th century.

Had life always existed as it does now? Was it always changing?

How old was the Earth (Bible: ~7,ooo years old).

No two are quite the same!

Most Babies won't grow up!

How come I don't see any trilobites at the beach?

Why would God kill them all?

It's the "Struggle for Existence!"

The environment determines fitness!

Any birds that survive pass on their beak traits to their offspring.

Repeat for millions of years.

This Was The Thought Stew That Darwin Worked In!

Extinction:

What's the deal with that?

Does God get tired of some organisms?

Isn't God perfect?

Georges Cuvier

Modern Science

Pesticide Resistance

150 years later, we have a mountain of examples of natural selection in action.

In the modern age, the focus has been on quantifying the effects of natural selection on the characteristics of a population.

Take home message: Natural Selection is universal!

Uniformatarianism:

The process happening on Earth now are similar to those that happened in the past

"Principles of Geology": VERY OLD Earth

4. Successful competitors survive, reproduce, & pass on their traits (observation)

Charles Lyell

Life will always adapt if it can.

Spraying of pesticides kills all of the pests who aren't resistant.

The resistant survivors reproduce...

...resistance increases (leading to more spraying, more resistance...)

Thomas Malthus

Jean Baptiste Lamarck

The effect of food type on the length of the beak of the Soapberry bug:

Populations would like to grow forever, but....

Bonsai Tree Babies are Regular Size

1. Life Evolves!

2. Inheritance of Acquired Characteristics!

3. Use and Disuse!

(Only the first bit is right, just ask this guy!)

FITNESS!!!

Similar mechanisms drive the evolution of:

• antibiotic resistance in bacteria
• antiviral resistance in viruses

...Why?

Competition for limited resources!

Darwin: Brief Biography

(1809 - 1892)

Common Ancestry of Life:

A fundamental conclusion of

Natural Selection

If we accept that life evolves, logic suggests that all of life should share a common ancestor.

This is supported by all evidence we have found.

I suggest it is the most amazing thing ever determined about life on Earth.

The Galapagos Islands

A remarkably unspectacular young life.

Comfortable family wealth.

Notoriously undecided about a job

Med school, Parsonage, Naturalist, Whatever.

Family connections got him a gig as the captains companion on the HMS Beagle.

Circumnavigation of the globe!

5 years (22-27)!

Became the ships naturalist.

Read, Collected, Wrote & Thought!

An important stop for Darwin.

Weird, unique animals.

The "A-ha!" Moment:

"Tree Thinking"

The pattern of evolution of life on Earth.

Darwin's Notes:

2 facts, both explained by common ancestry:

Another tree by Ernst Haekel

A modern tree (informed by DNA analysis):

Similarity between fossils and modern organisms

Similarity in skeleton's of 5 great Ape species

"The natural history of these islands is eminently curious, and well deserves attention. Most of the organic productions are aboriginal creations, found nowhere else; there is even a difference between the inhabitants of the different islands; yet all show a marked relationship with those of America, though separated from that continent by an open space of ocean, between 500 and 600 miles in width. ...Hence, both in space and time, we seem to be brought somewhere near to that great fact—that mystery of mysteries—the first appearance of new beings on this earth." -Darwin (Journal entry).

The ultimate tree (DNA again)

The only illustration in "Origin" (1st ed.):

Giant Tortoises!

Marine Iguanas!

All 1 species.

Different shell shapes due to different cactus plants on different islands.

The only swimming lizard in the world!

Algae eaters.

Reaction to the Theory

Scientifically, Evolution is the unifying principle of all other fields of Biological study.

Natural selection (and other modes of evolution) are as close to biological "laws" as anything going.

Finches!

Until...

And Then....

"Knuffke's Law":

Almost entirely, issues with evolution are due to misunderstandings about the Theory:

Public reaction was mixed.

Certain religious perspectives can't reconcile evolution with their modes of thinking.

These are not mainstream religious beliefs.

For whatever reason, it's a particular problem in the US.

There are 12 species of Galapagos Finch.

Different beak structure driven by different feeding behavior.

All share a common imigrant finch ancestor

The only example of natural selection in the "Origin of Species"

"Nothing in Biology makes sense except in the light of evolution"

-Theodosius Dobzhansky

Darwin came home....

...published his journal...

...married his cousin...

...had four children...

...buried one of them...

...did a lot of other work...

...and didn't publish his theory FOR 20 YEARS!

He received a paper from a young naturalist asking for his thoughts on a new theory.

The same theory he had developed 20 years earlier.

Uh Oh.

He wrote a quick paper.

Both papers were published simultaneously.

And Darwin wrote a book.

Probably the most important one ever on Biology.

Introducing a whole new idea about how life evolves

Alfred Russel Wallace

“if we came from apes how come were not hairy and have a big mouth and did we end up looking like we do know and besides there isnt any serious proof of apes they showd a video saying an ape waswondering around in the forest that thing looked exactly like a costume that i had saw at a store know one ever cought an ape”

-From a post on the internet

(sic not mine)