EVOLUTIONEVOLUTION

What is it?What is it?

MISCONCEPTIONSMISCONCEPTIONS

““Evolution is like a climb up a ladder of Evolution is like a climb up a ladder of progress; organisms are always getting better.”progress; organisms are always getting better.”

““Evolution is a theory about the origin of life.”Evolution is a theory about the origin of life.”

““Evolution means that life changes by Evolution means that life changes by chance.”chance.”

MISCONCEPTIONSMISCONCEPTIONS

““Evolution is Evolution is justjust a theory.” a theory.”

““Gaps in the fossil record disprove evolution.”Gaps in the fossil record disprove evolution.”

THEORYTHEORYEveryday Usage vs. Scientific UsageEveryday Usage vs. Scientific Usage

An An everyday theory everyday theory can be defined as a guess can be defined as a guess or hunch.or hunch.

A A scientific theoryscientific theory is defined as explanations is defined as explanations of natural phenomena built up logically from of natural phenomena built up logically from testable observations and hypotheses.testable observations and hypotheses.

EVOLUTIONEVOLUTION The theory of evolution explains the The theory of evolution explains the

diversity of life and how life has diversity of life and how life has become what it is today. become what it is today.

It It doesdoes notnot explain the origin of life. explain the origin of life.

EVOLUTION EVOLUTION Evolutionary Theory states:Evolutionary Theory states:

All life forms (species) have developed from other species.  All life forms (species) have developed from other species. 

All living things are related to one another to varying All living things are related to one another to varying degrees through common descent (share common degrees through common descent (share common ancestors).  ancestors). 

The process by which one species evolves into another The process by which one species evolves into another involves random inheritable genetic mutations (changes), involves random inheritable genetic mutations (changes), some of which are more likely to spread and persist in a some of which are more likely to spread and persist in a gene pool than others. These mutations can be an advantage gene pool than others. These mutations can be an advantage to an organism and its ability to survive!to an organism and its ability to survive!

But…But…

We can ask ourselvesWe can ask ourselves How did it happen?How did it happen? Who or what does it happen to?Who or what does it happen to? Why does it happen?Why does it happen? How long does it take to happen?How long does it take to happen?

Let’s look at the evidence that drives EvolutionLet’s look at the evidence that drives Evolution

Peppered MothPeppered Moth

TWO FLAVORS OF GALAPAGOS TORTOISE HAVE EVOLVED= Natural Selection

GALAPAGOS FINCHES EXHIBIT ADAPTIVE RADIATION

Leaf MantisLeaf Mantis

THE GALAPAGOS ISLANDS:

HOW BOOBIES, FINCHES, AND PIRATES SHAPED SCIENTIFIC HISTORY

WHERE ARE THEY?WHERE ARE THEY?

WHAT’S IT LIKE THERE?WHAT’S IT LIKE THERE?

WHY ARE THE ISLANDS WHY ARE THE ISLANDS THE THE PLACE TO STUDY PLACE TO STUDY EVOLUTION?EVOLUTION?

WHO EVOLVED? WHO CAN WE OBSERVE?WHO EVOLVED? WHO CAN WE OBSERVE?

WHAT WAS I DOING THERE?WHAT WAS I DOING THERE?

WHERE ARE THE GALAPAGOS ISLANDS?

WHAT’S IT LIKE THERE?

BOOBIES CO-EVOLVED AND OCCUPY DIFFERENT

NICHES

MARINE IGUANAS HAVE ADAPTATIONS FOR LIFE ON THE

SALTY SHORE

SAILORS BROUGHT GOATS THAT OUTCOMPETE NATIVE TORTOISES

INVASIVE RED QUININE OUTCOMPETES NATIVE VEGETATION

EVOLUTIONEVOLUTIONCharles DarwinCharles Darwin

Took a five year voyage around Took a five year voyage around the world (1831-1836) on the H. the world (1831-1836) on the H. M. S. Beagle as the ship M. S. Beagle as the ship Naturalist. Naturalist.

Collected animal specimens and Collected animal specimens and observed patterns of diversity.observed patterns of diversity.

Collected fossils of ancient Collected fossils of ancient organisms.organisms.

Visited Galapagos Islands. Visited Galapagos Islands. Observed that although close Observed that although close together, the islands had very together, the islands had very different climates. The different climates. The characteristics of many animals characteristics of many animals and plants varied among the and plants varied among the different islands. different islands.

Evolution definitionEvolution definition

Changes that occur Changes that occur in populations over in populations over timetime

Evolution by Natural SelectionEvolution by Natural Selection

Natural SelectionNatural Selection: Individuals that have : Individuals that have physical or behavioral traits that better suit physical or behavioral traits that better suit their environment will be more likely to their environment will be more likely to survive AND reproduce!survive AND reproduce!

AdaptationAdaptation: an inherited trait that has become : an inherited trait that has become more common in a population because the trait more common in a population because the trait provides an advantage.provides an advantage.

PBS Video: Darwin’s Dangerous PBS Video: Darwin’s Dangerous IdeaIdea

Natural Selection examples:Natural Selection examples: hummingbirds and mantishummingbirds and mantis HIV virusHIV virus Darwin's evolution gameDarwin's evolution game Peppered mothPeppered moth