evolution chapter 15. what is evolution? evolution, or change over time, is the process by which...

EvolutionEvolutionChapter 15Chapter 15

What is Evolution?What is Evolution?

EvolutionEvolution, or , or change over timechange over time, is , is the process by which modern the process by which modern organisms have descended from organisms have descended from ancient organisms.ancient organisms.

Who is Charles Darwin?Who is Charles Darwin?

Charles Darwin – born in EnglandCharles Darwin – born in EnglandJoined the crew of the Joined the crew of the

H.M.S. BeagleH.M.S. Beagle Sailed Sailed around the worldaround the worldMade numerous observationsMade numerous observations and collected evidence that and collected evidence that led him to propose his led him to propose his hypothesis.hypothesis.

What did Darwin Observe during his voyage?What did Darwin Observe during his voyage?

Patterns of Diversity:Patterns of Diversity:• Puzzled by where different species lived and did not livePuzzled by where different species lived and did not live

• He AskedHe Asked: : * Why were there no rabbits in Australia, despite the * Why were there no rabbits in Australia, despite the

presence of habitats that seemed perfect for them?presence of habitats that seemed perfect for them? * Why were there no kangaroos in England?* Why were there no kangaroos in England? * Why do they look so similar?* Why do they look so similar?

What did Darwin observe during his voyage?What did Darwin observe during his voyage?

Living Organisms & FossilsLiving Organisms & Fossils

• Darwin collected and preserved fossilsDarwin collected and preserved fossils

• FossilsFossils resembled organisms that were still alive – resembled organisms that were still alive – other looked completely unlike any creature he had other looked completely unlike any creature he had ever seen.ever seen.

He AskedHe Asked: Why had so many of these species : Why had so many of these species

disappeared?disappeared?

Looks LIKE a Kangaroo

Looks nothing like any living species

What did Darwin Observe?What did Darwin Observe?

The Galapagos IslandsThe Galapagos Islands

• Most influential place Darwin visitedMost influential place Darwin visited

• Although islands were so close together, the islands had very Although islands were so close together, the islands had very different climates.different climates.

• Fascinated by the land tortoises, marine iguanas, & finches.Fascinated by the land tortoises, marine iguanas, & finches.

Where are the Galapagos Islands?Where are the Galapagos Islands?

A

BC

D

Clicker Question:

What did Darwin observe on the What did Darwin observe on the Galapagos Islands?Galapagos Islands?

Click to zoom into Galapagos Islands

What did Darwin observe on the Galapagos Islands?What did Darwin observe on the Galapagos Islands?

* Domed shell w/ short neck

* Live on wetter islands

* Have short necks that can reach grasses and vegetation on the ground

Galapagos Tortoises


* Flatter shell compared to domed

* Live on slightly drier islands

* Have longer necks than domed to reach short bushes and trees


* “Saddle” w/ VERY long necks

* Live on dry islands

* Dry climates have less vegetation on the ground

* Long neck used to reach vegetation up in bushes & trees growing off the ground

Galapagos Tortoises Galapagos Tortoises


• All tortoises resemble a species living in South AmericaAll tortoises resemble a species living in South America

• Saw that giant tortoises varied in predictable ways from Saw that giant tortoises varied in predictable ways from one island to another.one island to another.

• The shape of a tortoise’s shell could be used to identify The shape of a tortoise’s shell could be used to identify which island a particular tortoise lived.which island a particular tortoise lived.

Natural Selection QuestionsNatural Selection Questions(Bill Nye)(Bill Nye)

1.1. A young man that walked out was __ ___.A young man that walked out was __ ___.2.2. He quit medical school to become a ___.He quit medical school to become a ___.3.3. How long did the Beagle stay in the Galapagos How long did the Beagle stay in the Galapagos

Islands? __ daysIslands? __ days4.4. Finches had different shaped ___: varied by Finches had different shaped ___: varied by

the environment they inhabited.the environment they inhabited.5.5. What was the mechanism that made evolution What was the mechanism that made evolution

occur? ___ ____occur? ___ ____6.6. When did he publish his book?When did he publish his book?7.7. Now, every where we look at today, we see Now, every where we look at today, we see

something that came from ___.something that came from ___.

Natural Selection Clip Natural Selection Clip (Bill Nye)(Bill Nye)

Who influenced Darwin’s ideas?Who influenced Darwin’s ideas?

Recognized that Earth is Recognized that Earth is many millionsmany millions of years old. of years old.

And the processes that changed Earth in the past are And the processes that changed Earth in the past are the same processes that operate in the present.the same processes that operate in the present.

James Hutton and Charles Lyell James Hutton and Charles Lyell

Hutton and Lyell Hutton and Lyell said…said…

Volcanoes release hot lava and gases now, just Volcanoes release hot lava and gases now, just as they did on an ancient Earth.as they did on an ancient Earth.

Erosion continues to carve out canyons, just as Erosion continues to carve out canyons, just as it did in the past.it did in the past.

Also said that awesome geological features Also said that awesome geological features could be built up or torn down over long periods could be built up or torn down over long periods of time.of time. (examples: earthquakes and volcanoes) (examples: earthquakes and volcanoes)

Wild/Crazy Idea:Wild/Crazy Idea: Earth Earth changeschanges over time over time

Hutton and LyellHutton and Lyell

So……Because of Hutton & Lyell’s work…..So……Because of Hutton & Lyell’s work…..

Darwin then askedDarwin then asked: :

If the Earth could change over time, If the Earth could change over time,

might might lifelife change as well? change as well?

Who else influenced Darwin’s Ideas?Who else influenced Darwin’s Ideas?Malthus (an economist) – Studied population Malthus (an economist) – Studied population

growth - observed that babies were being born growth - observed that babies were being born faster than people were dying.faster than people were dying.

He reasoned that if the human population He reasoned that if the human population

continued to grow unchecked, sooner or continued to grow unchecked, sooner or later there would be insufficient living space later there would be insufficient living space and food for everyone.and food for everyone.

Lamarck’s Theory of EvolutionLamarck’s Theory of Evolution

Proposed that by selective Proposed that by selective useuse or or disusedisuse of of organs, organisms organs, organisms acquiredacquired or lost certain traits or lost certain traits during their lifetime.during their lifetime.

These traits could then be passed on to their These traits could then be passed on to their offspring.offspring.

Over time, this process led to change in a speciesOver time, this process led to change in a species

Who else was thinking about evolution?

Was he “right”?

Lets break it down….

How did Lamark think organisms changed?How did Lamark think organisms changed?

Fiddler Crabs: An ExampleFiddler Crabs: An Example

1. The male crab uses its small front 1. The male crab uses its small front claw to attract mates and ward off claw to attract mates and ward off predatorspredators

2. Because the front claw has been 2. Because the front claw has been used repeatedly, it becomes used repeatedly, it becomes larger (acquired).larger (acquired).

3. A larger claw, is then passed on to 3. A larger claw, is then passed on to the crab’s offspring.the crab’s offspring.

He was WRONG! He did not realize He was WRONG! He did not realize that the large claw traits were that the large claw traits were inheritedinherited

Lamark’s Theory Lamark’s Theory

According to Lamarck's According to Lamarck's theory, a given giraffe could, theory, a given giraffe could, over a lifetime of straining to over a lifetime of straining to reach high branches, reach high branches, develop an elongated neck. develop an elongated neck.

The long neck is The long neck is ACQUIREDACQUIRED

Another Example:

The Origin of SpeciesThe Origin of Species

The actual title of his book is:The actual title of his book is:

The Origin of Species by Means of Natural SelectionThe Origin of Species by Means of Natural Selection

• The book proposed a mechanism for The book proposed a mechanism for evolution that he called evolution that he called natural selectionnatural selection..

• He presented evidence that demonstrates He presented evidence that demonstrates the process of evolution has been taking the process of evolution has been taking place for millions of year.place for millions of year. Darwin was 50 when it was

published!

Darwin’s Book

What were Darwin’s arguments in his book?What were Darwin’s arguments in his book?

Natural Variation and Artificial SelectionNatural Variation and Artificial Selection

• Argued that species were Argued that species were NOTNOT perfect and perfect and unchanging.unchanging.

• Natural VariationNatural Variation: There are differences: There are differences

among individuals of a species.among individuals of a species.

What is Natural Variation?What is Natural Variation?

Peppered moths come in two

versions

White Version/Morph

Black Version/Morph

If trees in an area have dark bark, the black version blends in better and is less likely to be eaten by predators.

If trees in an area have white bark, the white version blends in better and is less likely to be eaten by predators.

What is Natural Variation?What is Natural Variation?Bessie Elsie

* Elsie’s natural variation is to produce more milk than Bessie

* Which cow would the farmer use to reproduce offspring? Why?

What were Darwin’s What were Darwin’s arguments in his book?arguments in his book?

Artificial SelectionArtificial Selection: Nature provided the : Nature provided the variation among different organisms, and variation among different organisms, and humanshumans selected those variations that they selected those variations that they found useful.found useful.

* Only the largest hogs, fastest horses, and the * Only the largest hogs, fastest horses, and the cows that gave the most milk were selected to cows that gave the most milk were selected to breed and produce offspring.breed and produce offspring.

Darwin’s Evolution by Natural SelectionDarwin’s Evolution by Natural Selection

The Struggle for ExistenceThe Struggle for Existence: Means that : Means that members of each species compete regularly to members of each species compete regularly to obtain food, living space, and other necessities obtain food, living space, and other necessities of life.of life.

A predator that is the fastest or has a particular A predator that is the fastest or has a particular way of catching prey can catch more prey.way of catching prey can catch more prey.

Prey that are faster, better Prey that are faster, better

camouflaged, or better protected camouflaged, or better protected

avoid being caught.avoid being caught.

Darwin’s Evolution by Natural SelectionDarwin’s Evolution by Natural Selection

Survival of the FittestSurvival of the Fittest: Process by which : Process by which individuals that are better suited to their individuals that are better suited to their environment survive and reproduce most environment survive and reproduce most successfully; also called successfully; also called Natural SelectionNatural Selection..

Darwin called the ability of an individual to Darwin called the ability of an individual to survivesurvive AND AND reproducereproduce in its specific in its specific environment environment fitnessfitness..

An An adaptationadaptation is any inherited characteristic is any inherited characteristic that increases an organism’s chance of that increases an organism’s chance of survival.survival.

Darwin’s Discoveries Video ClipDarwin’s Discoveries Video Clip

Survival of the Fittest Survival of the Fittest

The concept of The concept of fitnessfitness, Darwin argued, was , Darwin argued, was central to the process of evolution by natural central to the process of evolution by natural selection.selection.

Example: Example:

Baby birds compete for food in the nest. The Baby birds compete for food in the nest. The stronger bird may take food from the weaker stronger bird may take food from the weaker siblings. siblings.

Evolution by Natural SelectionEvolution by Natural Selection

Descent with ModificationDescent with Modification: Principle that each : Principle that each living species has descended, with changes, living species has descended, with changes, from other species over time.from other species over time.

• Implies that all living organisms are related to Implies that all living organisms are related to one another.one another.

Common DescentCommon Descent: The principle that says all : The principle that says all species – living and extinct – were derived from species – living and extinct – were derived from common ancestors.common ancestors.

Evidences of Evolution

There are 4 categories

Evidence #1:

FOSSIL RECORD

What are some evidence of Evolution?What are some evidence of Evolution?

Fossil RecordFossil Record

Fossils that had formed in Fossils that had formed in the different layers of rock the different layers of rock were evidence of gradual were evidence of gradual change over time.change over time.

One could view how a One could view how a species had changed and species had changed and produced different species produced different species over time.over time.

Evolution of Horses

- Horses do not look the same as they did many years ago

- Fossil Record shows evidence that animals have changed over time and that they share a common ancestor based on similarities in their skeletons.

Evidence #2:

COMPARATIVE ANATOMY

Homologous StructuresHomologous Structures: Structures that have : Structures that have different mature forms in different organisms different mature forms in different organisms but develop from the same embryonic tissues.but develop from the same embryonic tissues.


Shows that the organisms

are RELATED!

• Analogous structuresAnalogous structures can be superficially can be superficially similar in construction, but are NOT inherited similar in construction, but are NOT inherited from a common ancestor. from a common ancestor.

• ExampleExample: The wing of an eagle & the wing of a : The wing of an eagle & the wing of a insect have the same function (both enable the insect have the same function (both enable the organism to fly) – but are constructed in organism to fly) – but are constructed in different ways & from different materials.different ways & from different materials.


* While analogous structures do not indicate * While analogous structures do not indicate close evolutionary relationships, they do show close evolutionary relationships, they do show that functionally similar features can evolve that functionally similar features can evolve independently in similar environments.independently in similar environments.


Vestigial StructuresVestigial Structures

• Vestigial StructuresVestigial Structures are structures that are the are structures that are the reduced forms of functional structures in reduced forms of functional structures in different species.different species.

ExamplesExamples: :

1. 1. Snake PelvisSnake Pelvis: The pelvis is the attachment : The pelvis is the attachment point for legs and is therefore nonfunctional in point for legs and is therefore nonfunctional in an animal without legsan animal without legs

Vestigial StructuresVestigial Structures2. Kiwi Wing: The wings of kiwis are too small to 2. Kiwi Wing: The wings of kiwis are too small to

be of any use in flightbe of any use in flight

3. Human Appendix: Important for digestion in 3. Human Appendix: Important for digestion in many mammals, but of limited use in humans & many mammals, but of limited use in humans & some apessome apes

Evidence #3:

COMPARATIVE EMBRYOLOGY

Similarities in Early DevelopmentSimilarities in Early Development

In their early stages of development, chickens, In their early stages of development, chickens, turtles, and rats look similar, providing evidence turtles, and rats look similar, providing evidence that they shared a common ancestry.that they shared a common ancestry.


Evidence #4:

COMPARATIVE BIOCHEMISTRY

What we know… All cells rely on DNA to make proteins.

Using new technologies, biologists are able to determine the amino acid sequences in proteins to determine evolutionary relationships among various species of organisms.

The more closely related two species are, the greater the similarity in amino acid sequences of their

proteins.

For example:

Evolution VideoEvolution Video

Types of Evolution

There are 5 main types

Divergent Evolution:When two species move away from the traits that they share with a common ancestor as

they adapt to their own environments

Also called

Adaptive Radiation…

Has

homologous structures,

And are CLOSELY related!

Convergent Evolution:When two distinct species with differing

ancestries evolve to display similar features.

Has

analogous structures,

And are NOT closely related!

Sugar Glider:

Flying Squirrel

Australian marsupial

A GA squirrel

Geographic Distribution of Living SpeciesGeographic Distribution of Living Species

- Species now living on different continents had each descended from different ancestors.

- Because some animals on each continent were living under similar ecological conditions, they were exposed to similar pressures of natural selection.

• They ended up evolving certain striking features in common…

but are NOT related!

• This is called Convergent Evolution

Punctuated EquilibriumEvolution that has long periods of

stability/unchange followed by short periods of rapid change.

Gradualism A change that is very slow over time. Its hard to notice a difference over a short period of time…it is slow and gradual.

Adaptations:Adaptations:A body part, body covering, or A body part, body covering, or

behavior that helps an organism behavior that helps an organism survive its environment.survive its environment.

Biological ResistanceSome organisms have a mutation that makes them resistant to a toxin (antibiotic or pesticide).

Over use of antibiotics & pesticides create populations of “super bugs”.

This is why you need to take your antibiotics for the entire time…

You expose the bacteria to the toxin, if you don’t kill them all (take all your medicine), then you taught them how

to resist the antibiotic!

Adaptations:Adaptations:

MimicryMimicry: Adaptation in which one species : Adaptation in which one species evolves to resemble another species for evolves to resemble another species for protection or other advantages.protection or other advantages.


CamouflageCamouflage: Adaptation : Adaptation

that allows organisms to blend that allows organisms to blend

into their surrounds.into their surrounds.

Plants:Plants:Tropisms (Responses): Tropisms (Responses):

1) Phototropism: Responds to light1) Phototropism: Responds to light


2) Thigmotropism: Responds to touch2) Thigmotropism: Responds to touch


3) Gravitropism: Responds to gravity3) Gravitropism: Responds to gravity

Video Here/Turn volume off!


4) Hydrotropism: Responds to water4) Hydrotropism: Responds to water

CactusCactusRidges:

Expand to store more water when it rains

Thorns:

Protect against being eaten

No Leaves:

Prevent water loss

Waxy Covering:

Prevent water loss

Polar BearPolar Bear

Large Paws:

Walking on snow

Short/small Ears:

Save Heat

Long Claws:

Catching prey/digging

White/clear Fur:

Blend in with snow

Thick Blubber:

Keep warm

Adaptation PosterAdaptation Poster1.) Animal must be drawn, in color, & neat1.) Animal must be drawn, in color, & neat

2.) Must include background environment2.) Must include background environment

3.) Must have at least 5 adaptations w/ explanation 3.) Must have at least 5 adaptations w/ explanation

NotNot adaptations: adaptations:

* How long they live* How long they live

* Where they live* Where they live

* How many babies the have* How many babies the have

* What they eat* What they eat


* Large paws, thick beak, bright colored feathers, * Large paws, thick beak, bright colored feathers, skinny legs, large ears, sharp teeth, fur thickness….skinny legs, large ears, sharp teeth, fur thickness….

The The EndEnd

evolution chapter 15. what is evolution? evolution, or change over time, is the process by which...

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