Unit 12 – Intro to Unit 12 – Intro to EvolutionEvolution

Summary color is pink; vocabulary is underlined.

Hyperlinks are in green; they will take to you videos and

animations.

Background Image: http://magickcanoe.com/insects/angry-katydid-3-large.jpg

This katydid is well adapted to look like the leaves of its habitat. In this unit we will discuss theories of evolution and adaptation that lead to such phenomenon within populations.

Background Image: http://magickcanoe.com/insects/angry-katydid-3-large.jpg

SensitivitieSensitivitiess

Due to the sensitive nature of thisunit I ask that we keep in mindthat the theories behind evolutioncan often breed tensions becauseof religious teachings.

These theories are part ofunderstanding the world ofscience. Our scientificdiscussions will focus onattempting to explain naturalphenomena (or events).

Differing religious opinions are okay, but religious based theories on the history of life are not the focus of this class.

Scientific Scientific TheoryTheory

Textbook Reference pg. 18 Textbook Reference pg. 18

• Theory in everyday life is different from the scientific theory – i.e. someone has a theory on who will win the Super Bowl.

• A scientific theory is an explanation of natural and physical phenomena that is supported by a large body of scientific evidence from multiple, independent researchers.

• Unlike hypotheses, theories are well- established and highly reliable – they are subject to change as new information is obtained or technologies developed.

EvolutionEvolutionTextbook Reference pg. 10Textbook Reference pg. 10

• The Earth has millions of kinds of organisms with an amazing amount of diversity, yet, we all share similarities, the core of which is DNA. (Every living organism has it!)

• How are all these different organisms related to each other?

• Evolution, or change in a species over time, is the process by which modern organisms have descended from ancient ones.

• For example, the ancient horse a was about the size of a medium dog!

http://www.eurekalert.org/images/release_graphics/yu0926.jpghttp://www.eurekalert.org/images/release_graphics/yu0926.jpg

Who is Who is CharlesCharlesDarwin?

Textbook Reference pg. 393-396 Textbook Reference pg. 393-396

• The British scientist Charles Darwin is credited the most in our understanding of evolution. After college in 1831, Darwin joined the crew of the ship the H.M.S. Beagle for a voyage around the world (5 years!).

• During his travels, Darwin took observations, specimens, and collected evidence for the variety of species on this planet.

• He later proposed a hypothesis about the way life changes over time .

• That hypothesis, now supported by a larger body of modern evidence, became the theory of evolution.

http://www.anselm.edu/homepage/jpitocch/genbios/22-05-VoyageOfHMSBeagle-L.gif

Darwin Cont.Darwin Cont.

• When the ship was anchored, he collected plant and animal specimens.

• In one single day in the Brazilian rainforest he collected 68 different species of beetles!

• When sailing, Darwin took observations of the organisms and kept detailed notes.

http://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/http://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Striped.love.beetle.arp.jpg/250px-Striped.love.beetle.arp.jpgStriped.love.beetle.arp.jpg/250px-Striped.love.beetle.arp.jpg

Galápagos Galápagos IslandsIslands Textbook Reference pg. 394 Textbook Reference pg. 394

• Probably his most influential location on Darwin’s journey was the Galápagos Islands off the coast of South America; 500 500 miles west of Ecuador in the Pacific miles west of Ecuador in the Pacific Ocean, directly on the equator.Ocean, directly on the equator.

• Although they were very close together (50 to 60 miles and still within eye sight), the islands had very different climates and very different plants and animals living there.

http://www.cnn.com/EARTH/9707/17/Galápagos /Galápagos .lg.jpghttp://www.cnn.com/EARTH/9707/17/Galápagos /Galápagos .lg.jpg

• Darwin learned that each island had a different variety of land tortoises.

• One island turtle has a long neck and curved opening in the shell to allow for the organism to search for food because of sparse vegetation (or plant life).

• Yet, another island with a lot of plant life has a turtle that is very close to the ground the with a short neck making it easier to eat.

http

://up

load

.wik

imed

ia.o

rg/w

ikip

ed

ia/co

mm

ons/a

/a1

/Gal%

C3

%A

1p

ag

os_to

rtoise

_Santa

_Cru

z.jpg

Darwin Darwin Cont.Cont. Textbook Reference pg. 399-400 Textbook Reference pg. 399-400

• In his travels, Darwin compared living organisms to fossil evidence that he collected throughout his voyage.

• A fossil is the preserved remains of an ancient organism.

• Some living organisms he observed looked like preserved fossils, while others were unlike any creature he had ever seen! (EX Dinosaurs)

• His evidence posed more questions.

• Why had so many species disappeared?

• How are ancient organisms related to modern organisms?

http://english.people.com.cn/200406/07/images/0606_112.jpghttp://english.people.com.cn/200406/07/images/0606_112.jpg

On the Origin of On the Origin of SpeciesSpecies Textbook Reference pg. 396 Textbook Reference pg. 396 • Darwin used his notes and

scientific findings to build his theory of evolution; it took him years before he was willing to publish his work because of the drastic controversy it would (and did) cause.

• His book, On the Origin of Species [By Means of Natural Selection] was published in 1859.

• In it he argued that life has been evolving for millions of years.

• His book sold out in the first day and became an instant best seller!

htt

p:/

/rati

onalr

evolu

tion.n

et/

imag

es/

darw

in_a

pe.jp

g

The political cartoon (1861) is The political cartoon (1861) is just one example of the just one example of the negative reaction to the negative reaction to the theories explained within the theories explained within the book.book.

Five Basic Concepts Five Basic Concepts of Natural Selectionof Natural Selection

• Use the chart to list the 5 themes from On the Origin of Species.

1. Variation Among Species1. Variation Among Species Textbook Reference pg. 407,409 Textbook Reference pg. 407,409

• All species have genetic variation (we now know) caused by differences in the DNA and genes of an organism (EX color of fur; shape of teeth; blood type; hormone levels).

• Darwin argued that variation was normal and was important.

• Characteristics vary within a species and this can affect the survival of individuals.

http://www.swarthmore.edu/NatSci/cpurrin1/evolk12/gps/images/saddlestretch.jpg

2. Struggle for 2. Struggle for ExistenceExistence Textbook Reference [Competition] pg. 38-39 Textbook Reference [Competition] pg. 38-39• Organisms produce more offspring than can survive. Organisms produce more offspring than can survive. • Some that survive do not produce offspring.Some that survive do not produce offspring.• Organisms are forced to compete for resources.• This is called the struggle for existence; members of

each species must compete for the necessities of life (food, water, & space).

• Survival affected by short-term natural disasters – EX droughts, fires, floods, snowstorms, hurricanes, etc.

• And affected by long-term changes in the environment – EX ice ages, biome shifts, etc

http://eoimages.gsfc.nasa.gov/images/imagerecords/79000/79553/sandy_goe_2012302_1745_lrg.jpg

3. Adaptations3. Adaptations Textbook Reference pg. 9, 397-399 Textbook Reference pg. 9, 397-399

• Darwin began to realize that organisms have certain characteristics or behaviors that allow them to survive in their environment.

• An adaptation is an inherited characteristic (EX a longer neck) that can increase an organism’s chance of survival.

• If they live long enough, they will reproduce and pass on their genes.

http://www.cedar-foundation.org/uploads/images/300%20Turtle.jpg

http

://ww

w.p

bs.o

rg/w

gb

h/e

volu

tion/lib

rary

/01

/6/im

ag

es/l_0

16

_02

_l.gif

http

://ww

w.p

bs.o

rg/w

gb

h/e

volu

tion/lib

rary

/01

/6/im

ag

es/l_0

16

_02

_l.gif

Textbook Reference pg. 469Textbook Reference pg. 469

Knowledge CheckKnowledge CheckThe diagram below shows features of the varieties of finches in the Galapagos. How can the diagram help us understand the evolutionary terms like variation and adaptation? Turn and talk to your neighbor.

4. 4. FitnessFitness• Some organisms are Some organisms are

more suited to their more suited to their environment due to environment due to natural variationsnatural variations in the in the species.species.

• Darwin used the term fitness to define an individual’s ability to survive and reproduce.

• Individuals that are fit Individuals that are fit to their environment to their environment survive and leave more survive and leave more offspring offspring than those than those who aren’t.who aren’t.

http://farm1.staticflickr.com/49/125046333_7123c38e73_z.jpg?zz=1

5. 5. Descent with Descent with ModificationModificationTextbook Reference [Diagram] pg. 374-375Textbook Reference [Diagram] pg. 374-375

• LivingLiving species today are species today are descended descended (with modifications)(with modifications) from from commoncommon ancestral species ancestral species that lived in the past.that lived in the past.

• Over time, Over time, traits [i.e. genes] traits [i.e. genes] for for lessless favoredfavored characteristics characteristics will will be eliminatedbe eliminated from the gene from the gene pool.pool.

• Species today, therefore, look different from their ancestors because of historical changes.

htt

p:/

/lh4

.gg

pht.

com

/-U

Gl8

KK

cTb

yM

/Tw

v3

HA

UU

fXI/

AA

AA

AA

AA

KPI/

uV

xQ

I5FX

WYo/im

ag

e_t

hum

b3

.png

?im

gm

ax=

80

0

Sketch, Darwin’s Sketch, Darwin’s NotebookNotebookBranching “Tree of Life”Branching “Tree of Life”

Knowledge CheckKnowledge Check

http://www.zo.utexas.edu/faculty/sjasper/images/22.7.gif

The diagram below shows descent with modifications for modern elephants. How can the diagram help us understand evolutionary terminology like variation and descent with modification? Turn and talk to your neighbor.

What is the gist of the What is the gist of the book?book?• Natural selection is the process by which individuals

that are better suited to their environment survive and reproduce most successfully (AKA survival of the fittest).

• Organisms that are well adapted will be able to survive. Over time, natural selection leads to changes in the characteristics of a population.

• New species develop, increasing biodiversity.• Video• Video 2

Artificial Artificial SelectionSelection

Textbook Reference pg. 469Textbook Reference pg. 469

• Darwin understood variation can be a positive thing! • He used the example that a dairy farmer would

benefit from breeding a cow that produces a lot of milk versus a cow that does not.

• He coined the term artificial selection where nature provided the variation and humans selected those variations that are useful (EX a pure breed dog, the best looking horse). Animation

htt

p:/

/ww

w.f

arm

land

-theg

am

e.e

u/im

ag

es/

anim

als

/Dair

y-c

ow

s-p

ict-

1.jp

g

Darwin’s Darwin’s InfluencesInfluences

• Many scientific theories and observations in the years before Darwin helped to influence his theories on evolution.

• Some scientists long before Darwin came to similar conclusions.

• Most people at the time thought Darwin’s opinions too radical (or out there) to accept.http://www.victorianweb.org/science/darwin/darwin_beard.gif

LamarckLamarck

• The French scientist Jean-Baptiste Lamarck was one of the first to recognize that life changes over time.

• He argued that certain traits present in an organism are always passed on to offspring. – EX giraffes stretched their necks to reach food. – Their offspring and later generations inherited the

resulting long necks. • Although some of his theories were flawed, the idea that

species change and adapt greatly influenced the theory of evolution.

htt

p:/

/en.w

ikip

ed

ia.o

rg/w

iki/File

:Jean-b

ap

tist

e_l

am

arc

k2

.jp

g

HuttonHutton• In 1795, the geologist James In 1795, the geologist James

Hutton published his hypothesis Hutton published his hypothesis on the Earth’s geology formed on the Earth’s geology formed very slowly over time, millions of very slowly over time, millions of years and are shaped by natural years and are shaped by natural forces (mainly the weather). forces (mainly the weather).

• Most Europeans at the time Most Europeans at the time believed that the Earth was only believed that the Earth was only a few thousand years old, but a few thousand years old, but Hutton proposed that the Earth Hutton proposed that the Earth had to be much older. had to be much older.

• If the Earth were millions of If the Earth were millions of years old, it would help to years old, it would help to explain the SLOW process of explain the SLOW process of evolutionary change. evolutionary change. http://upload.wikimedia.org/wikipedia/http://upload.wikimedia.org/wikipedia/

commons/thumb/0/0e/commons/thumb/0/0e/Hutton_James_portrait_Raeburn.jpg/220px-Hutton_James_portrait_Raeburn.jpg/220px-

Hutton_James_portrait_Raeburn.jpg Hutton_James_portrait_Raeburn.jpg

LyellLyell • Lyell’s book was published just before Darwin set sail in the Beagle.

• In his book, Lyell proposed that scientists can observe the processes that shaped the Earth millions of year ago in the present (volcanoes, earthquakes, etc. all change how the world looks).

• Darwin wondered if the Earth can change over time, can species change too?

htt

p:/

/ww

w.a

nse

lm.e

du/h

om

ep

ag

e/jp

itocc

h/g

enb

ios/

22

-x3

-Lyell.

jpg

htt

p:/

/ww

w.a

nse

lm.e

du/h

om

ep

ag

e/jp

itocc

h/g

enb

ios/

22

-x3

-Lyell.

jpg

WallaceWallace Textbook Reference pg. 396,468 Textbook Reference pg. 396,468

• A contemporary (same time A contemporary (same time frame) of Darwin, Alfred frame) of Darwin, Alfred Wallace wrote an essay on Wallace wrote an essay on evolution and the process of evolution and the process of natural selection using his natural selection using his studies of plants and animals studies of plants and animals a year before Darwin a year before Darwin published published OriginsOrigins. .

• Darwin and Wallace both Darwin and Wallace both presented their findings at the presented their findings at the same scientific conference. same scientific conference.

• Darwin is remembered while Darwin is remembered while Wallace is often forgotten. Wallace is often forgotten.

http://io.uwinnipeg.ca/~simmons/16cm05/1116/22-x5-AlfredWallace.jpg http://io.uwinnipeg.ca/~simmons/16cm05/1116/22-x5-AlfredWallace.jpg

ExtinctionExtinction Textbook Reference pg. 115 Textbook Reference pg. 115

• Extinction: the destruction of a population.

• IfIf an entire an entire population of population of a a species cannot species cannot adapt, that species adapt, that species becomes extinct.becomes extinct.

• 99% of all species that have ever lived are now extinct!

• Humans contribute to the extinction of many plants and animals because of pollution, loss of habitat, and poaching.

http://www.chrismadden.co.uk/eco/mammoth.gif http://www.chrismadden.co.uk/eco/mammoth.gif

• Many scientists say that the Many scientists say that the earth is currently earth is currently experiencing a experiencing a mass extinction mass extinction crisis.crisis.

• It is estimated that It is estimated that 1/5 or more of the world’s species will 1/5 or more of the world’s species will become extinctbecome extinct if the rainforests alone are destroyed. if the rainforests alone are destroyed.

Indian tigers, for Indian tigers, for example, are a group example, are a group of tiger species that of tiger species that had an original range had an original range from India along Asia's from India along Asia's Pacific rim to northern Pacific rim to northern China as well as other China as well as other sections of Central sections of Central Asia. Their range today Asia. Their range today outside of protected outside of protected areas has been areas has been severely limited.severely limited.

"Fragmented Habitat." "Fragmented Habitat." Science OnlineScience Online. Facts On File, Inc. Web. 30 Jan. 2013. <http://www.fofweb.com/activelink2.asp?. Facts On File, Inc. Web. 30 Jan. 2013. <http://www.fofweb.com/activelink2.asp?ItemID=WE40&SID=5&iPin=SciIllus04661&SingleRecord=True>. ItemID=WE40&SID=5&iPin=SciIllus04661&SingleRecord=True>.

Mass ExtinctionMass Extinction Textbook Reference pg. 378 Textbook Reference pg. 378

• There have been There have been at least 5 at least 5 mass extinctions during mass extinctions during Earth’s historyEarth’s history, when a , when a huge % of the living huge % of the living species were destroyed.species were destroyed.

• At least one At least one of these has of these has been been attributed to meteor attributed to meteor impact impact and it’s and it’s consequences.consequences.

• AnimationAnimation

Photo courtesy of Donald E. Davis, Photo courtesy of Donald E. Davis, also in public domain from NASA.also in public domain from NASA.

Analyzing the Analyzing the GraphicGraphic

Chicxulub Crater, Mexico's Yucatan Peninsula180 kilometre (112 mi) diameter  Most scientists now agree that this event 65 million years ago that marked the sudden extinction of the dinosaurs as well as the majority of life then on Earth.

ConclusionConclusion• Evolutionary theory is

constantly changing due to new information that is obtained.

• EX The AIDS virus is changing constantly, and the flu vaccine must be modified each year due to changes.

• Species change, evolve, over time, and that time is now.

http://evolution.berkeley.edu/evolibrary/images/news/avianswineflu.gif http://evolution.berkeley.edu/evolibrary/images/news/avianswineflu.gif