Ch 14/15 Lecture

Evolution the Theory

First Spontaneous generation

____ experiment

____________ Experiment

History

________ experiment

First Organisms

____________

CyanobacteriaMade Oxygen

_____________ Theory

Aristotle and the Judeo-Christian culture ________ that species are fixed

Fossils suggested that life forms change– This idea was embraced by ________ in the

early 1800s

A sea voyage helped Darwin frame his theory of

evolution

While on the voyage of the HMS Beagle in the 1830s, Charles Darwin observed– similarities between ______ and fossil

organisms– the diversity of life on the Galápagos

Islands, such as blue-footed boobies and giant ________

The voyage of the ________

NorthAmerica

Great Britain Europe

Africa

Equator

Australia

Tasmania

NewZealand

Cape ofGood Hope

SouthAmerica

An

des

Cape Horn

Tierra del Fuego

GalápagosIslands

PacificOcean

AtlanticOcean

Darwin became convinced that the Earth was old and continually _______

– He concluded that living things also change, or evolve over generations: _______ advantage

– He also stated that living species descended from earlier life-forms: descent with __________

Natural Selection________ of the ________

–Organisms which reproduce add to gene pool & __________

Darwin observed that – organisms produce more ________ than the

environment can support– organisms vary in many __________– these variations can be _________

Darwin proposed natural selection as the

mechanism of evolution

DARWIN’S THEORY AND THE MODERN SYNTHESIS

Darwin concluded that individuals best suited for a particular environment are more likely to survive and reproduce than those less well ________

Darwin saw natural selection as the basic mechanism of evolution– As a result, the proportion of individuals

with __________ characteristics increases– Populations gradually change in response

to the ___________

Darwin also saw that when humans choose organisms with specific characteristics as breeding stock, they are performing the role of the environment– This is called ________

selection– Example of artificial

selection in plants: five vegetables derived from wild _________ Figure 13.4A

– Example of artificial selection in animals: dog __________

German shepherd Yorkshire terrierEnglish springer

spanielMini-dachshund Golden retriever

Hundreds tothousands of years

of breeding(artificial selection)

Ancestral dog

These five canine species evolved from a common ancestor through natural selection

___________ radiation

African wilddog

Coyote Fox Wolf Jackal

Thousands tomillions of years

of natural selection

Ancestral canine

Evolutionary adaptations have been observed in populations of birds, insects, and many other organisms– Example: camouflage adaptations of

mantids that live in different environments

Connection: Scientists can observe natural selection in

action

The evolution of insecticide resistance is an example of natural selection in action

Chromosome with geneconferring resistanceto insecticide

Additionalapplications of thesame insecticide willbe less effective, andthe frequency ofresistant insects inthe populationwill grow

Survivor

Insecticideapplication

The excessive use of _________ is leading to the evolution of antibiotic-resistant bacteria– Example:

Mycobacterium tuberculosis

Connection: The evolution of antibiotic ___________ in bacteria

is a serious public health concern

A species is a group of populations whose individuals can ________ and produce ______ offspring– Human populations tend

to concentrate locally, as this satellite photograph of North America shows

The modern synthesis connects Darwin’s theory of natural selection with population genetics

Figure 13.6

Hardy-Weinberg _________ states that the shuffling of genes during sexual reproduction does not alter the proportions of different alleles in a gene pool– To test this, let’s look at

an imaginary, ________ population of blue-footed boobies

The gene pool of a nonevolving population remains constant over

the generations

Webbing No webbing

We can follow alleles in a population to observe if Hardy-Weinberg equilibrium exists

Phenotypes

Genotypes

Number of animals(total = 500)

WW

320

Ww

160

ww

20

Genotype frequencies 320/500 = 0.64 160/500 = 0.32 20/500 = 0.04

640 W 160 W + 160 w 40 w

800/1,000 = 0.8 W 200/1,000 = 0.2 w

Number of allelesin gene pool(total = 1,000)

Allele frequencies

Recombinationof alleles fromparent generation

Next generation:

Genotype frequencies

Allele frequencies

SPERM EGGS

0.64 WW 0.32 Ww 0.04 ww

0.8 W 0.2 w

WWp2 = 0.64

WWqp = 0.16

Wwpq = 0.16

wwq2 = 0.04

W sperm

p = 0.8

w sperm

q = 0.2

W e

gg

p = 0

.8

w egg

q = 0

.2

The population is very _____ The population is _______ ________ do not alter the gene pool Mating is _________ All individuals are _______ in

reproductive success

______ conditions are required for Hardy-

Weinberg equilibrium

Divergent Evolution: _________ structures

Vestigial structure: _________ Evolution

Analogous Structures– similar structures with different origins

Used to fly but not made of the same stuff.

__________ Evolution

Evolution has generally been thought of as a very _______process– However, examples of rapid evolution

have been observed

Evolution Underground

One example of rapid evolution occurred among mosquitoes who ______ into the London underground

In less than 150 years, Culex pipiens evolved into a new mosquito species, Culex molestus

The origin of new species is called ________

The isolated mosquitoes adapted to their new underground environment

– They altered their __________________ ________________________________

___________ barriers that isolate populations are just one of many mechanisms in the evolution of species

When a population is cut off from its parent stock, species evolution may occur– An ______ population may become

_________ unique as its gene pool is changed by natural selection, genetic drift, or mutation

– This is called _________ speciation

Geographic isolation can lead to speciation

MECHANISMS OF SPECIATION

On the Galápagos Islands, repeated isolation and adaptation have resulted in _________ radiation of ____ species of Darwin’s finches

Islands are living laboratories of speciation

__________ radiation on an island chain

Species Afrom mainland

1

A

2B

B

3BC 4

C

C5

BC

D

C D

Niche

Every organism has a specific “______” and “____”

No two species can hold the same niche in the same place for a long period of time

______ driftRandom Change in Gene pool frequency

1 or 2 humps or tusks

Genetic drift is a change in a gene pool due to chance– Genetic drift

can cause the _____________

– Hunting to extinction can cause bottleneck

There are several potential causes of microevolution

Originalpopulation

Bottleneckingevent

Survivingpopulation

_________ and _________ reproductive barriers prevent individuals of different species from interbreeding

Reproductive barriers keep species separate

_____________ in blue-footed boobies is an example of one kind of prezygotic barrier, behavioral isolation

Many plant species have flower structures that are adapted to specific pollinators– This is an example

of _________isolation, another prezygotic barrier

Hybrid sterility is one type of postzygotic barrier

– A horse and a donkey may produce a hybrid offspring, a mule

– Mules are _______

Sexual selection leads to the evolution of secondary sexual characteristics– These may give individuals an advantage

in mating

Sexual selection may produce sexual

___________

How fast is Evolution?

How fast is evolution?

Slow!!!__________– over billions of years slow changes

How fast is evolution?

Fast!!!____________ equilibrium

– short periods of quick change

How fast is evolution?

Fast!!! _____________– death of many species opened space for new ones