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