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Chapter 14
Evolution: How Change
Occurs
14-1 Developing a Theory of
Evolution
http://www.rtgmin.org/wp-content/uploads/2012/06/evolution-tree.jpg
Evolutionary Theory-a collection of carefully
reasoned and tested hypotheses about how
evolutionary change occurs
http://upload.wikimedia.org/wikipedia/commons/9/97/Darwin's_finches.jpeg
Lamarck idea 1: A desire to
change
https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTY9LwXzfIj5N00LMBtpFbhi0dcHWSXrC4MdniXzxR1FsVg1UySpg
Lamarck idea 2: Use and Disuse
http://api.ning.com/files/STALJJZvzLYwhxeg03-hAPhcQnrycuRcTbdK0wzXtpc1AFvKxyYxLu7*K3iM8FEFCfU0vJkooFNzP34YR78u3ZMui5vC*cbU/giraffe_lamark.jpg?width=300
Lamarck idea 3: Passing on
acquired traits
http://biology.clc.uc.edu/graphics/bio104/lamarck.jpg
Lamarck thought that organisms change because they
have an inborn urge to better themselves and become
fit for their environments.
http://1.bp.blogspot.com/_ACaDF0kiT5I/S9safFMb5yI/AAAAAAAAAUI/UvA7SHFyElY/s1600/giraffe.jpg
Example: Birds are able to fly because
their ancestors desired to fly
http://i.livescience.com/images/i/000/014/314/i02/Avian_Archaeopteryx_02.jpg?1297215075
Change occurred because organisms could alter their shape by
using their bodies in new ways. He also believed that if an animal
did not use a particular part of its body that body part would
decrease in size and might disappear.
http://o.quizlet.com/maf3jjW41FYnld4WhdObuA_m.jpg
He believed they were inherited. That if an
organisms acquired long arms it would pass
those long arms on to its offspring
http://evolution.berkeley.edu/evolibrary/images/history/giraffenecks.jpg
He was the first to devise a theory of
evolution. He also brought it to the
attention of other scientists
http://www.blackwellpublishing.com/ridley/images/lamarck.jpg
We are able to say that only genes are
passed from parents to offspring not
specific body structures.
http://library.thinkquest.org/28599/images/offthemark/testing.gif
Influence of Geology: Lyell’s
Ideas
http://2.bp.blogspot.com/-5f6wRc0YiRs/TVquwtgfWTI/AAAAAAAACf4/9sa87N1_cqU/s1600/Georiddle.jpg
Influence of Farmers: Artificial
Selection
http://evolution.berkeley.edu/evolibrary/images/evo/mustardselection.jpg
Influence of Malthus: Population
Controls
http://cla.calpoly.edu/~lcall/111/malthus.gif
Artificial Selection Picking only
individuals that allow traits that are
wanted
http://www.csus.edu/indiv/l/loom/wk%2015/dogs.jpg
Darwin believed that their was a process in nature that
allowed only the organisms that were best suited with
their environment to survive and reproduce
http://www.biology-online.org/images/darwin_finches.jpg
They are not able to all survive because there are not
enough resources for all of them too. Most of them die
in the first year after they are hatched
http://ssep.ncesse.org/communities/chicago/files/2011/07/Fish-Eggs.jpg
14-2 Evolution by Natural Selection
http://evolution.berkeley.edu/evolibrary/images/interviews/naturalselection1.gif
Natural Selection-Process in nature that
results in the most fit organisms produce
offspring
http://evolution.berkeley.edu/evosite/misconceps/images/misconceptions_beavers.gif
Animals compete for space
http://www.bbc.co.uk/bitesize/standard/biology/images/animal_fight.jpg
Animals compete for food
http://www.eoearth.org/files/119201_119300/119275/250px-Lion_hyena_competition.jpg
Animals compete for water
http://www.fws.gov/endangered/news/images/spring-2010-bushmeat1.jpg
Individuals whose characteristics are well-suited to
their environment survive. Individuals whose
characteristics are not well-suited to their environment
either die or leave fewer offspring
http://www.paranormalocean.com/wp-content/uploads/2012/06/cuttlefishinreef.jpg
Darwin Vs. Lamarck Video
14-3 Genetics and Evolutionary
Theory
What causes genetic variations? What do
these variations have to do with evolution
by natural selection?
How are evolution, fitness, and adaptation
described in genetic terms?
Genes: Units of Variation
Genes allow for random variations which
allows natural selection to happen
Mutation and meiosis account for
variations in genetics
Organisms cannot control their DNA
changing
Genetic Variations
http://studentreader.com/genotypes-phenotypes/
Raw Material for Natural Selection
Natural selection needs phenotypic variation to
operate
Look at all of the phenotypic variations in this
class alone (height, weight, shapes of noses)
Other organisms show this even though we don’t
notice
There are many differences between species
Phenotypic Variation
http://en.wikipedia.org/wiki/Phenotype
Evolution as Genetic Change
Biologists study groups of organisms
called populations
Population-a collection of individuals of
the same species in a given area whose
members can breed with one another
Example: all the fishes of a certain species
in a single pond is one population
http://kimberlynurseries.com/2011/12/02/winterizing-your-fish/
Because all of a population can interbreed,
they share a common group of genes
called a gene pool
Gene pool contains a specific amount of
alleles for each trait
The number of times an allele occurs in a
gene pool compared with the number of
times other alleles for the same gene
occur is called the relative frequency of
the allele
Gene Pool
http://www.brooklyn.cuny.edu/bc/ahp/LAD/C21/C21_GenePool.html
Sexual reproduction alone doesn’t change
relative frequency in a population
Its similar to shuffling a deck of cards, many
combinations but doesn’t change the number of
aces, kings, etc…
Evolution is any change in the relative
frequencies of alleles in the gene pool of a
population
In other words the number of alleles have to
change for a gene pool to change
http://biology.unm.edu/ccouncil/Biology_203/Summaries/PopGen.htm
Genes, Fitness, and Adaptation
Genes get passed to offspring when
organisms reproduce
Evolutionary fitness is the success an
organism has in passing its genes to the
next generation
An adaptation is any genetically controlled
characteristic that increases an organisms
fitness
http://www.exploringnature.org/db/detail.php?dbID=5&detID=3
Example: if a weight lifter exercises a lot
and gets large muscles they do not pass
that on to their offspring
If they have a gene which makes it easier
for them to gain muscles then that can get
passed on to their children
http://www.topendsports.com/image/clipart/fitness/weight-lifting/weight-lifter-strain.gif.php
A Genetic Definition for Species
A species is a groups of similar-looking organisms that
breed with one another and produce fertile offspring
Members of a species share a common gene pool
If there is a genetic change it can pass through the gene
pool
If it increases fitness the gene will eventually be found in
many individuals
This means species evolve together
http://archaeologynewsnetwork.blogspot.com/2011/03/species-disappearance-threat-to.html
14-4 The Development of New
Species
What is a niche?
How do new species develop from existing
species?
What are the results of divergent
evolution? Of convergent evolution?
The development of New Species
Speciation-the process of new species
being created
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Speciation.html
The Niche: How to Male a Living
Organisms need to acquire the necessities
of life (food, water, space)
The combination of what an organism
does and the place in which it occupies is
its niche (example: work place)
If two species share the same niche they
compete for resources there, one species
will not survive
http://www.britannica.com/EBchecked/media/74637/A-pair-of-red-deer-stags-competing-for-possession-of
No two species can occupy the same
niche in the same location for a long
period of time
One of the species will be more efficient
than the other which will allow them to
survive and reproduce
Any species that occupies an unoccupied
niche they will be better able to survive
This can lead to new species
http://www.smartrecruiters.com/blog/5-hot-niche-job-boards/
The Process of Speciation
New species usually form only when
population are isolated, or separated
(remember gene pool and definition of a
species)
This separation of populations so that they
do not interbreed to produce fertile
offspring is called reproductive isolation
http://www.tutorvista.com/content/biology/biology-iv/biotic-community/speciation.php
Reproductive isolation is a reason for the
formation of new species
May result from geographical barriers
which can change ways in which
organisms breed
One isolation occurs natural selection
increases differences between populations
This then alters the genes of isolated
species resulting in new species
http://www.goldiesroom.org/Note%20Packets/21%20Evolution/04%20Evolution--Lesson%204.htm
Darwin’s Finches: An Example of
speciation
Finches in the galapogos were examined
Darwin felt that 13 species evolved and are
different due to geographical barriers and
reproductive isolation
This caused 1 species to evolve into 12
Video
Darwin’s Finches
http://www.biology-online.org/2/11_natural_selection.htm
Speciation and Adaptive Radiation
Adaptive Radiation-when one species
gives rise to many
Also known as divergent evolution
During a period of adaptive radiation,
organisms evolve characteristics that
enable them to survive in their niches
http://www.gambassa.com/public/project/1837/DavidLuoTimeline.html
Adaptive radiations among different
organisms often produce species similar in
appearance and behavior
This is known as convergent evolution
This has produced many of the
analogous structures in organisms today
These are similar in appearance and
function, but they have different origins
Convergent Evolution
http://www.pbs.org/wgbh/evolution/library/01/4/image_pop/l_014_01.html
Analogous Structures
http://eweb.furman.edu/~wworthen/bio111/dar1lec.htm
Analogous structures usually have very
different internal structures
Example: Wings
http://www.bio.miami.edu/dana/106/106F05_4.html
14-5 Evolutionary Theory Evolves
http://images.the-scientist.com/content/images/articles/56251/24-1.jpg
Natural selection is not always necessary for genetic
change to occur. Gene pools can change, evolution
can occur in the absence of natural selection. Chance
plays a larger part
http://waynesword.palomar.edu/images/botneck2.gif
Genetic Drift-Random change in
the frequency of a gene
http://evolution.berkeley.edu/evosite/evo101/IIIDGeneticdrift.shtml
Genetic drift alters the frequency of alleles in a gene
pool. Can happen by a natural disaster or anything
randomly. Usually causes a less popular allele to
become more popular
http://biology.unm.edu/ccouncil/Biology_203/Images/PopGen/bottleneck.gif
All characteristics of an organism do not have to contribute to its
fitness. The rhinos from India have one horn and the rhinos from
Africa have two horns. It is not clear whether having two horns or
one horn increases fitness.
http://2.bp.blogspot.com/-W6M3SMCQid0/ThMsfQOj_fI/AAAAAAAAAAc/3aus45gqT_0/s1600/2.JPG
http://www.defenders.org/sites/default/files/styles/large/public/rhinoceros-guy-standen-dpc.jpg
If the species is well adapted to its environment which
doesn’t change and if there is not competition against
the species the gene pool may not be altered
http://www.rappnews.com/wp-content/uploads/2013/10/wildBeaver-24.jpg
Gradualism- the theory that evolutionary
change occurs slowly and gradually
http://www.amnh.org/learn/resources/evolution_resource1.php
State of equilibrium: It means that the
organisms did not change very much
when they existed
http://casarcia.com/life/ch06/6-1not3.jpg
First, a small population of a species could
become isolated. In small populations, genetic
changes can spread more rapidly.
http://online.santarosa.edu/homepage/cgalt/BIO10-Stuff/Ch13-Evolution/Clicker-Lizard-Population-Isolation-02.JPG
Second, a group of organisms might migrate to
a new environment, where they could rapidly
evolve to fill available niches.
http://1.bp.blogspot.com/-w7R-BP33SMA/UFMIVQvgzuI/AAAAAAAAJJU/z5sseV4_g-c/s1600/4.jpg
Third, the environment could change dramatically and
cause a mass extinction. Such an event would open
up niches for the surviving organisms
http://www.ourbreathingplanet.com/are-we-facing-earths-6th-mass-extinction/
After mass extinctions there are many
empty niches, and these niches can be
filled through adaptive radiations
http://evolution.berkeley.edu/evosite/evo101/images/KTextinction.gif
Punctuated Equilibria-The theory states that evolution
occurs when long periods of relatively little change are
interrupted, or punctuated, by brief periods of rapid
change.
http://withfriendship.com/user/sathvi/punctuated-equilibrium.php