5.4: An introduction to the
Theory of Evolution
What do we need to know
about Evolution (Weds)?
 5.4.1: Define Evolution
 5.4.2 Outline the evidence for evolution (X4)
 5.4.3: State that populations tend to produce more
offspring than the environment can support
 5.4.4. Explain that one of the consequences of
potential ovrpopulation is a struggle for survival
What do we need to know
about Evolution (Thurs)?
 5.4.5. State that the members of a species show
variation
 5.4.6. State how sexual reproduction promotes
variation in a species
 Explain HOW natural selection leads to evolution
 Explain two example o evolution in response to
environmental change
Objectives for today
 Meet Charles Darwin and his world-changing
‘theory’….
5.4.1: Define Evolution
5.4.2: Outline the evidence for
evolution provided by the fossil
record, selective breeding of
domesticated animals and
homologous structures
‘Isn’t Evolution “just” a theory?’
Darwin’s Theory of Evolution
 "the single best idea anybody ever had” (Daniel Dennet,
Philosopher)

“a big idea, arguably the
(Richard Dawkins, Philosopher)

“Its
most powerful idea ever “
publication (The Origin if Species) changed the
world”
5.4.1: Define Evolution
Synonyms for Evolution
 Charles Darwin used ‘Descent with modification’
 ‘Survival of the fittest’
 ‘Theory of Natural selection’
Richard Dawkins’ Theory of
Evolution
‘Given sufficient time, the non –random
survival of hereditary entities (which will
occasionally miscopy) will generate
complexity, diversity, beauty and an illusion
of design so persuasive that it is almost
impossible to distinguish from deliberate
intelligent design’
Hypothesis vs. Theory
 What’s the difference?.....
 http://www.youtube.com/watch?v=85diEXbJBIk&featur
e=youtu.be
(6 minutes)
Let’s begin by meeting Charles
Darwin…
 http://www.youtube.com/watch?v=vmphlbRhLu8&featur
e=youtu.be
(6.40 mins)
Evolution in a nutshell: The
Tree of Life
 Wellcome Tree of Life
 http://www.wellcometreeoflife.org/
Homework:
Charles Darwin
 Now that you have
background on Charles
Darwin read the short packet
and answer the questions.
 Natural Selection: The
survival and reproduction of
individuals with favorable
heritable traits.
 Empirical Evidence: the
record of one's direct
observations or experiences
Friday
1. The Evidence for Evolution
2. How does natural selection actually
work?
 Examples of natural selection in action: antibiotic
resistance, rodenticide resistance, pesticide
resistance…
Opponents to The Theory of
Evolution: The Blind Watchmaker
oh yeah, it's David Attenborough again...
Evidence for Evolution
 1. The Fossil Record
 2. Artifical Selection – breeding of plants and domestic
animals
 3. Geographical Distribution
 4. Homologous Structures
Evidence for Evolution 1: The
Fossil Record
The Fossil Record
 Palaeontologists uncover
fossilised remains in
sedimentary rock deposits
and use the information to
create timelines
 Organic matter trapped in
sand/ silt/fossils
 Compressed over time
 Dated by isotopic carbon
(50,000 years), potassium40
(1.28 Billion years), 238
Uranium
 Oldest fossils are at the
bottom, youngest at the top
Other methods for dating
fossils
 Dating Methods
Fossil Evidence for Evolution
http://www.pbs.org/wgbh/evolution/sex/mating/index.html
Evidence for Evolution 2:
Homologous structures
 Homologous traits have
similar embryological origins
and development
 Indicative of common
acnestry: what Darwin called
‘Unity of Type’
 Indicative of adaptive radiation
 Pentadactyl limb
 Human appendix
 Whale pelvic and thigh bone
Homologous structures:
Pentadactyl Limb
Homologous structures:
Whale Pelvic bone
Homologous structures:
Human appendix
Evidence for evolution 3:
Artificial Selection
Evidence for evolution:
Artificial selection
Evidence for evolution:
Geographical Distribution
 Before humans arrived, Australia had > 100 types of
marsupials, but no placental mammals
 Hawai’I and New Zealand had unique biotic
environments – plants, insects, birds but no placental
mammals
Evidence for Evolution:
Observable Changes
 Development of new species is RAPID in species with
a short reproductive cycle: bacteria, viruses, parasites,
moths etc etc etc
Week 5: October 2 - 5
 TEST on populations and evolution: Friday or Monday?
The Mechanism of Evolution:
Natural Selection
Hummingbirds and natural Selection
How does natural selection
work?
1. Too many offspring
2. Natural genetic variation
3. Struggle for survival
4. Differential survival and reproduction
Too many offspring
 Results in competition for available resources – food,
shelter, mates, water, sunlight
Natural Variation: Prokaryotes
 Bacteria and other primitive organisms reproduce
asexually
 May change their genetic make-up by means of
mutation
 May change their genetic makeup by means of plasmid
transfer
Natural Variation: Eukaryotes
Mutation
Sexual Reproduction
 Mutations can result in
A much more powerful source
of
combination,
since
thousands of genes are
mixed and copied
advantageous
disadvantageous
changes
or
 In each generation, only
a few genes mutate,
and most mutations
produce effects that are
neither good or harmful
 MEIOSIS
 CROSSING
OVER
in
prophase 1
 Random
assortment
of
chromosomes in metaphase
1
 RANDOM FERTILISATION
 http://i-biology.net/ibdpbio/05-ecology-andevolution/evolution/
 Slide 14 – 27
 http://www.pbs.org/wgbh/evolution/library/01/2/quicktim
e/l_012_02.html
Peppered Moth simulation
 Peppered moth simulation
Your evolution Assignments:
for Thursday
 On the syllabus for 5.4.8, it says "Explain two examples
of evolution in response to environmental change; one
must be antibiotic resistance in bacteria. “
 Your job is to find information on another example of
evolution in response to environmental change. You
should be prepared to share with the class a brief summary
that includes: what organism was affected, what caused
the change, and what the change was.
 !
Group 1: Antibiotic Resistance
in Bacteria
Group 1 will look at develop of antibiotic resistance against
tuberculosis
Resources:
 http://www.sumanasinc.com/scienceinfocus/sif_antibiotic
s.html
 http://www.who.int/topics/tuberculosis/en/
 http://www.euro.who.int/en/what-we-do/healthtopics/communicable-diseases/tuberculosis
 http://www.guardian.co.uk/world/2012/mar/25/drugresistant-strains-of-tb
 http://www.cdc.gov/tb/
Group 2: Pesticide Resistance
Group 2 will look at development of pesticide
resistance in rodents
Resources:
 http://www.mhhe.com/biosci/esp/2001_gbio/folder_
structure/ev/m2/s1/evm2s1_6.htm
 http://www.pbs.org/wgbh/evolution/library/10/1/l_10
1_02.html
 http://evolution.berkeley.edu/evolibrary/article/agric
ulture_04
Group 3: Development of
resistance in Malaria parasites
Group 3 will look at development of drug resistance in
Malaria parasites (and also look at evolutionary
strategies being used to combat malaria!)
 http://www.bbc.co.uk/news/health-17628172
 http://www.thelancet.com/journals/lancet/article/PIIS01406736(12)60484-X/abstract
 http://online.wsj.com/article/SB100014240527023038154045773357
03043691304.html
 http://www.who.int/drugresistance/malaria/en/
 http://www.who.int/drugresistance/publications/WHO_CDS_CSR_
DRS_2001_4/en/index.html
 http://www.scientificamerican.com/article.cfm?id=malariaresistant-mosquitoes-lab-bred-first-time
Group 4: Peppered Moths
Group 4 will look at the evolution of the peppered moth in
industrial UK (industrial melanism, quite controversial!)
 http://www.techapps.net/interactives/pepperMoths.swf
 http://www.christs.cam.ac.uk/darwin200/pages/index.php?p
age_id=g5
 http://www.youtube.com/watch?v=LyRA807djLc

 http://www.bbc.co.uk/radio4/science/thematerialworld_2007
1011.shtml