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BIOL 103 Study Guide - Final Guide: 1918 Flu Pandemic, Sickle-Cell Disease, Allele Frequency


Department
Biology
Course Code
BIOL 103
Professor
Virginia K Walker
Study Guide
Final

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Biology 103 Weeks 7-12 Evolution and Diversity
Dr. Chippindale
Office Biosci 2420- drop by if door is open
Evolution of Infectious Diseases
Zika:
oZika forest is in Uganda where there was the Rockafeller research centre
ofirst isolated a strain of Zika in 1947
oZika is now spreading rapidly out from a narrow equatorial band
oZIKV is an arbovirus (arthropod borne)
oDengue, yellow fever, chinkangunya and West Nile are all arboviruses
oLinked to microcephaly (small head, less brain capacity), in still born
children whos mothers had Zika they found lost of Zika in their brains,
and Guillian-Barre Syndrome (body attacks nervous system which causes
paralysis)
oMicrocephaly is caused by 8 recessive genes
Causes decreases brain size and function
In inbread populations there are many cases of microcephaly, “rat
people of Lahore Pakistan”
Scientists study these genes to understand how human brains
developed
Phylogeography: relating the strains of viruses to where they originated
Seasonal Flu:
oFlu viruses are characterized as being of type A, B, or C
oType A:
most mutable and epidemiologically dangerous
strains are monitored closely and classified by Haemagglutinin and
Neuramindase proteins
changes in proteins create antigen profiles that are novel to
populations
oAntigenetic drift: surface proteins change, caused by mutation
oAntigenetic shift: surface proteins change, caused by recombination
between strains
oA special concern is recombination of strains native to other animals
with those found in humans
oShifts can cause a major change in the virus conferring to a high degree
of virulence and novelty
oDesigning Vaccines:
Based on evolutionary predictions, which strains are probabilistic
Data on the mutability of key surface antigens (HA, NA) and the
virulence of the bug
2015-2016 Vaccine: H1N1-A strain from California, H3N2-A strain
from Switzerland, Yamagata-B lineage virus

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Evolution of flu strains
Spanish Flu
oH1N1 strain
oCalled Spanish flu because only Spain reported it because they were
neutral, all other countries didn’t want to show they had been
weakened by it
o1918-19: during WWI, soldiers in trenches were easy targets
oKilled 50-100 million people, sometimes within hours of infection
o30% of people worldwide were infected
omortality rate of 15-34 year olds is 20 higher than any other flu epidemic
known, the flu usually kills babies and people 65+
o
oeffect of pandemic flu tends to increase with higher immune response,
body kind of kills itself
opregnant women also at a greater risk
o3-5% of the worlds population died as a result
ocaused eruptive hemroging
odid the 100 days’ war end the war or the Spanish flu? When the war
ended there were the highest mortality rates from H1N1
Bird Flu
oH5N1 (avian flu)
oStrain of influenza virus A (Orthomyxoviridae) negative sense, single-
stranded, RNA virus
oVery limited human-human transmission
oAlso little human resistance and widespread endemic population in
birds in Asia
oBirds can spread the disease globally
oIf it recombined with human virus it would be horrible
H1N1 Swine Flu
oHit in 2 waves
oAlmost like Spanish flu which hit in 3 waves like most flu’s do
oAfter H1N1 there was no flu in the winter… why???

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o
Why study evolution?
oIt helps to explain the world around us:
Who we are, where we came from, where we are going
How to understand and protect biotic diversity
The significance of variation within populations
Engineer new products and tools
Combat disease and pests
Forecasting the future of species
“Nothing in biology makes sense except in the light of
evolution.”- Theodosius Dobzhansky (1900-1975)
oDarwin
Found fossils of extinct megafauna with small living relatives in
cliffs
He studied the decent with modification of mocking birds and
finches
Found a fossil forest at 7000ft- evidence for tectonic movement
Variation between breeding groups, observed variation is
heritable, variation influences fitness (more successful in
survival and reproduction)
Darwin sat on his findings for 20 years, not because he was afraid
the church would excommunicate him but because he was busy.
He published when Alfred Russell Wallace wrote to him and had
the same finding Darwin had. They published their papers
together.
Evidence for Evolution
oEvidence for evolution consists of both historic, experimental, and
contemporary observations:
Evidence in Action: direct observations, disease virulence & drug
resistance, artificial selection & experimental evolution,
adaptation to anthropogenic change & biological invasions
Adaptation: evidence of inherited qualities of phenotype that
enhance fitness
Homologies: related species share many of the same parts but
they are often used in different ways or no longer used
Fossils: organisms have changed dramatically over time
Biogeography: geographic distribution of species provides
evidence of evolutionary change
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