week 1 slides - scottsdale community college
TRANSCRIPT
Fundamental Evolutionary
BiologyBio 234
Scottsdale Community College
Dr. John Nagy
Spring 8-week, 2021
Course GoalsWe have 2 primary objectives in this course:
1) Study how evolution and its mechanisms inform our understanding of all fields of biology, including but not limited to medicine, cell and molecular biology, genetics, ecology, behavior, sustainability, and conservation
These analytical tools involve a fair degree of genetics and mathematics
“Nothing in biology makes sense except in the light of evolution”
2) Develop basic analytical tools of evolutionary biology to support advanced study in all fields listed above, among others.
-Theodosius Dobzhansky
Theoretical Foundations of Biology
Genetics
Evolution
Cell Theory
First Reading Assignment
Read “Baloney Detection and the Tools of Science,” available from the following website:
faculty.scottsdalecc.edu/nagy/teaching/bio-345/readings/
How many breed of dog are there?Different breeds of dog:
Different breeds of dog:
How many breed of dog are there?
Different breeds of dog:
How many breed of dog are there?
Different breeds of dog:
How many breed of dog are there?
Different breeds of dog:
How many breed of dog are there?
Different breeds of dog:
How many breed of dog are there?
Different breeds of dog:
How many breed of dog are there?
How many domestic dog breeds are there?
150 recognized by US kennel club; maybe over 400 world
wide
Where did all these breeds come from?
From where did these breeds come?All domestic dogs trace ancestry back wolves, probably from central Asia
From where did these breeds come?All domestic dogs trace ancestry back wolves, probably from central Asia
Artificial selection: Humans breed animals with traits the breeder
wants to keep
Are these two dogs the same species?
Species Concepts
1) Biological Species (Biospecies): Species are groups of organisms that can (1) actually or potentially interbreed
naturally, (2) produce reproductively viable offspring; and (3) are reproductively isolated from all other such groups.
(Adapated from Ernst Mayr.)
2) Morphological Species (Morphospecies): Species are groups of organisms that share common, distinguishing
physical traits that other groups do not possess. These traits could also be genetic (leads to the phylogenetic species
concept).
Natural selection works like artificial selection except Nature is the breeder.
Wolf
Natural selection works like artificial selection except Nature is the breeder.
Coyote
Natural selection works like artificial selection except Nature is the breeder.
Golden jackal
Natural selection works like artificial selection except Nature is the breeder.
African hunting dog
How many wild dog species are there?36 extant by IUCN Canid
Specialist Group
Many more counting
extinct and extant
True or false?
Reason 1: Evolution is not a theory. It is a phenomenon that has been observed directly and indirectly
Reason 2: Darwin didn’t come up with it. Greek philosophers did, and it was believed by many before Darwin
Charles Darwin developed the theory of evolution?
Charles Darwin
False for at least 2 reasons
Darwin proposed natural selection, which is a theory in the scientific sense (not the popular sense)
Key Concepts
Evolution is the change in heritable variation in a population over time; equivalently, it’s a change in
allele frequencies in a population over time
Natural Selection is a mechanism (cause) of evolution. “The preservation of favored races in the struggle for
life.”
What is the difference between evolution and
natural selection?
Charles Darwin A.R. Wallace
Three central questions
1) Why do species change over time?
2) Where do new species come from?
All three questions are resolved by the concept of evolution by natural selection
Microevolution
Speciation
3) Where do different kinds of organisms--e.g. fish, or amphibians or birds--come from?
Macroevolution
Two HIV+ patients treated by AZT monotherapy
What do these data tell us?
Why did this happen?
HIV Life Cycle
Mutation in HIV reverse transcriptase gene makes HIV resistant to AZT
Summary
POINT 1: Mutations in RT are common.
POINT 2: Some mutations make HIV resistant to AZT
Conclusion: Evolution by natural selection is not random
Natural selection generates resistance to monotherapy in HIV
1) HIV over-reproduces: HIV produces enormous numbers of virions (1010 per person per day), the vast majority of which
do not survive.
2) HIV populations in a single individual are highly, genetically variable: HIV RT has only rudimentary
proofreading ability; therefore, it introduces many mutations during viral production
3) Some HIV variants are resistant to chemotherapy: Example above with AZT
Conclusions1) Source of evolutionary innovation is mutation
2) Not all mutations are beneficial; some are detrimental
3) Beneficial mutations become more common in the population; detrimental ones die out
5) No single individual evolved; the population evolves
4) Therefore, evolution is non-random—only beneficial mutations are retained