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