CHARLES DARWIN proposed natural selection to explain evolution published On the Origin of Species in 1859

13.1

ACCEPTANCE OF EVOLUTIONARY THEORY (2005)

Adults were asked to respond to the statement: "Human beings, as we know them, developed from earlier species of animals."

The number of Americans who are uncertain about the theory's validity has increased over the past 20 years.

US breakdown: http://www.religioustolerance.org/ev_publi.htm

AMERICAN OPINION ON THE ORIGIN OF LIFE

SOURCES: GALLUP, 2001; NATIONAL GEOGRAPHIC, NOV 2004

45% agreed with the statement:

“God created Human Beings* pretty much in their present form at one time within the last 10,000 years or so”

37% accept theistic evolution -

divine initiative got things started; evolution as the creative means

* What about other organisms?

WHY OBJECT to EVOLUTION?

• Scriptural literalists : Christian, Islamic, ultraorthodox Jew, Krishna

• Political activism influencing education

• Confusion/ ignorance

VARIATION within a population

Yes!

A varied population is a POLYMORPHIC population

Not here

Why are the jaguars varied, but not the bacteria?

BELL CURVE shows the frequency of a variation in a population

Percent of sample 98% 95% 68%

• Genetic variation reflects mutations in the DNA Variation is visible & measureable

Observe & measure phenotypic variation

Observe and measure variation at the gene level

Heterozygotes express some sickling, but have malaria resistance

OVER-REPRODUCTION creates competition

spiders

toad tadpoles

fish roe

ENVIRONMENTAL CHANGE creates competition

REPRODUCTIVE SUCCESS for the ‘most fit’ causes microevolution

Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus, (MRSA) is bacterium that can infect open wounds, blisters and skin lesions. Resistant to most of the drugs traditionally used to fight the bacteria, ���

VARIATIONS may have differential success

P & R Grant’s finch study of The 1970”s.

13.13

FITNESS?

Fit = most offspring

Not literally ‘fit’

AN ALTERNATE HYPOTHESIS:

The Inheritance of Acquired Characteristics

Lamarck Is epigenetics Lamarckism for the 21st century?

P

F1

F2

F3

F4

F5

Quantify microevolution via changes in frequency (allelic, phenotypic, etc)

1.0

0.33/0.33/0.33

0.5/0.5

0.5/0.25/0.25

0.5/0.5

0.4/0.6

Microevolution can lead to macroevolution in time

Speciation results

One ancestor, many descendants

Adaptive radiation

The adaptive radiation of the Galpagos finches