Biology 5C ~ Lecture 19 ~ Consequences of Evolutionary Processes

The evidence for evolution can be found in:

-Genetics

-Mathematics + computer science

-embryology + morphology

-paleontology

-developmental + organismal biology

-biogeography

-earth + environmental sciences

-geology

Every biological observation we have ever collected corroborates the fact that life on Earth is the result of:

-Descent with modification
-We are all related and share a common ancestor

Artificial selection:

Breeding organisms with specific traits in order to produce offspring with identical traits.

-Selective breeding
-breed individuals with desirable traits

Humans have used artificial selection by:

-Domestication of crops in early farming communities 10,000 years ago
-domestication of animals, like cat and dogs

Dog breeding:

-first species to be domesticated (15,000 ya)
-selectively breed for certain behaviors
-all one species

Dr. Ted Garland's experiment with selectively breeding mice:

-selected for distance, voluntarily run on an exercise wheel
-After 24 generations, the distance mice could run on a wheel increased.

The biological species concept (BSC):

-populations, or groups of populations, within and among which individuals actually or potentially interbreed and outside of which they do not interbreed
-provides a clear research program

The BSC:

-provides a clear research program

-reproductive isolation can be quantified

-many things we classify as separate actually can mate and produce feral offspring

The longest running evolution experiment:

Lenski's E. coli experiment

Lenski's experiments with E.coli

-80,000 generations!
-The bacteria had evolved the ability to eat the citrate added to their flasks to help them ingest iron. (Aerobic citrate utilization)

Mating preference:

Function that links female propensity to mate to the phenotypic distribution of potential mates

Why does mating preference matter for speciation?

-Can separate lineages over time

First example of evolving natural populations (Three-spine stickleback):

-Variation in "gill raker' length
--Different from various lakes and bays

Second example of evolving natural populations ("Ring species):

-variants interbreed with neighbors
-where the ring "meets" the other side---->no longer mate!
-Look at image!

Third example of evolving natural populations (Greenish Warbler):

-all birds belong to a single population that circles itself
-genetic distance increases with geographic distance!
-where the dots don't disperse, the populations do not interbreed (look at the image!)

The evidence for evolution comes from:

millions of observations across many disciplines

Humans use principles of evolution:

to selectively breed crops and domesticate animals

Experimental evolution uses:

laboratory populations to observe evolutionary mechanisms over generations

Speciation:

Two populations, becoming distinct species, has been observed in natural populations