Directions: Take out your lab and make observations of the tobacco seeds at your table.

Genes vs. Environment?

Cake analogy…

recipe + ingredients = cake

genes + environment = trait

Is a cake more recipe or more ingredients?

Is the difference between 2 cakes due to differences in the recipe or ingredients?

GENES are influenced by the environment.

Winter Coat Summer Coat

The gene for color that is expressed is determined by the temperature (the environment)

WHY? Why might this trait have developed in some species?

- The genes that allowed the weasel to change color made it successful

- Therefore, those genes were passed on to the next generation

Natural Experiment:

Cross-fostering of galah chicks by pink cockatoos

Which species will the galahs behave like?

Are behaviors results of social environment or genetic input?

Depends on the behavior…

Begging calls galahAlarm calls galah

Contact calls cockatooFlight pattern cockatooFood preference cockatoo

galah pink cockatoo

Determined by GENES alone

•Behavior is determined by environment/upbringing

•Ability to vocalize and ability to fly is determined by genes

Migration routes of blackcap warbler populations:

Question: Is migratory behavior learned or genetically determined?

Test: Check migratory direction of offspring of British birds and German birds reared in the same laboratory conditions.

Results:

Conclusions: There appears to be a genetic difference in migratory behavior.

Another test of the genetic basis hypothesis:

Cross birds from southwestern Germany (brown arrows) to birds from Austria (white arrows).

Offspring (blue arrows) flew in intermediate direction!

THE GENES FOR MIGRATORY DIRECTION APPEAR TO BE INCOMPLETELY DOMINANT!!!

IQ studies in humans

Hypothesis: Differences in IQ scores are caused by differences in genes ONLY

Conclusions: Genes alone DO NOT code for IQ score! Eat your veggies and exercise!

http://www.sciencedaily.com/releases/2003/01/030123072840.htm

“anxiety and aggression” gene?

Are there genes for behaviors?

http://www.sciencedaily.com/releases/2004/05/040526063645.htm

Gene Linked To Alcoholism Alcoholism tends to run in families, suggesting that addiction, at least in part, has an underlying genetic cause. Now, researchers at the University of Illinois at Chicago have discovered a gene linked to alcohol dependency. Laboratory mice deficient in the gene were found to consume excessive amounts of alcohol, preferring ethanol to water and evincing highly anxious behavior in a maze test.

Drunken Fruit Flies Reveal Molecular Pathway Regulating Sensitivity To Alcohol (June 17, 1998) -- Researchers at UC San Francisco have identified a molecular pathway in intoxicated fruit flies that is responsible for regulating the flies' meandering, wobbling

responses to alcohol.

“alocholism” gene?