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AcTiViTy ANswer This activity modeled the evolution what would have been the tamest
of just one trait that contributes to wolf in the wolf population (Canis
You may want to review the making dogs the species that they lupus) and into the subspecies of
following terms with students:
are; many additional anatomical, increasingly tamer dogs (Canis
gene: A segment of DNA that physiological, and behavioral traits lupus familiaris).
codes for a particular protein. contribute to differentiating a dog In terms of the game, genetically
from a wolf. And while there are
gene pool: All the genes of all the dogs that are bred for aggressive- isolating dogs and wolves means
members in a population. that the cards from the wolves-
ness, the activity addresses the
selective pressure: Any environ- evolution of genetic tameness in evolving-into-dogs decks are never
mixed with the pure-wolf decks. If
mental factor that favors one trait dogs as a species. wolves and dogs were allowed to
over another.
In the card game students played, regularly interbreed, one prediction
mutation: A random change in a higher hand totals represent might be that the dog’s tameness
gene or a group of genes. wolves with genes that contribute would be reduced and the wolf’s
to tame behavior; lower hand tameness would be increased.
species: Any group of organisms, totals indicate fewer genes for In terms of real life, it would mean
the members of which successfully tame behavior. Students were the two groups would be prevented
breed with each other, producing organized into two groups— from breeding (e.g., exchanging
healthy, fertile offspring.
Group A students modeled a wolf genes) with each other.
genetic isolation: What occurs population that continued to have If dogs and wolves had not been
when two groups of one species an intermediate temperament isolated, the small number of
are prevented from breeding with found in a wild wolf population. “tameness” genes that arose in
each other. While this group underwent the population evolving into dogs
random mutations, the selective
inherited trait: An inherited pressures of the wild continued would likely have been lost in the
characteristic—such as hair and to select for the average wolf. much larger wolf gene pool, where
eye color or muscle and bone Group B students modeled a wolf they would be selected against by
structure—that has been passed population that evolved into the wolf’s way of life. This would
on from a previous generation. have made it very unlikely for dogs
dogs. Random mutations allowed
acquired trait: An acquired Group B wolves to evolve past to ever evolve.
characteristic—such as the ability
to ride a bike or do karate—that is
attained throughout life. Acquired sample results
traits are not passed on genetically.
Group A: wild wolf Population Group B: Tamer dog Population
Initial deck average 7.50 Initial deck average 7.50
5th-round average 7.00 5th-round average 10.00
10th-round average 6.20 10th-round average 12.00
20th-round average 6.25 20th-round average 19.45
dOGs ANd mOre dOGs 3 NOVA TeAcher’s Guide
www.pbs.org/nova/dogs/
