Stickleback Post Lab Quiz

1.How did the sticklebacks come to live in lakes?

• At the end of the last ice age, when the water receded the rivers dried up blocking their path to the sea

• They come to the lakes to spawn and discovered it was safer than the ocean

• Humans accidentally deposited the fish in the new location as an invasive species

• Sticklebacks have always lived in both lakes and the ocean.

Genetically, what is the difference between sticklebacks with pelvic spines and without?

• Fish with the spines have the Pitx 1 gene and fish without the spines do not.

• Fish with the spines are not genetically different than fish without spines.

• Fish without the spines have the Pitx 1 gene like those with the spines, but it’s partially “turned off.”

• Scientists have not yet determined what the genetic differences are between fish with and without spines.

What can be learned from the fossils of sticklebacks that cannot be learned by studying live specimens?

• How sticklebacks in different lakes had evolved differently

• How the Pitx 1 gene affects sticklebacks differently than other organisms

• How stickleback fish changed over thousands of generations

• What caused sticklebacks to lose their pelvic spines

What is a model organism?

• An organism which has not changed a lot over time

• An organism that has been widely studied

• An organism that is difficult to study

• An organism that doesn’t have much to teach scientists

Why is it beneficial to study a larger sample of fish?

• A larger sample will allow scientists to observe more fish

• A larger sample takes more time to study

• A larger sample may have many individuals that are the same

• A larger sample is more likely to be representative of the entire population

Thinking scientifically, what is the most likely reason that fish in the different lakes evolved differently?

• Fish in the different lakes were different from one another when they arrived there after the last ice age.

• The water temperatures affected how the fish develop as embryos

• Some lakes had more predators, and different traits were naturally selected in each lake

• In some lakes, spines caused fish to swim slower than in other lakes.

The separation of Stickleback fish in Frog Lake and Bear Paw Lake is referred to as

• genetic drift

• natural selection

• reproductive isolation

• survival of the fittest

What conclusion can you draw from this graph in experiment 1?

• The graph indicates that Bear Paw Lake has more fish than Frog Lake.

• The data suggest that fish in Bear Paw Lake are bigger than those in Frog Lake.

• The graph suggests that all fish in Bear Paw Lake lack pelvic spines and all fish in Frog Lake have pelvic spines.

• The data suggest that the fish in Frog Lake vary widely in pelvic structures.

Based on this graph, in which lake do you conclude that the stickleback fish have more large mouth predators?

• Frog Lake

• Bear Paw Lake

Which layer is the oldest?

• Layer 1

• Layer 2

• Layer 3

• Layer 4