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Go to HHMI lecture: http://media.hhmi.org/hl/05Lect2.html
Lecture 2 Start at section 23 (start at time 29:47 -39:03).
Note: The entire lecture is quite interesting and you have enough background to understand it with no trouble. I didn’t get all that excited about the selective breeding for corn, but the dog selective breeding (and the experiments with different crosses) is well worth watching (the dog selective breeding is in sections 13:00-20:00).
Starting at Section 23
- What was Darwin’s key analogy?
- How did his understanding of artificial selection help inform his ideas about natural selection?
- Dorsal spines give what fish its name?
- Is the stickleback a large or small fish?
- Ancestral sticklebacks are found in what kind of water?
- How are sticklebacks similar to salmon?
- When the ice sheets melted, they left behind sticklebacks who adapted to local conditions. What is one common predator discussed in the video and how is the stickleback able to escape (sometimes) from this predator?
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| Stickleback And Selectionv 2 |
Stickleback fish
small
Ocean about 3 inches long.
They live in ocean are like the salmons. so they migrate into fresh water streams
Trout, insect are the common predators. Their armors are useful.
How do insects capture the sticklebacks? Why is their armor not beneficial in these circumstances?
Describe the ancestral phenotype.
What structures have been lost or modified through subsequent adaptations to different environments?
How many years has it taken for the fish to evolve different phenotypes?
Next, go to Stickleback evolution at http://learn.genetics.utah.edu/content/selection/stickleback/
READ the information on sticklebacks on the page and watch the interactive/explore.
Questions:
According to the infographic, how many generations did it take for the Loberg Lake sticklebacks to evolve from fully-armored to low-armored?
What is a major phenotypic difference between sticklebacks in oceans and sticklebacks in freshwater lakes?
reach out and grab onto things like spines of sticklebacks reel them in and then
They weren’t so red. This fish has a dye called alizarin red which highlights all
Spine; the teeth in the jaws are extensively modified as the fish adapt to diiferent
last 10,000 years or so
13
low-armored forms of sticklebacks evolve in freshwater. Advantageous trait.