BIOS 390 Exam 3 - –Answer Hansen hypothesized that arrowheads ...

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BIOS 390 Exam 3

• evaluate evolutionary hypotheses and predictions (irises)

–Answer Hansen (2012) hypothesized that arrowheads on an iris acted as nectar guides for pollinators

• colored in some of the arrowheads or all of them and left some white (control)
• measured percentage of pollinator visits in which the pollinator preferred controlled or

experimental

• supported the hypothesis
• evolutionary adaptations in oxpeckers and impalas

–Answer Weeks (2000) hypothe- sized that they are mutualistic (eating bugs from impalas)

• one group is exposed to oxpeckers and one isn't
• measured changes in tick load and predicted that without oxpeckers the impalas would

have a higher tick load

• saw no difference in tick load
• tried mixing the groups and still saw no change
• they then measured how many open wounds the impalas have and saw more open wounds on

the impalas with oxpeckers

• refutes hypothesis and it is a parasitic relationship
• evolutionary adaptations in tephritid flies

–Answer Green (1989) had three hypotheses about the flies 1) they don't mimic jumping spiders 2) they mimic jumping spiders to avoid all predators 3) they mimic jumping spiders to avoid only jumping spiders

• control group of tephritid flies and one of house flies
• group of tephritid flies with housefly wings
• group of houseflies with tephritid wings
• group of tephritid with reattached wings (control for operation)
• exposed to either jumping spiders or predators
• when the flies had markings and wings, the jumping spiders backed off 1 / 2

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• concluded that they mimic jumping spiders to only care off jumping spiders
• evolutionary adaptations in C.elegans

–Answer Anderson (2011) wanted to know what temperature C. elegans would move to when placed in warmer water, and noted that they moved to cooler water than the warm temperature

• ectotherms move to their Topt when placed close to their critical temperatures
• evolutionary adaptations in garter snakes

–Answer Huey (1989) studied thermoregu- lation of garter snakes

• noted that they changed their habitat throughout the day (exposed v. under rock)
• they measured what size rock the snakes hung out under and they preferred medium

sized rocks

• they measured the number of rocks at the site and noted that it was nonrandom

• evolutionary adaptations in bat testes

–Answer Hosken hypothesized that as bat roost size increased, so would the testes in that group because the larger the testes the more sperm

• they found that larger testes were correlated with larger roost size by studying roost sizes in

different bat species

• correlation does not mean that they evolved in tandem
• had to identify phylogenetically independent contrasts
• did this by identifying sister species and graphing them, then moving them to the origin and

then removing the origin dot and the line giving four points

• these showed divergence that arose between the pair of sister species sicne they evolved

away from a common ancestor

• these points show correlation that when the sister species evolved larger group size they

evolved larger testes

• evolutionary adaptations in feather lice

–Answer Bush hypothesized that body color evolves in response to selection via pruning

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