Evolution Exam 2 – Study Guide & Revision Notes
You should understand how scientists use three different approaches to test hypotheses about
adaptation. - correct answer ✔✔1) Experimental Method
- the use of laboratory or controlled field manipulations to investigate evolutionary processes
- Test observations vs. Predictions of alternative evolutionary scenarios (and vs. Null Hypothesis
2) Observational Method
- you observe what test users do and refrain from interacting with them
Sometimes evolutionary hypotheses are difficult to test experimentally
- Evolutionists make predictions that can be tested by observing behaviors/morphologies under
natural conditions
3) Comparative Method
-seek evidence for adaptive evolution by investigating how the characteristics of organisms,
such as their size, shape, life histories, and behaviors, evolve together across species
- Mainly revolves around comparative evolution by distantly related species is evidence for
adaptation
Experimental Method Example - correct answer ✔✔Wing markings and wing-flapping display in
Zonosemata Flies
Flies (Prey) have dark wing bands and distinctive wing-waving behavior; Jumping spiders
(Predator) are striped and wave legs in territorial display
Researchers cut the wings off of flies and attached them to normal house flies and took normal
clear wings on the Zonosemata flies.
Found that Spiders retreated from flies with barred wings that had wing-waving display, all
other flies were attacked.
, Observational Method Example - correct answer ✔✔Giraffe neck example. Simmons and
Scheepers conducted studies to observe whether the giraffes long neck was used to gain an
advantage in foraging. They found that giraffes fed on foliage that was shoulder height or lower
and that their long necks were adapted as a means of defeated other males in a battle over
females. Bull giraffes employ their heads and necks as clubs and occasionally kill each other.
Behavioral Thermoregulation in reptiles. Ectotherms must regulate body temperature with
behavior. Researchers found that gartner snakes have an optimal temperature of functionality
and prefer medium sized rocks that provide their optimum range of temperature conditions.
Comparative Method Example - correct answer ✔✔Convergent Evolution is the process
whereby organisms not closely related (not monophyletic), independently evolve similar traits
as a result of having to adapt to similar environments or ecological niches
Convergent matches in morphology, ecology, and behavior between mammals and marsupials.
You should be able to evaluate whether a trait is adaptive using observational data. - correct
answer ✔✔
You should be able to evaluate whether a trait is adaptive by the experimental method. - correct
answer ✔✔
You should be able to evaluate whether a trait is adaptive by the comparative method. - correct
answer ✔✔
What is exaptation? - correct answer ✔✔Exaptation refers to situations in which traits perform
a certain function now but either arose for some other function or originally had no function at
all.
Feathers, a classic example of exaptation, appear in the fossil record on the flightless ancestors
of modern birds, but later became instrumental to birds' flight
You should understand how scientists use three different approaches to test hypotheses about
adaptation. - correct answer ✔✔1) Experimental Method
- the use of laboratory or controlled field manipulations to investigate evolutionary processes
- Test observations vs. Predictions of alternative evolutionary scenarios (and vs. Null Hypothesis
2) Observational Method
- you observe what test users do and refrain from interacting with them
Sometimes evolutionary hypotheses are difficult to test experimentally
- Evolutionists make predictions that can be tested by observing behaviors/morphologies under
natural conditions
3) Comparative Method
-seek evidence for adaptive evolution by investigating how the characteristics of organisms,
such as their size, shape, life histories, and behaviors, evolve together across species
- Mainly revolves around comparative evolution by distantly related species is evidence for
adaptation
Experimental Method Example - correct answer ✔✔Wing markings and wing-flapping display in
Zonosemata Flies
Flies (Prey) have dark wing bands and distinctive wing-waving behavior; Jumping spiders
(Predator) are striped and wave legs in territorial display
Researchers cut the wings off of flies and attached them to normal house flies and took normal
clear wings on the Zonosemata flies.
Found that Spiders retreated from flies with barred wings that had wing-waving display, all
other flies were attacked.
, Observational Method Example - correct answer ✔✔Giraffe neck example. Simmons and
Scheepers conducted studies to observe whether the giraffes long neck was used to gain an
advantage in foraging. They found that giraffes fed on foliage that was shoulder height or lower
and that their long necks were adapted as a means of defeated other males in a battle over
females. Bull giraffes employ their heads and necks as clubs and occasionally kill each other.
Behavioral Thermoregulation in reptiles. Ectotherms must regulate body temperature with
behavior. Researchers found that gartner snakes have an optimal temperature of functionality
and prefer medium sized rocks that provide their optimum range of temperature conditions.
Comparative Method Example - correct answer ✔✔Convergent Evolution is the process
whereby organisms not closely related (not monophyletic), independently evolve similar traits
as a result of having to adapt to similar environments or ecological niches
Convergent matches in morphology, ecology, and behavior between mammals and marsupials.
You should be able to evaluate whether a trait is adaptive using observational data. - correct
answer ✔✔
You should be able to evaluate whether a trait is adaptive by the experimental method. - correct
answer ✔✔
You should be able to evaluate whether a trait is adaptive by the comparative method. - correct
answer ✔✔
What is exaptation? - correct answer ✔✔Exaptation refers to situations in which traits perform
a certain function now but either arose for some other function or originally had no function at
all.
Feathers, a classic example of exaptation, appear in the fossil record on the flightless ancestors
of modern birds, but later became instrumental to birds' flight
