Three Evolution Scenarios
Return to Mr. Lazaroff's Biology II Honors
Be sure to refer to the 5 steps of Charles
Darwin's
"Theory of Evolution by Means of Natural Selection"
in your answers (1/3 page per question) . . .
There is variation in every population.
Organisms have more offspring than can survive.
Organisms compete for limited resources.
Organisms pass
traits on to their offspring.
Organisms with the most beneficial traits are
more likely to survive and
reproduce.
- Ladybug beetles are bright red with black spots. Unlike many other species of
beetle that choose to camouflage themselves by being brown or green, Ladybugs purposefully
want to be seen by predators. A bird that eats a ladybug is greeted by an extremely
foul taste in its mouth. Given that an individual ladybug with both a foul taste and
a red color cannot possibly pass on its traits while in the stomach of a bird, how did such a trait evolve?
- A Stink Bugs has a curious habit (instinct) of crouching forward and raisining its
abdomen (rump) in the air in order to spray a noxious odor into the air whenever it is
threatened by a predator. There is another insect that has evolved to copy that
behavior (as its own instinct) when it is similarly threatened. Given that this
copycat beetle (copybeetle?) has no "stink" to accompany its behavior, how and why did that form of mimicry
evolve?
- It is generally accepted that land animals evolved from a common aquatic ancestor.
Cartilagenous fish (sharks) evolved into bony fish. Bony fish, or
particularly the lobe-finned variety (as in the Coelocanth), eventually evolved into
amphibians, which were then followed by reptiles. Reptiles, in turn, evolved in two
directions: birds and mammals. The evolution of land animals clearly was due to a
true advantage in being able to expoloit the resources of the land, or, as in the cases of
amphbians and others, the resources of both land and water. Given the distinct
advantage of the anmphibian there is just one question: why
are there still fish?