Background: Two related species of plants live on a mountainside. The San Gabriel High Rose lives from the middle of the
Posted: Wed May 18, 2022 2:17 pm
Background: Two related species of plants live on a
mountainside. The San Gabriel High Rose lives from the middle of
the mountain to the very top; opens its flowers from the afternoon
until the evening; has yellow and red flowers; and is pollinated by
both birds and butterflies. The San Gabriel Low Rose lives from the
middle to the bottom of the mountain; opens its flowers from
morning to afternoon; has yellow and red flowers; and is pollinated
by both birds and butterflies. You study a population in the middle
of the mountain where both species overlap, and find that here, the
High Rose has only yellow flowers, opens its flowers in the late
afternoon, and is butterfly-pollinated. In contrast, in this
population, the Low Rose has only red flowers, opens its flowers in
the morning, and is bird-pollinated. You experimentally hand-cross
the two species and plant seeds in the middle of the mountain;
compared to the pure parent species, hybrid plants grow poorly and
have low fitness.
Question: Explain why the two plants evolved differences in the
middle of the mountain that are not seen at the top or bottom of
the mountain. (ANSWER IN FOR SENTENCES)
Sentence 1: Describe the variability that was initially present
in your starting population. [Hint: this is asking what it was like
when the species initially began to overlap with each other.]
Sentence 2: State which individuals had the highest fitness, and
why.
Sentence 3: Explain what evolutionary force(s) acted on the
population, and why and how it acted. [Hint: there may be several
forces acting at the same time; name whatever forces seem
reasonable to explain the change you describe in the following
sentence.]
Sentence 4: Describe how the population evolved. Be as specific
as you can (e.g., say “increased” or “decreased”, rather than just
“changed”.)
mountainside. The San Gabriel High Rose lives from the middle of
the mountain to the very top; opens its flowers from the afternoon
until the evening; has yellow and red flowers; and is pollinated by
both birds and butterflies. The San Gabriel Low Rose lives from the
middle to the bottom of the mountain; opens its flowers from
morning to afternoon; has yellow and red flowers; and is pollinated
by both birds and butterflies. You study a population in the middle
of the mountain where both species overlap, and find that here, the
High Rose has only yellow flowers, opens its flowers in the late
afternoon, and is butterfly-pollinated. In contrast, in this
population, the Low Rose has only red flowers, opens its flowers in
the morning, and is bird-pollinated. You experimentally hand-cross
the two species and plant seeds in the middle of the mountain;
compared to the pure parent species, hybrid plants grow poorly and
have low fitness.
Question: Explain why the two plants evolved differences in the
middle of the mountain that are not seen at the top or bottom of
the mountain. (ANSWER IN FOR SENTENCES)
Sentence 1: Describe the variability that was initially present
in your starting population. [Hint: this is asking what it was like
when the species initially began to overlap with each other.]
Sentence 2: State which individuals had the highest fitness, and
why.
Sentence 3: Explain what evolutionary force(s) acted on the
population, and why and how it acted. [Hint: there may be several
forces acting at the same time; name whatever forces seem
reasonable to explain the change you describe in the following
sentence.]
Sentence 4: Describe how the population evolved. Be as specific
as you can (e.g., say “increased” or “decreased”, rather than just
“changed”.)