Question

A) How have the historic levels of melanin in human populations changed due to
migration? (1 point)
Humans that produced more melanin became more common as populations
migrated toward the equator.
Humans that produced more melanin became more common as populations
migrated away from the equator.
Humans that produced less melanin became more common as populations
migrated toward the equator.
Humans that produced less melanin became more common as populations
migrated away from the equator.

Question 2
A) How would reducing low-growing plants from an area impact a population of
tortoises with two varieties of neck extension ability: short and long distance?
(1 point)
The proportion of tortoises with the ability to extend their necks a long distance
would increase.
The variety of tortoises that could only extend their necks a short distance would go
extinct.
The proportion of tortoises that could only extend their necks a short distance would
increase.
The variety of tortoises with the ability to extend their necks a long distance would
go extinct.

Question 3
A) In an ecosystem, there are two color varieties within a species of toads: brown
and green. Over 50 years, the proportion of the population that is green increases
from 20% to 50%. Which statement is the most likely to explain this change?
(1 point)
A disease caused a decrease in the proportion of brown toads.
The environment changed such that toads that can jump higher into the trees to
survive better.
The environment changed such that green toads can blend into their surroundings
better.
Pollution caused a decrease in the proportion of brown toads.

Question 4
A) In an ecosystem where most flowers are long and bell-shaped, there are two
varieties of hummingbird: birds with short beaks and birds with long beaks. What is
the most likely hummingbird population composition? (1 point)
more long-beaked hummingbirds
only short-beaked hummingbirds
more short-beaked hummingbirds
only long-beaked hummingbirds

Question 5
A) In an ecosystem, the average temperature increases, causing a shorter winter.
There are two varieties of rabbits in this area, white-furred rabbits and brown-furred
rabbits. Which scenario is most likely? (1 point)
The proportion of white-furred rabbits in the population declines.
The proportion of white-furred rabbits in the population increases.
Both white- and brown-furred rabbits decline.
Both white- and brown-furred rabbits increase

Answer 1

Q1: Humans that produced more melanin became more common as populations migrated toward the equator.
- Reason: Higher UV near the equator favors darker skin (more melanin) for protection.

Q2: The proportion of tortoises with the ability to extend their necks a long distance would increase.
- Reason: With fewer low plants, taller-reaching tortoises have better access to food.

Q3: The environment changed such that green toads can blend into their surroundings better.
- Reason: Better camouflage increases survival/reproduction of green toads.

Q4: More long-beaked hummingbirds.
- Reason: Long, bell-shaped flowers favor hummingbirds with long beaks for feeding.

Q5: The proportion of white-furred rabbits in the population declines.
- Reason: Shorter winters mean less snow, reducing the advantage of white camouflage.