STUDENT RESPONSES TO CLASS EXERCISE 8/31/01: LIST POSSIBLE PROXIMATE AND
ULTIMATE CAUSES FOR THE FOLLOWING BEHAVIOR:
Scenario 1: When a new coalition of male lions joins a pride of females, the males often kill the
young that are with the females.
Proximate:
Scent of other males on the cubs
Females in heat
Overcrowding
Increase in androgens
Food source
Young are not his (how does he know?)
These were given as proximate, but they seem to me to be ultimate:
Establish dominance
Eliminate competition
Territorial behavior
Eliminate weak
Control population for the good of the group (increase food resources)
Ultimate:
Establish their own genes
Bring females into heat
Reduce competition for food
Control population size
Frees females to hunt for pride
Scenario 2: When moths in Costa Rica are startled, they lift their forewings and expose hindwings
that have bright “eye spots”
Proximate:
Predation stimuli caused moths to open wings; being startled
Flight preparation response
Open wings in response to draft/current of air
Reaction to being touched or hit
Distance predator is away affects whether or not moth exposes hindwing
Breeding season—more active?
These were given as proximate, but they seem to me to be ultimate:
Makes moth look bigger
Natural instinct (I'm not sure exactly what this means—WHY is this an instinct?)
Moths that lifted forewings were more reproductively sucessful
Reproductive success
Open wings to camouflage into environment
Scares away predator
Ultimate:
Evolution of eye spot conferred selective advantage.
Imitation of another animal had selective advantage
Eyespot indicates "poison" to predator
Eyespot makes moth seem like a larger organism led to predator leaving moth alone.
Warning signal to other moths
Scenario 3: Humans eat lots of candy and soft drinks.
Proximate:
Hungry
Convenience, abundance in society
Taste; flavor appeals to human taste buds
Social presure in early development drives humans to consume sweets.
Advertisinig
Stress
Price—inexpensive
Curiosity—tryt it for the first time
Stimulates a desired physical reaction in the body
Need caffeine to avoid aches and pains
These were given as proximate, but they seem to me to be ultimate:
Social pressure among peers
Readily available in the environment
These were given as ultimate, but they seem to me to be proximate:
Taste—enjoy the taste
Quick—good for a fast snack
Consume these because they are the most appealiing
Ultimate:
Performance enhancers.
Complex carbohydrates give workers more energy.
Early humans consumed fruits, which contained sugar and other nutrients; later turned to
preprocessed candy.
Culture (tradition)
Genetic flaws, obesity, diabetes, etc.
Impress opposite sex
Sugar results in higher reproductive rates (evidence??)
Sugar keeps brain alive.
Scenario 4: Lemmings are small mouselike rodents that live in the Arctic. At high population
densities, large numbers leave their homes and travel long distances. Some die by drowning at
they attempt to swim across lakes and rivers.
Proximate:
Lack of food
Not enough suitable housing or dens
Resources exhausted
High predation
More disease in large populations, so they could leave because they were affected
When they cross rivers, they have such a large population, they drown each other
Season or temperature change
They migrate to other places to breed and return
Dominant individuals chased subordinates out of territory.
Find mates
These were given as ultimate, but they seem to me to be proximate:
Natural migration pattern in response to temperature, environment
Lemmings who leave have learned to leave to avoid predators (how are learned behaviors
ultimate (evolutionary) causes?)
Ultimate:
Increase species range, leading to speciation
To gain individual's own territory
Inherited bad genes—can't swim
Allows for greater spread of population, greater population growth
An instinctive natural migration (this does not really tell the ultimate reason for the instinct).
Individuals migrating would not be caught by predators, which are attracted to large groups of
lemmings
To avoid predation
To get ore food
Leaving in groups increases the survival rate when preyed upon.
Sodium is required in the diet (? I don't understand this one)
THESE ARE EXPLANATIONS THAT RELY ON GROUP SELECTION. IS IT LIKELY THAT THIS
WOULD EVOLVE, OR WOULD CHEATERS HAVE HIGHER FITNESS??
It is the way they control their populations—when leaving, the weak ones will drown and the
remaining are better breeders.
Group movement allows for greater changes of some succeeding.