Proximate versus Ultimate questions

BIO 359 – Behavioral Ecology
• Teacher: Charles Janson (see syllabus)
• TA: Sarah Karpanty
• Text: Animal Behavior (Alcock, 7 th ed.)
• syllabus (handout)
• on WEB at http://life.bio.sunysb.edu/bio359
– syllabus, lecture notes, study questions
Exams and Grading
• Three exams
– Exams 1 and 2 are worth 30%, Final is 40%
– Exams are cumulative but biased to recent stuff
• All exams are mixes of short-answer, short essay, and “multiple-choice”
• “Makeup” exams allowed ONLY with approved medical excuse or prior approval
Overview of the course
• Influences on behavior
– Proximate causes (exam 1)
– Ultimate causes (exam 2, final exam)
• Types of behaviors
– Individual vs. the environment and other species (exam 1, exam 2)
– Individual vs. other members of its own species (final exam)
Tinbergen’s 4 questions
• What are the factors that cause the behavior?
• How does the behavior develop during the individual's lifetime?
• What is the behavior's survival value?
• How did the behavior evolve?
Proximate questions
• ‘How’ or mechanism (neural, development)
• Interesting in their own right
• Sometimes important to understand ultimate questions
• example: color vision in NW monkeys
– only 2 loci code for color-receptive pigments, one is X-linked with 3 alleles (distinct
color sensitivities)
– 2/3 of females get 3 distinct alleles and have ‘normal’ color vision
– all males get only 2 alleles and are ‘color-blind’
– consequences for food choice, foraging height, etc.

Ultimate questions
• ‘Why’ = historical or functional
– historical -- why is the trait this particular way rather than some other way that serves a
similar purpose? Evolutionary history of genes.
– functional -- what purpose does the behavior serve? What problem does it ‘solve’?
– adaptive -- does it increase the fitness of those that use the behavior?
Examples of Proximate and Ultimate questions from real organisms
• Crested Owl. Nearly all owls hunt at night and many can capture prey
in total darkness. Proximate: how do they do it? What neural circuits do
they have to permit such hunting? Is this skill learned from parents or does
it develop by individual practice alone? Ultimate: Does nocturnal hunting
provide more food than daytime hunting? Are the prey species different?
Does the owl make efficient choices about which prey to attack?
• Golden Bamboo Lemur. This species, newly discovered to science
about a decade ago by Dr. Patricia Wright of SUNY-SB, has a remarkable
diet. It feeds primarily on bamboo shoots -- but these contain liberal
amounts of cyanide!! Proximate: what cues does it use to decide which
shoots to eat? How does it know when it has had enough of the potentially
deadly shoots? Ultimate: How did it evolve the ability to eat these shoots?
Why does it eat these rather than less poisonous species of bamboo shoots?
• Golden Toad. This species (sadly, recently extinct: 1988), like many
other toads, gathered from a solitary existence in the forest for a few days
each year to mate in large numbers in a few ponds. Proximate: How did
they know when and where to gather? How do they recognize members of
their own species, especially of the opposite sex? Ultimate: Why gather to
mate during only a few days? Do females choose to mate with males and do
these choices increase the fitness of the females (and if so why?).