do some species live for decades while others only live for a year—or
a week? Why do some organisms breed only once, while others breed
many times? How much effort should parents invest into each reproductive
attempt? It’s our curiosity about our world, and the diversity
of species in it, that drives scientists to study life history theory.
Species clearly use very different strategies: some, like annual
grasses, live fast and die young, while others, like hardwood trees,
live a long time and spread their reproductive effort over many
years. But what about species like agaves or bamboo, which live
a long time, storing up energy, and then reproduce all at once?
What ecological conditions favor the evolution of that type of strategy?
How do factors like survival and resource availability affect which
reproductive strategies are most successful?
study of life history strategies is a big scientific field, so here
we’ll focus on one small part: understanding how food availability
and nest predators affect parental investment in birds. This website
summarizes research at CSU that compares two populations of orange-crowned
warblers (Vermivora celata) that breed on the Channel Islands
off the coast of southern California. The islands in question -
Catalina and Santa Cruz - are in close proximity but differ with
respect to their predator communities and relative levels of insect
abundance. Our research makes use of these natural differences to
ask how predators and food shape the life history strategies of
The assignment associated with this
module will involve some data analysis and will ask you to provide
brief answers to a series of questions. We recommend reading the
'Background' and 'Study System' webpages before you proceed to the
'Assignment' page. Looking through the photos on the 'Fieldwork'
page and watching the 'Nest Videos' will also give you a feel for
how we collected some of the data you will analyze. Finally, you
will find additional sources of information
on the 'Resources' page.
We hope this ecology module will provide
a useful introduction to life history theory, and an interesting
peek into research at CSU!
Please proceed to the Background