Ecology - Chapter 11

What given stable conditions, has greater growth capacity?

aquatic and terrestrial environments

How are pops dynamic?

responding to changes in biotic and abiotic factors

How can pops grow in presence of abundant resouces?

geometric or expoential rates

How does a pop growing at max rate grow?

First slowly, then accelerated (maybe geometric or expoential), but cannot continue indefinitely

What happens when gens don’t overlap?

growth can be modified geometrically

How can a continous pop growth in unlimited environment be modeled?

exponentially

What happens as pop size increases?

pop rate increase gets larger

How does an assumption of constant rate per capita increase seem realistic?

Natural pops may grow exponentially for short time periods if abundant resources are present

How can pops grow expoentially in ideal circumstances?

in favorable environmnets at low densities

Where might exponential growth be important?

during establishment in new environmnets, temporary favorable conditions, and recovery during exploitation

What is suggested by a pop rate growing exponentially for decades or more then beginning to slow?

pop was reaching enviro limits

What is environmental limitations incorporated into?

model of logistic growth

What happens to pop growth as resources are depleted?

slows and eventually stops

Why does pop growth slow and eventually stop when resources are depleted?

exponential growth cannot continue, causing growth rate to slow and pop size to level off

What does the growth rate slowing and pop size leveling off represent?

sigmoidal pop growth curve

What happens in a sigmoidal pop growth curve?

death rate = life rate

What is carrying capacity (k)?

pop size that particular environment can support

What can a finite amount of resources support?

finite # of individuals

How does the enviro influence pop growth?

affecting birth and death rates

What are density-dependent factors?

affected by pop density, biotic factors, disease, competition, and predation

What are density-independent factors?

not affected by pop density, abiotic factors, floods, and extreme temps

What are the most sig environmental problems be traced to?

human pop

What are aspects of human pop that should be known?

history, pop growth, and current state

What are humans?

virtually everywhere and highly clumped at large scales

What is human pop density at small scales?

more variable

What does stable pop look like?

Birth = death

What does declining pop look like?

birth lower than death

What does growing pop look like?

birth higher than death

What do many developed nations have?

stable or declining pops