CH5: POPULATIONS & COMMUNITIES Flashcards
in order to feed an animal on the next level of the trophic pyramid, you need to have a squared number of the level below it
Rule of Squares
the science of modeling changes in species abundance
Population Biology
what things control populations?
mortality
reproductive rates
resources
competition
disease
accident
all the MEMBERS of a SPECIES within a particular area
(ex: all of the bluefin tuna in the atlantic)
Populations
How do species get to island?
walking
flying
hitchhiking (ex: accidentally on colonial ships)
rafting
ballooning
evolving (flightless birds)
how old is Guam?
how long has it been above water?
44M years
5M years
Since oceanic islands have no historical continental connection, species arrive by:
human activity (introduced)
natural means (indigenous)
evolution (endemic)
true or false
all individuals alive today are a part of a successful line of established ancestors
true
What is the population growth equation?
N = Birth + Immigration - Deaths - Emigration
S shaped population curve that shows growth and applies to all populations
Sigmoid Curve
slow but positive growth at low N (B>D)
Lag Phase
population increases rapidly over short time as N gets larger (B>D)
rapid growth because more people = more babies
Exponential Phase
population reaches the carrying capacity and growth slows down (B=D)
Stationary Phase
how much resources can sustain that population
influenced by predators, disease, limited resources, etc
where growth slows down and stabilizes
Carrying Capacity
the maximum reproductive rate of an organism, given unlimited resources and the ideal environmental conditions (only applies to females)
Biotic Potential
population exceeds K then lowers then exceeds again and lowers…
Boom-and-Bust population
ability for a species to increase its population size if all offspring survive to reproduce in their parents turn
Biotic Potential / Fecundity
the time required for a population to double in number
Doubling Time
the statistical study of populations
Demography
lots of babies but then decline as age go up; more than half of pop is juveniles
babies die young, poor healthcare, often poor countries
bad because more kids than working class
Rapid Growth
pretty consistent growth
stable working class, having some kids, low mortality
good because enough kids to replace working class
Stable Growth
large working class but not a lot of kids
bad because no kids to replace working class so industries can’t be sustained
Declining Growth
all the species populations in a habitat and their interactions
Communities
living together
Symbiosis
