Studied by 9 peopleAPES 2024
Generalist
large range of tolerance, broader niche (role) and food requirements
Generalists are less
prone to extinction
Generalists are more
likely to be invasive
When do generalists have an advantage
in changing conditions
Specialist
smaller range of tolerance, specific food requirements
Specialists are more
prone to extinction
Specialists have less
of an ability to adapt
Specialists have a
narrow ecological niche
Specialists have an advantage when
conditions are constant
Population growth rate (r) (intrinsic growth rate)
number of offspring an individual can produce in a given time period minus the deaths of individual or offspring during that same time period
Biotic potential
Every population has a maximum potential for growth when there is unlimited resources
K-selected species
low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity
K-selected species tend to be
large, have few offspring per reproduction event, live in stable environments, expend significant energy for each offspring, mature after many years of extended youth and parental care, have long life spans/life expectancy, reproduce more than once in their lifetime
Competition for k-selected species is usually
high
R-selected species
high intrinsic growth rate, which often leads to population overshoots and die-offs
R-selected species tend to
Have many offspring and go over carrying capacity then dieback, be small, have many offspring, expend or invest minimal energy for each offspring, mature early, have short life spans, and may reproduce only once in their lifetime
Competition among r-selected species is
relatively low
K-selected species are typically more adversely affected by invasive species than
r-selected species which are minimally affected by invasive species
Most invasive species are
r-selected
Survivorship curve
A graph that represents the distinct patterns of species survival by cohort
Cohort
a group of individuals of the same age – in a population from birth to the maximum age reached by any one cohort member
How many survivorship curves are there
3
Type I survivorship curve
high survival throughout most of the life span, but then individuals start to die in large numbers as they approach old age
Type II survivorship curve
a relatively constant decline in survivorship throughout most of the life span
Type III survivorship curve
low survivorship early in life with few individuals reaching adulthood
K-selected species tend to exhibit
type I curves
r-selected species tend to exhibit
type III curves
Type I examples
elephants, whales, humans (usually K selected)
Type II examples
chipmunks, squirrels (r selected) raptors and birds of prey (K selected)
Type III examples
mosquitos, dandelions, many fish and frog species (r selected)
Note
Flashcard