Ecology Flashcards
Population
all individuals of 1 species in area
Population density
number per area
Clumped
most common,
group around resources
social behavior
lack of offspring dispersal
Uniform (or close enough)
territory division
fairly uniform resources
Random
rare
uniform resources
ignore each other
Which of the distribution patterns could result in limiting population size?
uniform?
Population Size Estimates
full count
Quadrats
Transects
Mark-recapture
Mark-recapture based on assumption
percent of recaptured individuals that are marked..same as
the percent of the total population that is marked
mark recapture steps
day 1 capture organisms & mark them
day 2 capture organisms & see what percentage of the organisms are marked
mark recapture calculation
day 2 marked divided by day 2 total
equals day 1 marked over total populatin
positive population growth
birth and immigration
negative population growth
death and emigration
Zero population growth (ZPG) :
deaths = births
Migration :
periodic change w/ seasons
Population growth (dN/dt) =
births – deaths
where
d indicates change
N is the number of individuals, t is time
R=
r = net reproduction per capita per unit time
N=
N = number of individuals in population
population growth rate=
rate = r x N
High r….
have lots of babies fast, few deaths
High N……
large populations grow faster
exponential growth
population grows at a rate proportional to its size
a) r remains constant b) ideal conditions allow max r
Biotic potential
: max r for a population
Logistic Population Growth
Exponential Growth slowed
remains constant wavering a little above and below line, steady
Exponential Growth slowed by
Density dependent limiting factors
predation parasites, disease
limited resources, competition
density independant factors
weather, natural disasters, humans
Carrying capacity =
Max # individuals an area can support indefinitely (D)
Life history patterns:
adaptations that influence survival, reproduction & population size
Reproduction Requires Energy
Amount of available energy affects reproductive rates and success
Seasonal reproduction timed to match resource availability
Reproductive strategies match environment to maximize repro success
r-selected
favor low pop density (d independent)
quick production of many small babies
high biotic potential so called r-selected
K-selected
k=carrying capacity
favor high pop density (d dependent)
good competitors
low biotic potential & high parental care
Unstable/changing environments effect on reproduction
can show more rapid evolution
can select different traits each generation
mature quickly and have lots of babies
r-selected
stable environments affect on reproduction
longer life span slower to mature
produce fewer offspring
more efficient use of E
K-selected
3 categories of individuals
pre-reproductive (base)
- reproductive (center)
- post-reproductive (top)
Fast growth =
wide shape
traingle
Slow growth =
narrow shape, very slow growing triangle
ZPG =
straight at bottom, narrows at top
Negative growth =
bottom & top more narrow than center
Species richness
different species
species richness determined by
abiotic factors food supply evolutionary history species interactions physical disturbances (frequency)
species richness highest in
tropics, high primary productivity
old stable ecosystem
Niche =
role in ecosystem - all activites & interactions
Fundamental niche =
niche it would fill if not limited by competition
Realized niche =
actual role played,
area covered,
food used etc
interspecific interactions
between species
intraspecific interactions
within species, competition, mates, social
obligatory interactions
needed for survival
facultative interactions
helpful but not necessary
Interference Competition =
`
one species blocks access of
another species to some resource
Exploitative Competition =
one species is better at using the resource
so gets more
Competitive Exclusion Theory
2 species that use identical resources (identical niche)…
can not coexist indefinitely
One species will go extinct in that area
Gause
studied Paramecium sp.
showed competitive exclusion
Resource Partitioning =
subdividing resources to allow species to coexist
predation
(+,-) One predator kills and eats
more than one prey organism
parasitoid
(+,-) One parasitoid kills and eats
one host organism.
herbivory
(+,-)herbivore eats plant
Symbiotic Relationships
Organisms live closley together Names end in –ism Parasitism Mutualism Commensalism
parasitism
(+,-) Many parasites feed on
one host organism….try not to kill host
mutualism
(+,+) symbiotic relationship where both benefit
commensalism
(+,0) one organism benefits the other is not affected
Co-evolution predator prey
: joint evolution of 2 species that exert selective pressure on each other
Lynx & Snowshoe hare
also common w/ mutualisms
Adaptations:
inherited genetic traits that improve an organism’s fitness
Adaptations Can help
Help plants avoid being eaten
Help predators capture prey
Help prey avoid predators
Match organisms to their habitat
Cryptic Coloration
Camouflage color
Camouflage shape
Camouflage behavior
Chemical Defense
smell, taste, poison, venom
Aposematic Coloration
Warning color
Red/orange- birds
Black & some bright color (contrast for mammals like dogs)
Mimicry
Organism looks/behaves like a different organism
Batesian Mimicry
A harmless/defenseless mimic
looks like a dangerous model
mullerian mimicry
Two dangerous/bad-tasting organisms mimic each-other
Cleaner Wrasse Mimic
Harmful predator/parasite mimics harmless model
physical defense
Armor/Shell/Spines
Teeth/Claws
Speed/Size
