Populations Flashcards
population
group same species in given envi.
connective stems abovegrounf
connective stems below ground
both form 1 organism
(FACHBEGRIFF)
stolons rhizozomes
Genet vs. Ramet
Genet (individual):
plant produced by sexual reproduction
Ramet (module):
A clone
clonal group
FACHBEGRIFF
group of ramets
corals, sponges, bryotoans, fungi, ect…
modular organisms
distribution of population
spatial area inhabited by species
species limited to small space
FACHBEGRIFF
endemic
wide range of space (pine)
FACHBEGRIFF
ubiquitous
limits of population
geographic barriers (mountains) other species
division of population
subpopulations living in small patches sorrounded by unhabitable habitate
collection of subpopulations
metapopulation
size of population + formula
defined by abundance (# of indiv.)
pop. density x area
forms of distribution (3 + example)
random (independant on position of other individuals (flowers on field))
uniform (result of negative interaction -> minimal distance)
clumped (suitable found in groups (school of fish))
how to determine abundance
complete count only possible if small area otherwise samples and calculation.
the more samples the preciser
mark and recapturate counts of vocalizations
animals tracks
movement of individuals
importance
(FACHBEGRIFF)
DISPERSAL
assures geneflow between organisms
passive dispersal
wind, water, gravity, animals
wind for plants
birds it fruit and shit kernel
trees move up mountain due to climate change
plant dispersal
organism movement (daily & seasonal)
examples
(FACHBEGRIFF)
MIGRATION
whales and birds (season)
bats leave cave and zooplankton that move up and down in water column(daily)
human effect on population migration
FACHBEGRIFF
dispersal by humans
invasive species:
dominate native species (cat in australia & windmill palm (resistant to temperatures) in ticino)
age structure yes or no?
only age structure when overlapping generations
not: seasonal plants yes: humans
age classes(3)
how to find out age and class?
pre-productive
reproductive
post-productive
htfo?
mark young individuals and follow their through time
bones feeather and furr indicate
tree rings
counting growth rings of tree
FACHBEGRIFF
dendrochronology
effects on population size
when more and when less
population growth
+: birth, immigration
-: death, emmigration
of indiv. surviving a given age
survirorship (given as proportion to birth size)
measures of livetime
types of surv.
life expectancy
mortality curve (mortality rate vs. age)
survirorship curve (survivorship rate vs. age)
convex: most mortality at end (mammals)
straight: survival rate constant (reptiles)
concave: mortality highest at birth low in age(fish, pants)
when die out
when deathrate exceeds birthrate
small populations
higher risk of dying out
demographic stochasticity - random variations in birthrate
environmental stochasticity - random environment events
human influence
currently 5000 animals & 7000 plants considered vulnerable
condition to survive (population size)
FACHBEGRIFF
MVP (Minimum viable population): withstand: births and deaths environmental changes genetic drift catastrophic events
determine MVP
bighorn sheep
depends on life story vertrebrates ~1000 species species with high fluctuations ~10000 bighorn sheep study: 50 didnt survive 100 did over same time period
condition to survive (territorium)
(FACHBEGRIFF)
species examples?
measures to support
MDA (minimum dynamic area):
enough resources
home range size: family, indiv., ect….
carnivores need huge (2 mil. m^2)
-> most found in nature reserves
reconnecting landscapes (fuck roads , pipes, ect…)
random variations in birthrate
demographic stochasticity
random variations in environment
environ. stochasticity
intraspecific pop. regulation (human) if everyone had the same
1 letter every 6.5 y
one coffee every 60 days
suffer from hunger 60 d/y
density regulations
3!
(FACHBEGRIFF)
density dependent mortality -> population increase -> mortality increase
density dependent fecundity -> density increase -> fecundity decr. (fruchtbarkeit)
desity independent -> floods, fires, storms
when a ressource is limiting
affects what?
(FACHBEGRIFF)
competition
affects growth, survival, reproduction
when a ressource is limiting in one species
FACHBEGRIFF
intraspecific competition
when all individuals use less when stress
FACHBEGRIFF
scramble competition
- > cows grasing on a field
- > can lead to extinction
when some individuals survive when stress
FACHBEGRIFF
contest competition
-> only succesfull indiv. survive. the rest dies.
but successors can survive and reproduce
indirect interactions competition
FACHBEGRIFF
exploitation competition
one indiv. uses more and reduces amount for the rest (trees)
direct interactions competition
FACHBEGRIFF
interference competition
indiv. use resources to prevent other access ressources
(eagles)
population response to density elevation (notdying)
FACHBEGRIFF
self-thinnig -> trees get smaller to make more room for others
why does a plant occupy a certain space
- > shading for smaller plants
- > rooting system
- > physically cover ground with leaves
