chapter 54: Community ecology Flashcards
what is a biological community
accumulation of populations of various species living close enough for potential
what are interspecific interactions
takes place between specie in a community
what are some types of interspecific interactions
competition, predation, herbivory, parasitism, mutualism, commensalism
what is competition
when different species compete for a resource that limits survival and reproduction
what can strong competition lead to
competitive exclusion
what is competitive exclusion
local elimination of the inferior competitor and can lead to extinction; where animals can’t coexist
what can competing for limited resource cause
evolutionary change
what is ecological niche?
relationship that an organism has with the biotic and abiotic resources that it uses in its environment
what can coexist in a community
similar species if there are one or more significant differences in their niches
what is resource partitioning
differentiation of niches that enables similar species to coexist in a community
what is exploitation
+/- interaction
one species benefits by feeding on the other species
where is exploitation common
in non photosynthesis organisms
what are some exploitative interactions
predation, herbivory, parasitism
what is predation
-+/- interaction
one species the predator kills and eats the other which is the prey
what are some adaptations that predators have
claws, fangs, or poison
what adaptations do prey display
hiding, fleeing, and forming herds or schools (clumps)
- morphological and physiological defense: porcupines and skunks
what is aposematic coloration
Animals with chemical defenses often exhibit
bright warning coloration
what is cryptic coloration
camouflage, makes prey
difficult to see in their
environment
what is batesian mimicry
Harmless individuals that resemble
members of a harmful species are
avoided by predators that have
learned not to eat the harmful ones
what is mullerian mimicry
two or more
unpalatable species resemble each other
how can predators learn to avoid unpalatbale species
they encounter more of
them with a similar appearance
description of herbivory
- +/- interaaction
- herbivore eats plant
- harm but do not kill
- most are invertebrates
what is the most familiar herbivore
large mammals (cattle, sheep, buffalo)
what do plants do to prevent herbivores
produce toxic or distasteful chemicals or
mechanical defenses, such as spines or thorns
what special adaptations do herbivores have
- chemical sensors that enable them to distinguish toxicity or nutritional value of plant
- specialized teeth
description of parasitism
- (+/– interaction
-one organism, the
parasite, derives nourishment from another organism, its
host, which is harmed in the process
what are endoparasites
live within the body of host
ex: ringworm
what are ectoparasites
live on the external surface
example: head lice
what are the types of + interactions
mutalism, commensalism
description of mutualism
- +/+
- benefits both species
- each species depends on each other
description of commensalism
- +/0
- one species is benefited and the other is neither harmed or helped
what can positive interactions influence
structure of ecological communities
what are the fundamental features of community structure
species diversity
and feeding relationships
what is species diversity
-variety of organisms that make up the community which has two components: species richness and relative abundance
what is species richness
number of
different species in the community
what is the relative abundance
proportion each species represents of all individuals in the community
what does species diversity provide
stability from disturbances
characteristics of communities with higher diversity
- produce more biomass
- more stable
- able to withstand and recover from environmental stresses
- more resistant to new species
what is a trophic structure
the feeding relationships between organisms in a community
* key factor that affects community structure and dynamics
what is a food chain
s link trophic levels
from producers to top carnivore
what is a food web
group of food chains linked together
forming complex trophic interactions
what do the arrows in a food web show
who eats whom
what does phytoplanton serve as
food for zooplanktons (copepods and krill)
who eats zooplankton
birds
what is the energetic hypothesis
length is limited by inefficent energy transfer
what is the 10% energy rule
10% of the energy is passed on on each level
what are some limits on food chain length
carnivores tend to be larger at higher trophic levels
- large carnivores can’t obtain enough food from their small prey
why is it good to eat prey
they have fat which gives them energy for travelling hunting, and maintaining an optimal body temp
which species have large impact
-highly abundant and have an essential role
-
what is foundation species(dominant)
species that are most abundant or have a large size
what is the hypothesis about dominant species
- most competitive in taking key resources like space water nutrients and light
what are keystone species
differense between foundation and keystone species
keystone is not that abundant
what is an ecosystem engineers
cause physical changes in
the environment that affect community structure
why are trees considered foundations species and ecosystem engineers
prescense creates habitat for other species
what is biomanipulation
used to restore species
- organisms are controlled by what they eat
- organisms controlled by what eats them
what is the bottom up model
influence from lower to higher trophic levels
top down model
control comes from the trophic level
how can top down control have benefits
improve water quality with high abundance of algae
lake water suffers from what
abundance in algae
what does removing fish do to the water
improves water quality
what is the intermediate disturbance hypothesis
states that
moderate levels of disturbance can foster greater
diversity than either high or low levels of disturbance
what does the flood intensity graph show
intermediate have increased species diversity
high levels of disturbance =
decreased diversity
low levels of disturbance
decreased diversity, dominant species excluded less competitve species
what is ecological succession
sequence of changes in
community composition following a disturbanc
what is primary succession
New species begin colonizing where no soil exists
(lifeless area) in a new volcanic area
– Initial species : prokaryotes and protists (e.g.,
mosses
what is secondary siccession
Occurs where soil still exists
– Recolonized of an area after a major disturbance
removed most but not all of the organisms
– Agricultural fields that have been abandoned
