Intro to ecology shit Flashcards
Whats exploitation, competition, amensalism, commensalism, and mutualism?
E = +/- C= -/- A= 0/- Comm = 0/- M = +/+
obligate mutualism vs facultative
cannot survive without relationship vs can survive but not as well
What do you need to do before determining organism relationship?
Test benefits for both sides
What is the main focuse of ecology
negative interactions
Preditor/herbivore-mediate coex; what are the conditions
presence of a keystone predator/herbivore that keeps ecosystem and relationships in check
-only if the pred/herb negatively effects the superior sp.
Apparent competition
negative affect between sp though not competing directly over a limiting resc.
(maybe through common pred/herb)
What is the outcome of apparent comp?
the sp that can have a higher P* (equilibrium) with the predator wins
T/F: apparent comp is linked to explotatin comp
FALSE
how to prove it is apparent comp
changes in abundance of one prey leads to reduced/increased of the other prey
Whats intraguild predation?
Basic: common prey but one of the predators is prey as well for the other predator
What is explotation comp? interference?
- indirect competition (eating more food)
- directly fightng over food/females
How can IG prey exist with IG predator?
it is better competitor (lower R*) for the shared resource/common prey
IG pred does not die out because it has two resources (the shared and IG prey)
Why is world green?
because preds keept herbs in check
Exploitative Ecosystem Hypothesis
each trophic leve alternates between comp and predation
Odd number trophic levels usually end up as
green worlds
T/F: Trophic cascades can happen without actually eating prey
True : it can just scare away herbs from the area
T/F: cascades cant occur over ecosystems
FALSE
If direct links between trophic levels are stronger than IG links then…
Regular trophic cascade stuff happening
If the IG is stronger than driect links in the Trophic levels then….
it may act in the opposite direction of regular TL if you remove one. (ex: removal of pred may increase plants, even though herbivores will increase)
Rules fro 4 sp, 3 trophic level system
- keystone pred promotes coexistance
- trophic cascade effect : predation can indirectly increase resource
- apparent comp : predation on a productive consumer can allow existqace of a less productive consumer
difference between food and interactino web
food web only has trophic interactions and describes enery flow and arrows not labled.
Why use foodwebs?
easy to make, communicates lots of info (how sp. depend on one another; can make predicitons)
S =
L =
C =
L/S =
- sp. richness
- trophic links
- connectance (L/S^2)
- link density/ trophic link per sp.
consequences through trophic levels
-dramatic drop in enery level and biomass to top
What can flip trophic pyramids?
if the lower trophic level can support a large number of the level above (1 tree to 20 herbivores)
More productivity will have __ food chains, why?
longer
more energy to be transfered to support more biomass; primary production can determine community structure
How would increase in resource abundance affect IG prey and IG pred?
R* met for IG prey then pred -> increase in pred -> decrease and eventual extinction of IG prey
If increased prod doesnt increase chain length that much it can increase __ and ___
trophic links and sp.
If increasing prod. adds sp. and links, why does food chain not increase as much?
though adding new top pred will increase chain…..
-it may change trophic position of top pred instead; add/remove intmd. preds; increase omni of top pred; no change/decrease in chain will occur.
What controls primary productivity?
Bottom up effect (odd levels)
(land = soil;temp water= nutrient availibility)
Top-down effect (even levels-complex webs)
-trophic cascades
List the 3 sp. that have single-effects on community structure
keystone
ecostystem engineers
dominant sp.
explain keystone sp. comm. structure effect
keystone has a disproporitionate effect on organisms
-removal leads to decrease in diversity
Herbivore keystones - how do they do with keystone predictions
if low or high density of keyst. then less diversity, more diversity at medium density
How does productivity alter keystone effect?
increase resource for prey then increase in kyst. pred overall increase i biomass (higher K)
Removing kyst preds can ____ food webs
simplify
Describe eycosystem engineers
-modify abiotic environment therfore affects things that live there
Describe allogenic and autogenic
Physically change the environment by own actions (worms; beavers)
-change environment through their own structure
Descripe single sp. effect with dominant sp.
exerts stron influence on other sp BECAUSE of high biomass
-removal may or maynot have a large effect