Test 3 Flashcards
What are Intra-specific interactions?
interactions between individuals of the same species
What are Inter-specific interactions?
interactions between individuals of different species
What are parasitoids?
parasitoids consume the living tissues of the other species, eventually killing them
Are population sizes regulated by what they eat, or by
who eats them?
Both! Their populations are impacted by both bottom-up and top-down control
What is an example of predators limiting prey populations
snakes being introduced to Guam leading to the extinction and decline of many bird species
What is an example of herbivores limiting producer populations?
The cactus worm significantly impacting effected cactus populations
What is biological control?
reducing “pest” populations by intentional introduction of their consumer
What is the story of cane toads?
Cane toads were introduced by colonists of Australia to control native beetles that attack sugar cane crops. However, the toxins the toad excretes kills most predators. It also failed to control the beetle population
What is a trophic cascade?
Effects of predators propagate downward through food chains; the sign of the effect alternates at each lower level between positive and negative
What are the different types of evolutionary defenses?
Behavior, Crypsis (camouflage), Structural (thorns, tougher scales), chemical, and mimicry
What are the 4 Intra-specific interactions?
Cooperation, selfishness, altruism, and spitefulness
Predator-prey cycles are internally-generated by the effects of?
- resource populations on consumer populations
- consumer populations on resource populations
What is the Lotka-Volterra model?
The model of predator-prey interactions that was based on oscillating chemical reactions
What is the prey portion of the Lotka-Volterra model and what does each portion mean?
dN/dt = rN − cNP, the rN portion is the additions with r being the intrinsic growth rate of prey and N being the prey population. the cNP portion is the removals with c being the capture rate and NP being prey pop * predator pop to get the encounter rate
What is the predator portion of the Lotka-Volterra model and what does each portion mean?
dP/dt = acNP − mP, the acNP portion is the additions with cNP being the removal rate for prey and a being the conversion efficiency (<1). The mP portion is the removals with m being the morality rate for predators
When is the prey population increasing and decreasing in the isocline?
The prey isocline increases when the predator population is below the joint equilibrium point (JEP) and decreasing when it is above the JEP
When is the predator population increasing and decreasing in the isocline?
The predator isocline increases when the prey population is above the joint equilibrium point (JEP) and decreasing when it is below the JEP
What is a type 1 functional response?
Predator’s rate of prey consumption increases linearly with prey density until satiation
What is a type 2 functional response?
Predator’s rate of prey consumption increases linearly, but begins to slow as prey density increases (found in species with high handling time)
what is a type 3 functional response?
Predator’s rate of prey consumption is low, then rapid, then slowing under low, moderate, and high prey densities
What is a numerical response?
an increase in predator density through population growth or migration (predators migrating to an area with more prey)
What is an vector?
an organism that parasites use to disperse from one host to a new host
What is horizontal transmission?
When hosts transmit parasites to non-offspring (think covid spreading from person to person)
What is vertical transmission?
When parents transmit parasites to their offspring (literally just STDs)
what does b stand for in the SIR model?
per contact infection rate
what does SIR stand for?
susceptible, infected, and removed
what does g stand for in the SIR model?
removal rate
What does R0 stand for and how is it calculated?
basic reproductive ratio, b/g (infection rate/removal rate), if R0 >1 then infection spreads if R0 <1 then infection dies out
What is Exploitative (“scramble”) competition?
resource is accessible to all competitors, who negatively affect one another by simultaneously driving down the abundance of the shared resource
What is Interference (“contest”) competition?
individuals block their competitor’s access to the resource, taking it all for themselves
What is Liebig’s Law of the Minimum?
Populations will increase until the supply of their most limiting resource prevents it from increasing further
What is the competitive exclusion principle?
Two species cannot coexist indefinitely when they are both limited by the same resource
How do species coexist?
multiple resources, shared consumer, spatial resource variation, and temporal resource variation
What is apparent competition?
when two species have a negative effect on one another via a shared predator, parasite, or herbivore
What is competition-defense trade-off?
when the better competitor suffers more from consumers, and vice versa (the competitor with the biggest population is eaten the most)
What is the difference between a generalist vs. specialist in mutalism?
the diversity of their partners, a generalist has many partners and a specialist has few or one
What is the difference between a obligate vs a facultative in mutualism?
the degree of dependence on mutualist for fitness, an obligate is very dependent and a facultative isn’t dependent
What are the types of mutualism?
Nutritional Exchange, protection, transportation, cooperation by-product
What is an example of a mutualism cheating?
cleaner fish (Elacatinus evelynae) eat parasites off of other fish (+ / +), but switch to eating fish mucus & scales (+ / –) when parasites loads are low
What are some examples of ways species have delt with cheaters?
-plants allocate more carbon to better mycorrhizal fungi
-Yucca moths are specialist pollinators, but also lay their eggs in the developing plant fruits, if the moth lays too many eggs the fruit is cut off from the rest of the plant
What is a community?
all populations of species living together in the same area
What is an Ecotone?
: a sharp boundary in environmental conditions that is accompanied by a major change in the composition of species in the community
What are the theories on community structure?
Interdependent community concept (Clements) and Independent community concept (Gleason)
What is the Interdependent community concept (Clements)
Species occur and interact together because they are highly interdependent, functioning as a superorganism
What is the Independent community concept (Gleason)
Species occur and interact together because they have similar adaptations and habitat requirements
What is species richness?
The number of species in a community (not the number of individuals)
What is the latitudinal diversity gradient?
Tropical biomes tend to have higher species richness than temperate and polar biomes
