Exponential growth
Explain the 'Malthusian Catastrophe'
Exponential growth of population exceeds resources, point of crisis
Outgrow resources, linear growth
What is r? in relation to dN/dt = Nr
Per capita of growth per population
intrinsic rate of growth (no factors)
Define density dependence and its dynamic :))
provide an example
Population growth affected by population density - some sort of constraint where environment is now a factor
Resource limitation, transmissable disease, predation (high density only)
stress, competition
What do the terms αGS and αSG mean?
What does the isocline represent?
Alpha terms: competition effect/coefficients
αGS - sheep effect on goats
αSG - goats effect on sheep
Isocline: zero growth
What are the four major interactions discussed in a community?
+/- parasite/host, predator/prey
+/+ mutualism
-/- competitors
+/0 commensalism
What is the stable age structure?
Consistent age percentage
A demographic equilibrium where age groups are consistent
What does density independence even mean??
Example?
Population ignores population density and grows exponentially
"boom and bust cycle"
(colonizers again !?)
Maybe deforestation or hunting
Iteroparity vs. Semelparity?
Example?
Itero: Reproduce over and over, resource allocation for survival and reproduction.
ex. mollusks, birds
Semel: No reproduction, until finally mass resource allocation towards egg production, dead
ex. octopus, squid, pacific salmon
Let's identify a pattern for Lotka-Volterra:
Whichever species has an ____ on the ______, they will dominate the other
Isocline on outside will dominate the other species
What is the ultimate job of a keystone species, what happens when this isn't present?
Keystone: Long-term coexistence! mitigating factor so there isn't a possibility for 1 species to invade.
Type 2: Constant survival (linear)
Type 3: High juvenile mortality (concave up)
When the value of 'r' grows under exponential growth, selection would favor these 2 components.
Higher fecundity
Earlier reproduction
How are k-strategists different from the r-strategists environmentally speaking?
Create a list of their characteristics and trade-offs, like a pros and cons list
Harsh conditions
Pros: longer lifespan, larger body size, larger babies, resource allocation to survival
cons: lower fecundity (babies are most vulnerable), no short generations, less resource allocation to reproduction
Difference between evolutionary and ecological time scale?
Evolution: 2 species coevolve and adapt to species
Ecological: 1 species dominates and the other is driven to local extinction
Caterpillar eats a honeycomb consistently, the same ones in the local area. After a year, the honeycomb starts to taste a bit bitter and leaves a psychedelic effect on the caterpillar. The caterpillar keeps eating the same food supply and after another while, the effect is no longer and the honeycomb is yummy again, what happened?
Generalists to specialists
co-evolutionary relationship
Draw and explain the big three demographic pyramids (Hint: rapid, slow, negative/zero)
Rapid: Big base, triangle (baby boom)
Slow: Big middle, smaller base, even smaller top (lots of middle-agers)
Zero: No base/very little, small top (no baby, lot of elder)
List all of the possible trade-offs of the r-strategists
shorter lifespan
smaller offspring
smaller adult body size (sexual maturity shorter)
What is the difference between the population growth rate- dN/dt = Nr and logistic term (growth rate)-
K-N/K?
Draw graph
Logistic growth: population expansion decreases as resources become scarce, leveling off when the carrying capacity of the environment is reached (S-shape)- dependence
Population growth: Exponential curve- surpasses the 'K asymptote' and continues to grow - density independence
Comp. exclusion: Competing species will NOT coexist, coexistence needs to occur to coevolve.
Character displacement is a species adapting in response to another factor, not another species, under coevolution species must remain in the same area
If I were a king snake and chose to mimic the pattern red, black, and white stripes to avoid the big predators, what mimic is this?
Batesian
How many individuals are in the fifth year in species B? Please explain why they may have the dominating fitness over A?
Reached reproductive age quicker
Shorter generation time with larger intrinsic growth
Possibly an r-strategist that colonized an area faster (exponential growth - and I'm thinking about weeds... or people🧐)
Decline: dN/dt < 0
Growth: dN/dt > 0
0: dN/dt = 0
What ecological conditions might favor semelparous life to evolve from iteroparity?
low chance of surviving to the next breeding season
reproductive success is uncertain, season dependent? ...
When given these conditions, what would the vector look like and what does it say about goat and sheep populations?
(B)
Goats rule, sheep are now locally extinct
Please illustrate with a flow chart the levels of crypsis and how it can be overcome to achieve aposematicism
yummy & cryptic
toxic & cryptic
Aposematicism has to be abundant at high frequency in population to overcome freq. dependence, use a common pattern