Exam 4 Flashcards
(73 cards)
Of the four “primary population parameters”, what are the two that increase population density?
natality and immigration
What is the type of interspecific population interaction in which each population is negatively affected by the other population?
interspecific competition
give one of the equations for exponential growth of a population
Nt = NoRo ^t ; Nt = No e^rt ; dN/dt = rN
Give the Pearl - Verhulst Equation for logistic Growth of a population
dN/dt = rN (K-N/K)
Point on the logistic growth curve where the largest number of individuals are being added to a population
1/2 K
Draw the age pyramids typical of (a) growing population, (b) a stable population, and (c) a declining population. For each, give an example of a country showing such an Age pyramid
triangle - growing - India
Upside down U - stable - U.S.
light bulb - declining - germany
In the context of interspecific competition, what are alpha” and “beta”?
The competition coefficients ; effect of species 2 on species 1, and vice versa
According to the competition Equations, what are the four possible outcomes of interspecific competition?
1) species 1 wins
2) species 2 wins
3) Unstable equilibrium - one wins, but unpredictable which
4) stable co-existence
Explain what “Character Displacement” and “Character Release” are, and give an example of each
- Galapagos Finches –> 2 species evolve differently in area of sympatry, compared to similarities of allopatric populations
- Bermuda Cardinal, New Guinea doves, Cocos Island Finch –> A species expands its niche in areas where competitors are absent
What is the predicted outcome for predator and prey populations according to the Lotka - Volterra equations? What famous study by Charles Elton supported that prediction?
- regular cycling with prey cycle ahead of predator cycle
- snow shoes Hares and Lynx in Canada, from Hudson Bay Company fur records
With respect to the study of predators and prey in Newfoundland,
a) what were the major predator and prey species before humans introduced snowshoe hares?
b) What formerly rare predator exploded in numbers after snowshoe hares were introduced?
c) What prey species did that predator switch to when snowshoe hares were reduced in numbers?
a) wolves and caribous
b) lynx
c) caribou calves
Explain the difference between the “individualistic” and “organismic” views of ecological communities. For each, name one ecologist that advocated for it.
- Each species in a community individually responds to environmental conditions –> Gleason
- All species in a community are interdependent like the organs in an individual’s body –> Clements
Explain the difference between a species’ “habitat” and its “niche”
- where a species lives
- a species’ biological role in a community (its “profession”)
What is the concept of “limiting Similarity”? What approximate differences in size did Hutchinson and Diamond find between competing species of water bugs and fruit pigeons, respectively?
coexistence of competitors requires a sufficient amount of non-overlap in their niches
~ 2x increase in wight of waterbugs;
~ 50% increase in size of New Guinea Pigeons
What are the two things taken into account when a species Diversity Index is calculated for an ecological community?
- species Richness
- relative abundances of different species
What was the “master Gradient of Species Diversity” first emphasized by Alfred Russel Wallace?
Increased diversity with lower latitudes
List 5 factors hypothesized to increase species diversity in an area
geological age
ecological age
precipitation
temperature
What is the “Intermediate Disturbance Hypothesis”?
Communities are most diverse if not disturbed too frequently or too infrequently
What is the difference between Primary Succession and Secondary Succession?
1 –> original community development where there is no soil
2 –> recovery of a community after a major disturbance where soil is present
Draw a graph showing the effects of Island size and Isolation in determining equilibrium number of species in an area, according to MacArthur & Wilson’s Island Biogeography Theory. Be sure to label the axes!
look at answer key (#25)
In the debate over designing nature preserves, what does “SLOSS” stand for?
Which is better: “Single large” or “Several Small” Reserves?
In a typical ecosystem, about how much of the productivity goes into the “brown food web” rather than the “green Food web”?
~90%
List the names of the first three trophic levels in a food chain
1 producers –> 1 Consumers –> 2 consumers
Approximate age of the solar system earth
~ 4.6 by
