Unit 3 Flashcards

Question

55. What is a resource? Nonrenewable resource? Renewable resource? What is Liebig’s law of the minimum? What is synergism?

Answer 1

Resource- any substance or factor consumed by an organism and supports increased population growth - Consumed - uses resource for its own maintenance - When availability is reduced, growth is reduced Nonrenewable- resources not regenerated - Space is a nonrenewable resource. Once occupied, it is unavailable Renewable- resources regenerated - Animal food and soil nutrients for plants Liebig’s law of the minimum- Law that states that the potential of a resource to limit a pop depends on availability relative to demand - Each pop increases until supply of the limiting resource becomes depleted - Law applies strictly to resources that do not interact to determine pop growth rate, independent influence Synergism- When two or more resources interact to determine the growth rate of a consumer population - When two resources together promote growth more than either individually

Answer 2

Mathematical model- dN/dt=rN[1-(N/K)] Logarithmic altered how- added competition term alpha Ni/Ki - dN1 / dt = r1N1[(K1-N1-alpha12N2) / K1] o Separate equation for each species o In the absence of interspecific competition, you have normal logarithmic growth to carrying capacity competition coefficient- alpha12 is the degree to which sp. 2 uses the resources of species 1 - alpha 21 (beta) is the degree to which species 1 uses the resources of species 2 When would sp. 1 exclude sp. 2- when sp. 1 isocline is higher than sp. 2 when 2 exclude 1- when sp. 2 isocline is higher than sp. 1 when go either way- When the isoclines cross When coexistence- same as could go either way but with stable equilibrium point

Answer 3

Gause’s principle- Complete competitors cannot exist. Two competing species with identical ecological requirements cannot occupy the same area - Assumes: - Genetically unchanged - No immigration of losing species - Environmental conditions remain constant What types of factors- Abiotic conditions, disturbances, predation and herbivory

Answer 4

APPARENT COMPETITION- INTERACTIONS BETWEEN COMPETING SPECIES THAT ARE MEDIATED BY CONSUMERS (GARLIC MUSTARD’S DOMINANCE RESULT OF HERBIVORY) ASYMMETRIC COMPETITION- ONE SPECIES MAY HAVE A NEGATIVE EFFECT ON ANOTHER AND NOT VISA VERSA

Answer 5

MUTUALISMS- INTERACTIONS BETWEEN SPECIES THAT BENEFIT BOTH PARTICIPANTS - CAN FORM TO COEVOLUTION - LICHENS (ALGAE OR CYANOBACTERIA+FUNGUS) OBLIGATE- REQUIRE EACH OTHER TO PERSIST FACULATIVE- INTERACTION IS NOT CRITICAL TO SURVIVE SYMBIOTIC MUTUALISM- CLOSE TIGHT RELATIONSHIP GENERALIST- SPECIES THAT INTERACTS WITH MANY OTHER SPECIES IN A MUTUALISTIC WAY SPECIALIST- A SPECIES THAT INTERACTS WITH ONE OTHER SPECIES (OR FEW CLOSELY RELATED) IN A MUTUALISTIC WAY

Answer 6

Community- a group of populations of two or more species occupying the same area at the same time Main views of communities- o Organismic (holistic) – Clements  community like a superorganism (loss of one organism means loss of community o Individualistic – Gleason  Environment determines where species are found Who were the main voices on each side- Clements and Gleason What studies settled the debate? - Many today take an intermediate view

Answer 7

open community- diffuse boundaries, ranges independent of eachother, uncommon and diffuse coevolution, individualistic organization closed community- holistic organization, distinct boundaries (ecotones), coincidental ranges (coinciding), prominent coevolution ecotones- sharp, distinct boundaries of species where do you find ecotones? - Along an environmental gradient

Answer 8

continuum concept- Along a continuum you have varying abundance of species gradient analysis- looking at abundance of species across some environmental gradient (ex. moisture)

Answer 9

MEASURE HETEROGENEITY- THROUGH SPECIES RICHNESS, DIVERSITY AND EVENNESS DOMINANCE = AREA COVERAGE OF SPECIES (PLANT) OR BIOMASS RELATIVE DOMINANCE- AREA COVERAGE RELATIVE TO OTHER SPECIES RELATIVE DENSITY= TOTAL INDIVIDUALS OUT OF ALL INDIVIDUALS FREQUENCY = FREQUENCY OF ENCOUNTERING SPECIES AT SPECIFIC INTERVAL (SAMPLE PLOT OR POINTS) SPECIES RICHNESS, HOW CALC.- NUMERICAL COUNT OF NUMBER OF SPECIES SPECIES DIVERSITY- NUMBER OF EQUALLY ABUNDANT SPECIES MACARTHER INDICES- D = 1 / SUMP^2 - GIVES NUMBER OF EQUALLY ABUNDANT SPECIES SHANNON-WEINER INDICES- H = -SUMPNATURALLOGP - MORE COMMONLY USED - GIVES MORE WEIGHT TO RARE SPECIES - WITH MANY RARE SPECIES, USE SHANNON-WEINER WHEN WOULD ONE BE PREFERRED- SEE ABOVE EVENNESS OF A COMMUNITY, HOW CALC (J)- DIVIDE THE ACTUAL SPECIES DIVERSITY OF THE COMMUNITY BY THE MAXIMUM POSSIBLE DIVERSITY OF THE COMMUNITY O J = D/DMAX, WHERE DMAX = S

Answer 10

J-shaped pattern- frequency class plotted against number of species. Most species are rare in a community; There are a few dominant species stability- - 1. Resistance to change - 2. resilience – ability to come back after change diversity stability hypothesis- the hypothesis that higher diversity means greater stability David Tilman study- biomass ratio in prairie before and after a drought. Supported the diversity stability hypothesis

Answer 11

How classify communities – Delineation of communities can be difficult unless the transition between adjacent communities is abrupt (ecotone) - Often arbitrary methods to determine community delineation – - Ordination – (see slides) - Cluster analysis – cluster groups by similarity

Answer 12

# define spatial variation – zonation define temporal variation – succession

Answer 13

Succession – change in community structure in time Sere – a successional sequence Seral stage – A stage in a successional sequence Primary – starting from scratch (no soil or seeds) ex glacial recession, lava Secondary – Remnants are still there (soil, seeds) after disturbance. Ex sea grass

Answer 14

What drives succession – - Facilitation - Inhibition - tolerance What are the models proposed – Facilitation – embodies Clement’s view – each stage paves the way for the next. Early colonizers pave the way for future species Inhibition – the presence of one species prevents another from establishing. When inhibition is acting, succession moves forward only through the death and replacement of established individuals. Favors longer-living individuals Tolerance – a species can invade a new habitat and become established independently of the presence of other species. Early stages are dominated by poor competitors that are good toleraters. Null hypothesis – random colonization and random extinction causing turnover and change in species over time

Answer 15

Characteristics of pioneer species – wind dispersed, many small seeds, stuck to animals, long see viability, low root : shoot, rapid growth, small size, low shade tolerance Characteristics of climax species – eaten by animals, large seed size, few seeds, short seed viability, high root : shoot, slow growth, large size, high shade tolerance Clements view – one climax community Gleason view – potentially have alternate “climax” communities

Answer 16

SOME DISTURBANCE STARTS THE PROGRESSION, TRANSITIONS FROM ONE STAGE TO THE NEXT DISTURBANCE OVER A THRESHOLD PRODUCES AN ALTERNATE CLIMATE STATE

Answer 17

SMALL SCALE DISTURBANCES OPEN GAPS THAT ALLOW FOR SECONDARY SUCCESSION. BEST PROMOTES (ANIMAL) SPECIES DIVERSITY