Soil Stuff

What is ecology?

study of relationships between living organisms and their physical environment

autecology

individual organisms of single species in relation to environment

synecology

homogenous/heterogenous groups of organisms in relation to their environment

What are the six important scales in ecology?

genes & traits, individuals, populations, communities, ecosystems, biomes

biogeography

study of geographic distribution of life - biodiversity over space and time

climax vegetation

balanced ecosystem

What is the role of chance regarding island biography?

chance of species reaching larger island greater than small island; higher extinction rates in smaller populations bc of low genetic diversity and vulnerability to stochastic events

stochastic events

random occurrence or process driven by probability

What are some facts about heterogeneity (diversity) in islands?

heterogeneity higher on larger islands, more variation in conditions and resources

What are five theories of island biogeography?

#species on island eventually constant; #species determined by balance of extinctions and immigration; large islands have more species; #species declines with distance to mainland; no difference between real & mainland islands

What is Natura 2000?

network of nature protection areas in EU

Succession

directional change in species populations, community, and ecosystem at a site following a disturbance

What the difference between primary succession and secondary succession?

primary - on new land that was previously occupied; secondary - after disturbances (faster than primary)

seed bank

dormant collection of seeds residing in the soil, leaf litter, or on surface

rhizomes

horizontal underground plant stems that sends out roots from the nodes

plagioclimax

human-induced climax to succession

What are the four theories on succession?

monoclimax, polyclimax, mosaic, cyclical climax

What is the monoclimax theory, and who theorized it?

Clements; all successions lead to a single climax community

What is the polyclimax theory, and who theorized it?

Tansley; a single climax community can lead to multiple climax communities

What is the mosaic theory, and who theorized it?

Whittaker; climax communities are a result of both biotic & abiotic environment

biotic

all living components in an ecosystem

abiotic

non-living components in an ecosystem

pioneer species

first hardy organisms to colonize barren or disturbed land

allelopathy

one organism produces biochemicals (allelochemicals) that affect other organisms growth

What are the five components of the cyclical succession in nature conservation?

health-lands, pioneer stage, culturally-valued landscapes, natural succession, regular reset of succession

What is the cyclical climax theory, and who theorized it?

Aubreville; species become established only in association with other species

plant-soil feedback

plants alter soil properties that influence performance of seedlings

monoculture

cultivation of a single crop

trophic cascade

indirect interactions that control ecosystems

What group of a food web regulates the ecosystem with a bottom-up control?

resources

What group of a food web regulates the ecosystem with top-down control?

predators

What is the ecology of fear?

risk or perception of predators that changes prey behavior and physiology

What is Net Primary Productivity (NPP)?

Gross Primary Productivity - Respiration

What is Liebig’s Law of the Minimum

limiting resource determines maximum growth

fundamental niche

species can exist based on combination of tolerance ranges for all conditions

What is Shelford’s Law of Tolerance

every species has a max, min, and optimum amount of resources for optimal growth

What is exploitative competition?

indirect competition over resource

What is contest competition?

direct conflict between animals

What is Intraspecific Competition, and what are the two kinds?

competition between animals within a species; exploitative & contest

What is Interspecific Competition?

competition between animals of different species

What is the competition coefficient in the Lotka-Volterra competition model?

ratio between competitive effects of both species

What is Gause’s Principle?

species with identical ecological requirements cannot coexist in same environments

What is niche differentiation?

competing species adjust resource use/behavior to minimize competition

niche shifts

replace niche space

niche contractions/expansions

reduce/increase niche breadth

What are the three diversity classifications (related to distance of diversity)?

alpha - local diversity; beta - two habitats or same environmental gradient; gamma - regional diversity

evenness

distribution of # of individuals over # of species compared to when evenness would be maximal

What does the Shaonnon Wiener Index help us find, and what are the individual components of it?

proportions of individuals of a species; s = species #, Ni = # individuals of species i, Ntot = # of individuals of all species

What is the Simpson’s Index?

probability that two individuals at random are same species

What are some reasons for biodiversity of the tropics?

tropics have more solar energy, more rainfall, less seasonal variation, undisturbed during glaciation periods, resource rich

What is the Old, Climatically Buffered, Infertile Landscapes (OBCIL) theory, and who theorized it?

Hopper; ecosystems will reach a stable environment given enough time

What is the Intermediate Disturbance Hypothesis, and who theorized it?

Connell; intermediate disturbance → support both species that require disturbance to propagate and species that persist through disturbance; high disturbance → pioneer species flourish; low disturbance → climax species flourish

What is the Species Energy Theory, and who theorized it?

Wright; large amount of resources relaxes competition

What is the Resource Ratio Theory, and who theorized it?

Tilman; availability of any one resource increases then other resource is likely limiting

What is the Multidimensional Niche Hypothesis, and who theorized it?

Harpole & Tilman; number of added resources remains significant predictor of diversity loss

What is the Biodiversity-Ecosystem Functioning Theory?

productivity is result of species diversity, not the driver of it

What is soil?

a living, natural body comprised of solids, liquids, and gases that occur on land surface

What is the static view of soil?

soil is an object, resulting from various processes that have altered the original bedrock or sediment

What is the dynamic view of soil?

environmental compartment in which input and output of mass and energy determine characteristics

What are some physical soil properties?

density, texture & structure, stability, porosity, hydraulic conductivity

What are some chemical soil properties?

C, N, nutrients, electrical conductivity, cation exchange capacity, carbonates

What are some biological soil properties?

microbial biomass, microbial respiration, microbial community composition, enzymatic activity, earthworms & nematodes

pedogenesis

complex phenomenon leading to soil formation from mineral and organic parent material

What are the three rock types?

igneous, sedimentary, metamorphic

How are igneous rocks formed?

cooling & solidification of magma/lava

How are sedimentary rocks formed?

accumulation and lithification of sediments or organic material

How are metamorphic rocks formed?

igneous or sedimentary rocks are changed by extreme heat/pressure

How do fauna influence soil?

move organic material & minerals around

How are flora influenced by soil?

determines growth; main source of organic material; influence microclimate & hydrology

Explain the transformation of rock via unloading

breaking up when erosion removes pressure on underlying rocks

Explain the transformation of rock via thermal weathering (thermoclasty)

results from variable thermal conductivity of minerals & rocks

Explain the transformation of rock via gelifraction

caused by ice formation → freezing water breaks rocks

Explain the transformation of rock via leaching

removal of solutes by soil water after dissolution

Explain the transformation of rock via hydrolysis

breaking due to reaction with water

Explain the transformation of rock via ocidation/reduction

electron exchanges cause creation of minerals

mottles

irregular arrangement of spots of color in soil

How are materials transferred within a soil?

bioturbation, pedoturbation, eluviation

bioturbation

mixing materials in soil by animals

pedoturbation

mixing materials within soil by alterations of wet and dry periods

eluviation

mixing of materials in soil by transporting within the solution

cheluvation

formation between soluble organic compounds and normally insoluble metal cations enable transport by percolating water

podzolization

acidic water leaches iron, aluminum, organic matter from surface to lower layer

lessivage

transport of clay in suspension (without chemical alteration)

What is the Mechanical Sieve effect?

chemical changes lead to lower solubility or suspension → dependent on size of transported material and pore sizes in deeper parts of soil

What happens during extreme accumulation duricrusts?

solid layers originate from transport and precipitation of weathered material

gleying

seasonal dynamics in soil water saturation cause mottles

What are the possible ways soil can be transformed?

chemical weathering, hydrolysis, hydration, oxidation/reduction

What are the five layers of soil, and name their corresponding letter?

O - organic layer; A - topsoil; E - eluviation layer; B - subsoil; C - parent rock; R - bedrock

What describes the physical quality of soil?

soil porosity, soil water content

What describes the chemical quality of soil?

nutrient content, concentration of heavy metals

What describes the biological quality of soil?

biodiversity, soil organisms, soil microbial biomass

What are the four types of soil degradation, and list an example of each?

physical - erosion; biological - loss of biodiversity; ecological - loss of nutrients; chemical - nutrient imbalance

salinization

presence of high salt concentrations in topsoil

sodication

saturation of soil with sodium

What happens to plants when the soil is salinized?

reduced water uptake, ion toxicity, reduced nutrient uptake

What are the three types of weathering?

physical, chemical, biological

What are the primary crystalline minerals, and how are they formed?

feldspar, micas, quartz; derived from igneous & metamorphic rock

What are the secondary crystalline minerals, and how are they formed?

silicates, hydroxides of aluminum & iron; formed at low temperatures during chemical & biological weathering

What is the tetra:octo ratio of kaolinite?

1:1

What is the tetra:octo ratio of illite?

2:1