Chp. 37 - 40 Flashcards
Plants in general are inefficient in converting light into E.
How much light is absorbed, used, and then converted?
~1-5% is absorbed
Of that ~2% is used by the chlorophyll
Of that ~0.1-1% is converted into food E
What is Gross Primary Production?
Amount of light E converted into chem E by a group of plants over a given period of time.
GPP - (E used in maintenance & reproduction) = Net Primary Production
Net Primary Production is used for growth &/or stored
What is Gross Secondary Production?
2nd TL
GSP - (E used in maintenance & reproduction) = Net Secondary Production
Net Secondary Production is used for growth &/or stored
What does an Ecological Pyramid represent?
Demonstrates changes in #s of indv, biomass, and E as we move from the producers to the consumers TL
How much E is transferred from one TL to another in an Ecological Pyramid?
~10% E is transferred from TL to TL
~90% is lost as heat into the environment
Energy Definition is?
What are the two Laws of Thermo?
What kind of system is Earth?
Energy - The ability to do work
1st Law - E cant be created/destroyed only converted, Total amount of E in the universe is constant
2nd Law - The Entropy of the universe always increases for every transfer/transformation
Earth is an open system
Why are food chains relatively short?
2 Hypothesises
Energetic Hypothesis - Length of the food chain is limited by the inefficiency of E transfers along the chain
Dynamic stability Hypothesis:
- Long food chains are not as stable as short ones
- Pop fluctuations from environmental disturbances at lower TL are amplified at higher TL
- Longer the FC the harder for top predators to recover from disturbances
- the more unstable the environment the shorter the FC
What is a Food Web
Food Web - 2+ TL provide E for 2+ other TL
What is the definition of Population Ecology?
What are the three parts of Pop Ecology?
Population Ecology - branch of Ecology that studies the activities of populations
Density, Movement, & Population growth & #s
What are the three types of Population Density Distributions?
Random - chance
Clustered - school, herd, flock
Uniform - regularly, territories
What are the three types of movement?
Their definitions?
Emigration - Indv leaves a pop/habitat, We know where it is going
Immigration - Indv enters a pop/habitat, We know where it came from
Migration - Indv leaves a pop/habitat & returns to that pop/habitat
Population Growth & #s:
What is the Biotic Potential?
What is Environmental Resistance?
Biotic Potential (rmax) - the max rate at which a pop increases that results when all the females breed as often as possible & all indv survive beyond reproduction age under ideal conditions
Environmental Resistance - Sum of all environmental factors that collectively inhibit the growth of a pop’s #s
What is the equation for Environmental Resistance?
What do the variables represent?
What does the value mean?
ER = (K-N)/K
K: carrying capacity
N: Number of indv in pop
Meaning - a rate of increase.
- The larger the # the more indv can be added to the pop
What is Carrying Capacity?
Carrying Capacity - The average # of indv in a species pop that can be supported by a particular environment
Describe the ways to measure/estimate a pop density.
2 Ways
Direct count - Count all the indv in the habitat as long as there are defined boundaries
Estimate pop density
- Count indv in boundaries/areas
- Indirect indicators - # of burrows, nests, etc.
- Mark & Recapture
- N = (AB)/C
N: Estimated pop #
A: # first collected and marked
B: # indv caught second time (marked & unmarked)
C: # of marked indv recaptured
What are the two factors of Environmental Resistance?
Describe each.
Density Independent Factors
- Abiotic
- Often catastrophic
- Extrinsic - Not dependent on pop size
Density Dependent Factors
- Biotic - Predation, competition, disease, herbivory
- Maybe catastrophic
- Intrinsic
- Opperates w/in orgs - genes/hormones
What is the equation for how a pop grows under ideal conditions?
r (rate of growth) = (B+I) - (D+E)
B: Births
I: Immigrants
D: Deaths
E: Emigrants
What is Exponential Population Growth?
EPG - population increase in #s under ideal conditions at a geometric rate
What are the two other approaches to life history groups?
Describe them.
Semelparity
- "One-Shot" Pattern - pattern of Big Bang reproduction; Produce large # of offspring - Favored when survival rates are low
Iteroparity
- The opposite
Demography Definition?
What are the 3 rates?
Demography - Factors that determine that size & structure of a pop through time
Natality rate
Mortality rate
Survivorship rate
Describe the 3 Demography rates.
Natality rate - increase in #s due only to normal rate of reproduction over time
Mortality rate - % of population dying over time
Survivorship rate - % of population still alive at verious times after birth
- Three types:
- Type 1: Survivorship is high throughout most of life span until a certain age then drastically decreases
- Type 2: Probability of surviving is similar throughout most of the lifespan
- Type 3: Survivorship is low @ beginning of lifespan & then "evens out" after a certain structure/ change occurs
What is a Metapopulation?
Metapopulation - Composed of 2+ pops of species that are “linked”
- Pops occupy discrete patches of suitable habitat, some patches are not occupied - Patches vary in size, quality, & isolation from other patches - Emigration & immigration are important - Species persist in balance due to local extinctions & recolonizations
Define Community.
How can you characterize communities?
Community - all the indv of all species in a given area & time
- Vegetation and Animals
- Trophic structure
- Species abundance
Species Richness
Diversity - Stability
- Comparing communities
Describe characterizing a community by its Vegetation and Animals.
Type, most common, stratified
Complex vegetation provides diverse habitats for other orgs to occupy and eat
Dominant species
- Most abundant
- Exert "control" over occurrence & distribution of other species
- Keystone species (predators)
- Control community structure not numerically, but by pivotal ecological roles or niches they occupy
What are the two hypotheses about Community Diversity?
Intermediate Disturbance Hypothesis
Dynamic Equilibrium Hypothesis - frequency of environmental disturbances are intermediate, this lowers competition allowing poor competitors to remain in comm.
What is the Equilibrium Hypothesis of Island Biogeography?
Balance between rate at which a new species immigrate to an island and the rate at which the species on the island go extinct
Although species # is at equilibrium, species composition is not
What were the results of the scientists who studied the Mangrove islands, FL?
Island size & distance from a source of colonizers were major factors
Distant islands have less species than closer islands to the mainland due to larger rates of immigration
Smaller islands reach equilibrium w/ a smaller # of species faster then larger islands b/c extinction rates are larger on smaller islands
Why do certain species form a community while others don’t?
Individualistic Hypothesis - chance assemblage of species found in same area b/c they have similar abiotic requirements
Interactive Hypothesis - assemblage of closely linked species, locked into association by biotic reactions that cause the comm to function as a unit
How are Communities organized based on relationships between TL?
Bottom-up model - Mineral Nutrients (N) control everything
N»_space;> V»_space;> H»_space;> P
Top-down model - Predators control everything
P»_space;> H»_space;> V»_space;> N
Define Ecological Succession.
What is a relatively stable community called?
Ecological Succession - orderly & progressive replacement of 1 comm by another until a relatively stable comm occupies the area
Relatively stable community is called the climax community
Describe the 2 types of succession.
Primary
- Areas devoid of orgs - Bare rock, cliffs, new islands, new lakes, new sand dunes - No soil initially occurs - Lichens, mosses, grasses are the first orgs - Full exposer to sunlight - Temperature and moisture changes
Secondary
- Areas where orgs have already been - Abandoned farmland, roadside ditches, lawns - Soil already exists - Weeds are the pioneering orgs - Complexity of theses areas controlled by other orgs
What is the climax community?
The last stage of succession.
- Stability of populations
- Complex interconnected E & mineral cycles
- More biomass, More species diversity
What is Herbivory and the two parts of it?
Define Herbivory Satiation?
Herbivory - Process by which heterotrophic animals eat part/all of a plant
Two parts:
- Defoliation - plant destruction - Seed & fruit consumption
Herbivory Satiation - plants produce so many offspring that animals cant eat them all
What is the stability of a community?
The ability to resist changes or the ability to return to original composition after an environmental disterbance
How can you compare Communities?
The Jaccard Coefficient of community similarity
- C/ (s1 + s2 + C) - Goes from 0 - 1 - Closer to 1 the more similar
s1: Species richness in community 1
s2: Species richness in community 2
C: species that occur in both communities
