ECOLOGY Exam 1

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Ecosystem: The biotic community & its abiotic enviro functioning as a system

{2 components=
1)living--biotic
2)physical--abiotic}
Earth's Interception of Solar Radiation: Earth intercepts solar energy in *shortway radiation* (from hot masses=sun).
energy passes through atmosphere, then hits surface and is emitted back as *longwave radiation* (from cooler masses=earth).
Longer wavelengths can't pass through atmosphere as easily so some is returned to Earth.
==The Greenhouse Effect==
...crucial to maintaining surface temp of earth...
Temp Gradiant from Equator to Poles: the amount of solar radiation intercepted decreased with latitude away from equator.
*due to earth's tilt*
at higher latitudes radiation hits surface at steeper angle and has to travel through a deeper layer of air

&Reason for the Seasons = Earth's Tilt
(causes parts of earth to receive seasonal differences in solar radiation)
Adiabatic Cooling: Decrease in air temperature through expansion---not heat loss

*responsible for decrease in temp w/altitude*
*ALSO moist air cools slower than dry air
Atmospheric Circulation: air=constant state of movement
due to vertical movements of air patterns & earth's rotation

air/H20 currents deflected rt in N Hemisphere
&
currents deflected lft in S Hemisphere

*3 Cells in each hemisphere
Vertical movements of air (imaginary non-rotating earth): -Equatorial region receives most solar radiation
-warm air rises bc its less dense than cooler air
-warm air from equator rises
=low pressure at surface
=air rising beneath it forces air mass to spread N & S
=as move toward poles air cools & sinks
==raises surface pressure
====that heavier air then moves back toward equator
Patterns in Ocean Currents: caused by
1)global pattern of wind
2)Coriolis Effet

*act like wind until hit continents

(Gyres go west (due2wind) til hit continents then split to N & S then cool, move east(due2wind), hit continents, then flow back to equator)
Gyres: the 2 circular water motions that dominate each ocean

-N Hemisphere = clockwise
-S Hemisphere = counter clockwise
Saturation Vapor Pressure: Max amt of moisture the air can hold at a given temp
Precipitation patterns determined by: Wind,
Temp,
Ocean Currents
Latent Heat: Amount of energy released or absorbed during change in state (of matter)

-more ordered (liquid) to less ordered (gas) state =energy is absorbed

-less ordered to more ordered =energy is released
Evaporation v Condensation: Evaporation= liquid to gas state

Condensation= water vapor to liquid state
Rate of Evaporation = Rate of Condensation Means:: The air is saturated

(when air & liquid h20 meet = molecules freely exchanged)
Pattern: Non-random Spatial Distribution

*due to limits in distribution of organisms (no limits = no patterns)
Population: group of individuals of the same species in an area--Interbreeding
Community: all populations of different species living and interacting within an ecosystem
Ecosystem (in community terms): Communities + Physical Enviro = Ecosystems
*exchanges of materials & flow of energy
(abiotic + biotic)

-adjacent ecosystems interact
Landscape: a "Patchwork" pattern of adjacent ecosystems

(ecosystems linked by H20 flow & movement of organisms)
Basic Unit of Ecology?: The INDIVIDUAL

-responds to enviro
-B & D = pop dynamics
-interactions = communities
-passes genes to next generations = nat. sel.
Why are there limits to distribution?: bc limits to information, genectic know-how

(Life Organized with Information)
Autecology: Ecology of Single Species Population

(like studying certain aspects of gerbils)

("species one at a time")
*population ecology, psysiological ecology, life histories*
Synecology: Ecology of plural species considered together

*wildlife ecology, communtiy ecology, landscape ecology, life zone ecology..*
Population Distribution described by 2 basic laws:: 1) Lieberg's Law of the Minimum
-how much will a bucket hold?
2)Shelford's Law of Tolerance
-thought lieberg's was too simple--you can have too much of a good thing.
(middle--optimum is better than min and max)
Shelford's laws of distribution (law of tolerance): 1)the range of a species is limited by changes in limiting factors (factors beyond limit tolerated by the species)
2)the distribution area (where species can live) is determined by the power of migration & their tolerance

**they live there bc they can stand it & they can get there
Gradiant Analysis: plot of
Species Distribution against a Spatial Vaiable
(elevation, temp, moisture, nutrients)

AKA: relative abundance of individuals of a species along enviro gradiants

---QUANTIFIED LIMITS---
**WHITTAKER**

{shows communities are generalizations...not absolute}
Zonation v Succesion: Zonation=spatial
-changes in community structure across landscape

Succesion=Temporal(time)
-changes in community structure through time
Primary Succession: on Newly Exposed Surface (NO SOIL)

ex. st helens, glacier bay
Secondary Succession: vegetation has been removed but SOIL REMAINS
(after disturbances)

ex. post fire
Changes over succession?: Species presence & Relative abundance
150 year study of succesion?: identify differences in space
which represent
differences in time

(old field succession- when was the field abandoned?)
Trends in Ecological Succesion (from Early to Late): -food webs->more complex
-biodiversity->increases
-specialization->narrows
-nutrient cycling->tighter
-stability->higher
-photosynthetic/respiration (P/R Ratio)->lowers from >1 to ~1
Ecological Succesion definition: change in composition of biotic community over "ecological time" (10-1000 yrs)

ex. abandoned field= weeds->herbs->shrubs
*can be cyclical (fire-prone ecosystems)
Community Evolution: development of regional biota over "evolutionary time" (1000-1000000 yrs)

ex. savannas replaced by grassland as rockies rise & rainshadow forms
Physiological time v Ecological time v Evolutionary time: SHORTEST TO LONGEST:
physiological
ecological
evolutionary
Why does ecological Succession occur? 2 competing (prob both right) theories: 1)FACILITATION MODEL
-early species (pioneers) change the conditions of a site to make it more habitable for later invading species

2)INHIBITION MODEL
-early species resist invasion & remain until they're replaced by:
Competition, Predation, Disturbance
FACILITATION MODEL theory of ecological succession: early species (pioneers) change the conditions of a site to make it more habitable for later invading species
INHIBITION MODEL theory of ecological succession: early species resist invasion & remain until they're replaced by:
Competition, Predation, Disturbance
Natural Selection Requires (2): 1)Variation among individuals
2)differences in survival and reproduction (fitness)
Fitness: contribution individual makes to future generations
Directional Stabilizing Disruptive SELECTION: DIRECTIONAL:
trait shifted to one extreme or the other

DISRUPTIVE:
Favors both extremes simultaniously

STABILIZING:
favors individuals near mean population
MENDEL: 1)alternate units control heritable traits
2)for each characteristic organism has 2 units
3)when 2 units are different the dominant is expressed & recessive is not

(unit = gene/allele)-later
DNA's contained in: Chromosomes
(which are oganized into subunits--GENES)
alternate forms of genes =: alleles
water cycle: solar radiation provides energy for evaporation of water

1-Precipitation
2-interception (some water doesn't infiltrate into ground and evaporates back into air
3-filtration (leads to groundwater)
4-Evapotranspiration (sum of evaporating water from surface and from transpiration {the evaporation of water from leaves/plants}
Water's physical Properties: 1)polar
*H+ O- bonding*
CAUSES
a)hydrogen bonding
b)high specific heat
c)cohesion & surface tension
d)buoyancy
e)high solubility
Specific Heat of Water: large quantities of heat energy required to change state of matter

bc of lattice arrangement of H & O water becomes denser til 4* C then decreases in density

*Ice floats bc lattice structure has holes=not dense
-insulates water below
Cohesion & Surface Tension: Cohesion:
water molecules stick to eachother resisting breaking

Surface Tension-
water hits air=weaker attraction than water to water below
Viscosity of water: due to cohesion (attraction of water molecules = harder to seperate)

viscosity of water is much greater than air
-also due to fact that its more dense than air
----causes buoyancy
Buoyancy: caused by viscosity

if body's weight in water is is less than water it displaces = upward force = buoyancy
*since most aquatic animals have nuetral buoyancy they don't require structural material (skeletons) to hold themselves erect in water

*ps. higher density of water means greater changes in pressure than in air
Water as a Solvent: boundery between air and H20 experiences DIFFUSION (molecules move from high concentration to low concentration)

= net transfer of Oxygen &Carbon Dioxide
Solubility in water depends on: 1)temperature
-solubility decreases at temperature increases (solubility greater at lower temps)
2)pressure
(solubility increases as pressure increases)
3)salinity
(solubility decreases as salinity increases)

*greater density and viscocity of water limit diffusion from air
Solubility of O2 and CO2 (carbon dioxide): -solubility of O2= low
-solubility of CO2= high
-CO2 reacts w/H20 and produces carbonic acid
--->result in more H+
--->more acidity (more H+ = more acidic)

*alkaline = more OH- less H+
Light & Water: lower angle light hits = more reflected

light in water reduced by:
-reflection
-particles
-water itself absorbs light
Water & Temperature: *high heat capacity *resists change in temp
*high heat of vaporization
*high heat of fusion (energy taken out to freeze

-surface temperatures = reflect incoming/outgoing radiation
-decline in solar radiation w/depth
-most rapid decline = thermocline

*thermocline seperates warm upper "epilimnion" and deeper colder denser "hypolimnion"
--->ESTABLISHING PATTERNS OF ZONATION
Standing bodies of water Circulation in spring/fall: temp & sunlight low
-surface water cools
-becomes denser & sinks
-warmer water goes to surface
-it cools and sinks
=vertical circulation

ps. in winter warmest part is at bottom
Water as a Solvent (in general) *solution w/H20 as solvent = acqueous solution: -can dissolve more substances than any liquid
-nutrients and waste are dissolved and transported
-solubility due to H-bonding (attract molecules carrying a charge)
--->ex. sodium chloride (Na+) & (Cl-) are more attracted to water molecules than eachother.... so they dissasociate and dissolve
(solubility of sodium chloride =HIGH)

*when concentration reaches solute max excess amts are deposited as sediments
water distribution: Oceans
Ice
Goundwater
Surfacewater
Atmosphere
Biosphere

*highest to lowest*
**Hydrosphere crucial to biosphere but biosphere trivial to hydrosphere
first law of ecology: water flows downhill
--integrates ecosystems (connects landscapes)
Simplest measure of Community Structure = Species Richness: number of species w/i a community
Spatial Patterns: -species distributions/limits
-productivity (primary & secondary)
-Biotic Communities
Time Patterns: -individual position/movement
-population dynamics
-ecological succession
-community development
(community evolution)
Mosaic: patchwork or different types of land
(all in an ecological community)
*product of boundaries defined by changes in structure of distinct patches
Patches: -distinct LOCAL communities
-realatively homogeneous
-differ from surroundings in structure and species comp
-embedded in matrix
-produced by variations in geology(rocks), topography(physical structure), soil, climate, human activity, natural events (fire, grazing)

*crop fields, forests, ponds*
Landscape Ecology: study of causes of formation of patches and boundaries (and the consequences of these spatial patterns--concerned w/size/shape of patches)

[the interactions depend on size and spatial arrangement]

(think of ecosphere as hierarchy)

*landscapes dynamic in space and time (change occurs)
*complexity is key
Matrix: group of many different patches
Patches' area, shape, & orientation determine: -their suitability as habitats
-influence ecological processes (wind flow, seed dispersal, animal movement)
topography: physical structure of a landscape
Edges: the perimeter of a patch
Inherent Edges: -abrupt change in physical conditions (topography, substrate, soil type, microclimate)BETWEEN COMMUNITIES (patches)

-long term natural features (like rock outcrops)
-usually stable & Permanent
Induced Edges: -resulting from natural disturbances (fires storms floods) & human activity (housing, farms)

-edges that are subject to successional changes over time
Borders: where edge of one patch meets edge of another

(area of contact, seperation, transition between patches)
Wide Borders form transition zone called: ECOTONE
Edge Species: species restricted exclusively to edge environments
Edge Effect: high species richness bc they can support species of adjoining communities & opportunistic species adapt to edges

influenced by
-border area available
-greater contrast between patches= greater diversity
Corridors: strips of similar habitat
-connect seperate patches
-usually of human origin
-provide habitat
-can act as filters/barriers
-permit travel ways
Filter effect: gaps in corridors allow some organisms to cross and restrict others
-can spread diseases between patches
(can be roads)
Disturbance: event that disrupts community structure & function
-create patterns & are influenced by patterns

*Intensity= measured by proportion of total pop that disturbance kills
*Scale= the spatial extent of impact relative to size of affected landscape
*Frequency= mean # of disturbances in a time interval
Small Scale Large Scale Severe DISTURBANCES: SMALL SCALE:
-make gaps
-creating patches of different comp. and stage

LARGE SCALE:
-favor opportunistic species
-species like original pop eventually replace early species

SEVERE disturbances:
can replace a community altogether

*too frequent disturbances can eliminate a species
"Shifting Mosaic": the patches of communities that define a landscape is always changing

-landscape is composed of patches each in different stages of development
Landscapes: patchwork mosaics
Biological Molecules Polymers and their monomers: *Carbohydrates-->Glucose
*Fats-->Fatty Acids & Glycerol
*Proteins-->Amino Acids
*Nucleic Acids-->Nucleotides
Dominant Species: species predominating community
-based on # and size of individuals
Keystone SPecies: have influence on community disproportionate to their #s

-removal causes changes in structure and significant loss of diversity
Basal Species: feed on no other species but are fed upon by others
Intermediate species: feed on other species and are also prey of other species
Top Predators: prey on intermediate and basal species
and aren't fed on by other species
Zonation: spatial change in community structure
Guilds: groups of species that exploit a common resource in a similar fashion

(ex. hummingbirds & other nectar feeding birds exploit flowering plants)
Functional Type: group of species based on common response to environment, life history, or role in community
2 views of community: 1)Organismic Concept of Communities
(clements)
-community as unit - each species component of the whole
-whenever a habitat repeats the same species occurs
-species in association have similar distributional limits
-common evolutionary history & similar tolerances

2)Individualistic/Continuum Concept
(gleason)
-relationship among species in a community are a result of their tolerances --NOT strong interactions or common evolutionary history
Ecology v Environmental Management v Environmentalism: ECOLOGY:
science of understanding our surroundings

ENVIRO MANAGEMENT:
how CAN we work the world

ENVIRONMENTALISM:
how SHOULD we work the world (lifestyle choices)
Modes of Evolution (different time scales): Cultural
Organic
Geophysical
Cosmic

Shortest to Longest
Origin of Life Extraterrestrial Hypo: "seeds" from space arrived on meteorites
Origin of Life Chemoautotrophic Hypo: life from the deep
-from deep sea hydrothermal vents
Mechanism of Organic Evolution: Natural Selection
Darwin Observed (3): 1)Variation
2)Overpopulation
(more offspring produced than survive to reproduce)
3)Competition
(struggle for resources in finite enviros)

CONCLUSION: natural selection

(2/3 ecology[overpop & competition], 1/3 genetics [variation])
Darwin didn't understand: -mutation
-mechanisms of genetics
Fundamental Forces of Nature:: 1)Gravitational
2)Weak
3)Electromagnetic*
*fundamental force of life
4)Nuclear

-Weakest to Strongest-
Fragmentation can occur on what scale: any spatial scale
-from roads to continental drift
Biomes: -bigger than states, smaller than continents
-distinguished by vegetation & climate
-emphasize evolutionary convergence & -paralled evolution (dissimilar organisms come to look similar *placental & marsupial animals*

*biomes regional community, life zones local community*
2 types of environmental change (succession): 1)autogenic - result of organisms in community
2) allogenic - of physical enviro (temp)
Riparian Corridors: woodland along bank of river
The most abundant elements in earth's crust are: (3): Oxygen
Silicon
Aluminum
Fathers of Ecology:: Hunters/Gatherers
Leeward side of mountain =: rain shadow
Life zones driven by: *temperature
*precipitation

*soils

(life zones more useful in steep gradiants bc H20 flows downhill)
standing water zoned by :: 1)temperature
2)production/respiration (P/R Ratio)
6 Major Elements in Organic Molecules: H -hydrogen
O -oxygen
C -carbon
N -nitrogen
P -phosphorous
S -sulfur

(CHNOPS)---HOCNPS
Land : H20 =: 1 : 3
Atmospheric Gas Content: 1/4 Oxygen
3/4 Nitrogen
Efficiency of Energy Transfers: 10%

(100- plant =
10- 1* consumer =
1- 2* consumer)

*=degree
Humans are expensive for biosphere to maintain bc: -large
-warm (endothermic)
-consumers (herbivores, carnivores, omnivores)
ecosystem ecology: study of whole living systems
phsiological ecology: responses of individuals to environmental conditions
(temp, moisture, light)
The Grants' (people): documented natural selection (& the different types) on galapagos islands after darwin
Chromosomes Genes Alleles Locus Homozygous Heterozygous Genotype Phenotype Gene Pool: Chromosomes(contain DNA)
Genes(subunit on chrom that carries DNA)
Alleles(alternate forms of a gene)
Locus(where allele occupies chrom)
Homozygous(allels on locus are the same)
Heterozygous(alleles are different)
Genotype(sum of hereditary info)
Phenotype(external expression of genotype)
Gene Pool(total collection of genes in all individuals of a pop)
Hardy-Weinberg Principle: gene frequencies will remain the same over time IF

1)mating is random
2)mutations don't occur
3)pop is large
4)natural selection doesn't occur
5)migrations don't occur
Biological Species: a group of populations whose individuals have the potential to interbreed
isolating mechanisms: allow a species to remain distinct
-reproductive barriers --don't allow exchange of genes between populations

--premating (habitat, isolation, behavior, mechanical)
OR
--postmating (reduce reproductive success of offspring that arise from mating of ind of diff species)
Hybrids: offspring resulting from mating of 2 diff species
Sympatric species: occupy the same area at the same time -- opportunity to interbreed
Allopatric Species: occupy areas seperated by time or space (don't come into physical contact with eachother)
high temps lethal to most organisms bc: they denature proteins
life zones: NOT the same as biomes

*are influenced by temperature
international biological program in the US (US-IBP): efforts organized by biomes
MERRIAM: life zones
conservation ecology & population ecology...: go hand in hand
ODUM: brought engeneering perspective to ecological energetics
science is:: -a search for patterns of cause and effect in the universe

-common sense--natural way of working the human mind

-an evolution tested process
an african plant is similar in appearance to a mexican plant: convergent evolution

(development of similar characteristics of species in different areas but under similar enviro conditions)
organic evolution: *change in gene frequency over time

[central concept in ecology]
based on lecture scientific study of ecology in colorado began with: paleolithic people ~15,000 yrs ago
biological magnification: accumulation of fat-soluble chemicals thru food chain

(pesticides etc)
communication necessarily involves: 1)sending individual (or cell)

2)receiving individual (or cell)

3) irritability (biological sense of word)
larger edge per area advantage of who?: -small!

(in support of several small argument)
people involved in laying foundations for conservation ecology: -macarthur
(mathematical ecologist)

-e.o. wilson
(sociobiologist)

-darwin
(pioneer evolutionist)

-elton
(community ecologist)

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