Ecology after midterm Flashcards
(318 cards)
1
Q
What is exploitation?
A
- an individual increasing their fitness while decreasing fitness of others
- eg; herbivory, predation, manipulation, parasitism, competition
2
Q
What is the general relationship between plant herbivory and productivity?
A
- mostly decreases plants growth and reproduction but in grasses increases productivity (overcompensation)
- eg; snow goose grazing, feces grazing and time of year graphs ; as biomass decreases, productivity increases
3
Q
What are the forms of plant defence?
A
- under strong NS pressures due to intense herbivory - develop chemical and physical defences - herbivores must evolve to overcome those defences
4
Q
Describe the physical plant defense?
A
- thorns and spikes; effective against large,not small
tough tissue deters eating
sticky hairs/trichomes
5
Q
Describe the chemical defences?
A
- plants have many metabolites, often shared
- most smell bad, taste bitter, toxic
- toxins: chemicals that kill, repel, or impair herbivores (alkaloids: bitter and smelly)
- digestive enxymes (tannin eg;) make itahrd to digest
6
Q
What are the 3 forms of chemicals?
A
- alkaloids: if eaten followed by atropin can be lethal to animals
- phenolics: eg; tannin - bitter and toxic - causes rivers to turn brown, found in grape skin (wine flavour)
- terpenoids: in over 25000 plant species - many functions, also for odor - repel herbivores and attract polinators - used inertial medicine
7
Q
What are the two forms of plant defense states?
A
Constitutive (constantly produced regardless of environment) and induced (comes from shift in environment)
8
Q
Do introduced herbivores always negatively impact plants?
A
no!
9
Q
What is one of the best studied relationships for understanding impacts of predation?
A
lynx and hares
- graph represents very obvious relationship in cycles between populations, as one increases the other decreases
10
Q
Name and describe the 2 hypotheses that were proposed to describe the clear relationship between hares and lynx?
A
- the sunspot hypothesis: sunspot cycles increase and decrease light availability and alters plant growth causing variation in hare population size - lynx main predator responds - BUT patterns don’t align - rejected
- Lloyd Kieth: overpopulation theories
- period of high growth followed by
- decimation by predators and disease
- physiological stress at high desnity
- starvation due to reduced food at high density
- alternative hypothesis: predators increase in response to high prey density and eventually reduce prey
11
Q
What are the drivers of population cycles between prey and predators?
A
- cycles through a number of co-occuring mechanisms : food availability, high density impacts, predator regulation eg
12
Q
What is the role of food supply in hares and lynx?
A
- hares live in boreal forests with dense growth of understory shrubs
- have high rates of increase can double each generation during growth phases
- extensively browse buds of shrubs and trees- during winter food shortages during peak densities and chemical defense : plants unusable or reduced quality
13
Q
what are the roles of predators in hare populations?
A
- 50-90% of mortality can be due to predation during high densities
- functional response of lynx capped at half density, but coyotes functional response increases beyond maxed hare values
-lynx and coyotes show large numerical response to highharedensity
14
Q
What is functional response?
A
- increased predator numbers in relation to prey numbers
a function of immigration as more move in and incrasedreproduction as resources are abundant
15
Q
what were the results of the ‘rabbit chow’ experiment?
A
- no predation impacts the least, food some, and both increases abundance greatly
16
Q
What are consumptive and non-consumptive effects?
A
consumptive: predators impact the population directly through capture/consumption
non-consumptive: only fraction of prey is consumed - non consumptive are impacts of predators on prey even when not consuming
ie: morphological response, stress physiology, altered behaviour eg; rabbit stress increases (cortisol) when predators present, also decreased reproduction.
17
Q
What is the major conclusion on the impacts on prey?
A
- prey population are influenced by food availability, consumptive and non-consumptive impacts of predators
18
Q
What is the lot volterra conclusion?
A
- predator impacts prey in a cyclic cycle - predator delayed response to prey which is the driving factor
19
Q
How do prey avoid predators ?
A
- animal display and use of refuges
- display: mimicry, batsman mimicry, mullein mimicry, cryptic coloration, physical defences, predation satiation
20
Q
What is predator satiation? Provide an example
A
- predation satiation seeks to protect individuals simply by sheer numbers available
- example: cicada which arise very 13-17 years and overwhelm the ecosystem; animals gorge, trees get nutrients and growth spurt, no defense mechanism just numbers - can’t eat them all
21
Q
Why is size a refuge?
A
- if large individuals are ignored by predators than large size may offer a form of refuge
- elephants can kill lions, starfish removed and mussels grow big enough to avoid predation when star fish reintroduced
22
Q
Can limiting resources change over time?
A
Yep!
23
Q
What are some of the ecosystem changes associated with succession?
A
-increased biomass, respiration, nutrient retention, primary production
- time may also influence ecosystem through weathering
24
Q
How does succession impact soil depth and layering? Define the horizon layers as well.
A
- soil depth and layering both increase
- A is the top soil: get the nutrients which leach into layer B
B: different colour buildups (dense, high nutrient content, less fertile than A) - As succession continues, A and B increase and organic matter and litter also increase
25
What were some observed changes at glacier bay regarding phosphorus, moisture, bulk density, and organic matter?
- moisture and organic matter increased while bulk density and phosphorus decrease as plants take up more space and resources
26
Why do the Hawaiian islands make an ideal chronosequence? What were the observed relationships? (think C, N, and P)
-islands vary in age across million of years, formed above hot spot over tectonic plate in pacific
- different patterns of nutrient distribution
- Carbon and N peaked after 150,,000 years of soil development, while total phosphorus remained the same but refractory increased and weatheable decreased
- N and P had opposite patterns of change
27
Is vegetation responsible for all nutrient loss?
- accounts for some, but not all: but consider other sources (erosion, runoff, microbial processes)
28
What process can reduce the loss of nutrients caused by disturbance?
- succession
29
Define the model of ecosystem recovery?
- disturbance always induces recovery phases
- disturbance followed by 1) aggradation 2) transition phase 3) steady state phase
30
What are the two mechanisms of succession?
Two historical viewpoints:
1) clements: serial replacement sof speies during succession, each wave facilitates establishment of the next
- climax could maintain itself indefinitely
2) Gleason: Speies distributed independently of each other, individualists approach succession with specific conditions and random events altering outcome
31
What did egler do? what were his conclusions?
- clarified distinctions between Clements and Gleason: proposed alternate ways succession might work
relay floristics: one wave of species replaced by next, very little overlap
initial floristics: different species dominate at different times following disturbance, but great deal of overlap: most always present but change in abundance over time
32
What are the 3 models for mechanisms of succession?
- facilitation:
only species with specific characterics can establish, pioneers may modify environment so it becomes less suitable for them but more suitable for later successional species
- environment less suitable for early species, more suitable for later ones
- tolerance: species unaffected by other colonists, initial stages not limited to a few species- juveniles dominant at climax can establish very early on
- environment less suitable for early species, later successional species are ones able to tolerate, no other can tolerate (climax community)
-inhibition
- environment not suitable for all species, resident species inhabit establishment of any others
- early occupants modify environment to make it less suitable for any other species,
- climax: long living species resent to damage by physical or biological factors
33
What are the mechanisms of primary succession following deglaciation?
- multiple methods of succession may operate during succession in the same system
- horse weed inhibits growth of aster (shading, competition, root chemicals)
- aster facilities growth of the broomsedge
- later on broad leaf trees that are resistant to shade
- climax community shade tolerant trees
34
What is stability? How might it arise?
Stability: biologically uninteresting, lack of disturbance , absence of change
- may also arise from:
- resistance: ability to maintain structure/function in face of disturbance
- resilience: ability to recover from disturbances
35
Does primary succession occur on substrate or soil?
Substrate!
36
What is a guild?
- group of organisms that make their living in similar ways (eg; seed eaters in the desert)
37
What are the ecologist terms ?
- life forms, growth form and functional group (reproduction / consumption)
38
What is relative abundance?
The percentage each species contributes to overall species present
39
What two factors make up diversity?
- species richness and species evenness
40
What is the difference between species abundance and relative abundance?
- species abundance : total number of individuals
- relative abundance: percentage each species contributes to the total number
41
What makes species ruchness susceptible to sample size?
- higher sample size = higher species richness
42
What does dominant mean?
- one or few species substantially more abundant than other species in a community
43
What level of abundance are most species in a community?
Most species are relatively abundant (few dominant few rare)
44
What is the lognormal distribution of species abundance?
- curves typically bell shaped: typically only part of the bell curve visible: more samples = lognormal curve!
45
What is required for ecologists in order to have accurate estimates of abundance?
- must conduct substantial sampling
46
What is a widely used measurement of species diversity? Can it be sued to calculate evenness?
- species richness uses Shannon wiener index
(-) sum of proportion x log e x proportion. (proportion is the number of individuals out of the total number)
- Pileou's evenness : (0-1) J used to calculate evenness, H can not
- J = H' / H max (the highest possible proportion used to find H max)
47
What is the relationship between H value and diversity?
- measured 0.5 - 3.5, higher the number the greater the diversity
48
Why is the Shannon diversity index useful to ecologists?
Useful for ecologists studying rare species and their impact on the environment
49
What is a common method used for comparing patterns of abundance and richness?
- plot relative abundance of each species against rank
- longer = more species
- gradual descent = more evenness
generally more diverse population will have gradual slope
50
What is the relationship between environmental heterogeneity and diversity?
Generally diversity increases with environmental complexity or heterogeneity
- eg; warbler species increase when vegetation increases
51
Describe the relationship between niches of algae and plants ?
- Tilman found:
coexistence depends on the nutrient availability
- different species dominate different parts of the lake depending on nutrient availability
- asterionella takes up phosphate at a faster rate than cyclotella
- in phosphorus limiting areas: asterionella dominates
- in silicate limited areas"cyclotella dominates
coexistence when both nutrients are limiting!
52
What do mathematical models predict about populations densities?
Once they reach equilibrium they will not change
- stability maintained by opposing forces, if disturbance occurs population will get back to equilibrium
- forces equal at every point (reproduction and respiration)
53
Why is disturbance difficult to define?
- it is classified as a departure from average conditions (but environmental variability may be an average condition)
- so we say anything that alters environment, ecosystem functioning and processes, dynamics, etc
54
What are the two main factors of disturbance?
Frequency and disturbance
55
What are the two forms of disturbance factor?
Biotic and abiotic
56
What is the intermediate disturbance hypothesis ?
- species richness is highest in areas of intermediate levels of disturbance
- promotes higer diversity
(disturbance is a prevalent feature that significantly influences community diversity)
- too much wipes out species, not enough allows for dominant competitors to take over
57
Define the impacts of different levels of disturbance
low: competitively dominant species would outcompete all other, predominantly K selected species
high: species continuously driven to extinction, colonsiers return (mainly r selected)
medium: yay!
example: pine savannahs on coastal plains of the us have frequent fires- shade making shrubs removed and can't dominate
58
how does Sousas boulder experiment support the intermediate hypothesis theory?
- large boulders have 1% turnover per month, 1 species modal
- small boulders: have 42% turnover, 2 species
- medium: 9%, 4 species (highest diversity! )
59
What are some other examples of ecosystems that do well under mid disturbance ?
- coral reefs: hurricanes , diverse
- boreal forests with a lot of forests :
- bomb army sites have get diversity
60
How do prairie dogs encourage diversity?
- by burrowing they leave dirt in piles, in grasslands : a very common source of disturbance is burrowers
- dogs burrow and remove and eat vegetation : open for plant colonization
- intermediate allows persistence of species that are good colonizers and species that are good competitors
--> grass diversity increases, shrubs diversity invariant
61
Why might different groups of species respond differently to different levels of disturbance?
- different life history and niches
62
is the intermediate disturbance hypothesis true?
- less than 20% of studies expressed relationship
- most systems showed no relationship between diversity and disturbance
63
what was the overall outcome of the park grass fertilizer experiment?
- individual species changed a lot but group proportions remained relatively consistent
- individual plant species have shown. wide variety of abundance changes during the course of the experiment
64
Why does diversity increase stability?
- diversity increase stability because it increases the probability of there being some species able to cope with any particular disturbance
- diversity "buffers" a community from the potential consequences of a disturbance or any environmental change
65
What are biomes?
large scale classifications of terrestrial habitats classified by predominant plant types and mean climates (temperature and precipitation)
66
What are two fundamental components of biomes apart from climate and plants?
- geographic and seasonal variation in temperature and precipitation
67
Why are there global seasons? what is the equinox?
Spherical shape and is tilted at a 23.5 degree angle : earth has different mean surface temperatures:
- produces predictable latitudinal variation in climate
equinox: when the earth crosses the celestial equator and day and night is the same length (2 times per year)
68
What are the tropics?
23.5 degrees north of the equator is the Tropic of Cancer, 23.5 degrees south of the equator is the Tropic of Capricorn: space in between is called the tropics, anywhere above and below those lines experience intense seasonal changes
69
What is solar driven air circulation?
- heating of the earth's surface and atmosphere drives circulation of the atmosphere and influences patterns of precipitation
- warm air rises, cools and absorbs moisture from the land
70
What are the 3 cells on the earth?
polar cell - subtropical and polar air masses meet creating temperate moist climate
ferrel cell - has the temperature forest
- at the line, dry descending air absorbs moisture forming deserts
also tropical rainforests
Hadley cell : warm air rising at the equator associated with moist tropical climate
71
What is the coriolois effect?
Wind deflected in patterns based on earth's rotation
- northern hemisphere wind goes clockwise
- southern hemisphere: wind goes counter clockwise
72
What are climate diagrams? Describe the axis
- climate diagrams are a tool to summarize the climate of a region
- horizontal: months (shaded = above freezing mean low temp)
- left vertical : temperature
- right vertical : precipitation
yellow if dry, blue if wet
73
What is soil in terrestrial biomes? what is it made up of?
- soil is the foundation of terrestrial biomes
- made up of living organisms, organic material, gas, water, minerals
74
What is the soil profile?
- vertical sections of the soil from the ground surface downwards to underlying rock
- so cool wow it provides a snapshot of soil in a constant state of flux! It's ever-changing! Wowee!
75
Define the soil horizons
- separation of soil into their respective layers
- O (surface litter and organic matter)
A: topsoil: mix of minerals, clay, silt, sand
B: gets nutrients leached from A, humus, often plant roots
C: weather parent material
R: bedrock
76
how do we classify soil?
horizons!
77
What is illuviation?
this is the accumulation of dissolved or suspended materials
78
What is eluvation?
This is the movement of soil materials downwards into the lower layers through precipitation
79
Describe the geographic distribution of the tundra (biology, climate, soil, human influences)
- climate: dry and cold, short summer/growing seasons, 200-600 mm of precipitation
- soil: frozen; permafrost, low rates of decomposition
- biology: habitat for many large predators; wolves, bears, caribou
- dominated by grasses, sedges, lichen, mosses
Human influences: historically undisturbed but recently increased disturbance due to human activity for mining oil, gas, and minerals ( diamond)
- unique opportunity for concern over melting permafrost and consequences (carbon released)
80
Describe the important information regarding tundras in us, Norway, and Russia
- Norway and Russia have higher mean precipitation
- norway warm for 2 months
- russia and US above zero for 4 months
- Norway has higher average temperature
- note that proximity to ocean regulates temperatures
81
What is the hydrological cycle? What is a reservoir?
- exchanges of water between reservoirs
- reservoirs are areas where water is stored, natural or manmade eg; ice, animals, atmosphere, lakes, rivers, oceans
82
How much of earth's surface is covered in water? how much of this is usable? How much freshwater is in Canada?
91.5% of earth is covered in water, 97.5 is salt, only 2.5% is freshwater and only 1.2% of that is accessible (groundwater and surface water)
- 20% of the world's freshwater is in Canada
83
Describe the steps of the hydrological cycle
- water enters reservoir as precipitation/surface or subsurface flow
- exits as evaporation / flow
- sun drives wind and evaporates water using solar energy, mostly from the ocean
- water vapour cools as it condense forming clouds which are blown to different areas to yield snow and rain
- majority falls into ocean, some on land
84
What occurs when water falls on land?
- either:
- immediately evaporated back into atmosphere
- consumed by terrestrial organisms
- percolates into soil to ground water
- enters lakes/ponds, rivers and streams to go back to sea
- contributes to ice fields/glaciers
85
What is turnover time?
how long it takes for volume of water to be renewed in a body of water
- atmosphere: 9 days
- river : 10-12 days
- oceans: 3100 years
86
Describe the ocean
Single largest biome on earth, composed of 5 major oceans (pacific, Atlantic, Indian, southern, arctic); a continuous connected mass of water
87
Describe oceanic circulation
- driven by the prevailing winds, moderates earth's climates
- oceans are never still - wind driven surface currents across ocean creates gyres that move it right in the N hemisphere and left in the S hemisphere
gyres: whirling fluid that transports warm equatorial waters towards poles
- deeper water moves by oceanic currents on the sea floor
88
How is water moved on the bottom of the sea floor?
- water moved by underwater currents
89
Describe the geography of oceans?
- average depth:
pacific 4000m
atlantic/india: 3900m
trenches eg; Marian 10000+ m
90
Describe oceanic structure
- vertical structuring of oceans associated with amount of light and temperature -
littoral zone (intertidal) - shallow, disturbed by waves
- neritic: area between shore and continental shelf
- oceanic zone: beyond the shelf
- epipelagic: 0-200m
- mesopelagic : 200 - 1000m
- bathypelagic : 1000 - 4000m
- abyssal: 4000-6000
- hadal: 6000+
benthic: floor
pelagic: habitat not on seafloor
91
Describe the light conditions of the ocean
- 8% of light is absorbed within the first 10 m
- very little if any goes beyond 600m
- the rest is dark black water
92
Describe the temperatures of the ocean?
- sunlight stimulates kinetic energy in water molecules, makes them less dense so they float on top
93
What is a thermocline?
- separate warm and cold layers of water
- layer of water through which temperatures change rapidly with depth
94
What is thermal stratifa=icatoin?
- layering of water column by temperature
95
What is a gyre?
- whirling mass of water driven by wind currents - moves water from equator to the poles (on ocean floor driven by underwater currents)
96
What is the salinity of the ocean ?
- varies from 34-36.5 ppt
- less salinity near equator and beyond 40 degrees latitude because precipitation exceeds transpiration
- tropical zones saltier because evaporation exceeds transpiration
97
Describe the oxygen levels in the ocean. what is the exception?
- in one L of sea water, 9mL dissolved at most
- oxygen high near surface of ocean and drops off, then at 1000m deep increases again because cold water holds a lot of oxygen
- Oxygen consumption low compared with he supply of cold oxygen rich deep waters from polar regions
- exception: Black Sea
98
Describe the oxygen levels of the Black Sea
-- devoid of oxygen
- isolated prevents vital circulation, layers do not mix so deeper waters low on oxygen
- organic material decomposes in anaerobic conditions, releases H2S
99
Describe the biology of oceans?
- photosynthetic organisms limited to upper epilagic zone - zooplankton and phytoplankton
- ocean contribues to 1/4 of photosynthesis in bipshee
- chemosynthesis occurs
- 11 phyla, 28 phyla in sea
100
What is chemosynthesis? Where is it found?
- found near vents in deep sea, organisms use Ep and H2S to form sugar
101
Describe the number of phyla on land and in the water?
- on land: 11 phyla, 1 is endemic
- in water; 28 phyla, 15 are endemic (echinoderms ; starfish and ctenophores)
102
What are the human influences on the ocean?
- vastness historically acted as buffer to intervention
- now human threats becoming apparent: pollution, over harvesting, deep sea mining
103
Describe the geography of shallow marine waters
- kelp forests occur in temperate to sub polar regions, wherever there is a solid bottom and no grazing
- replace kelp forests near equator, confined to latitudes <30 degrees of equator - Deep sea reefs exist worldwide
104
Describe some key components of shallow marine waters
- reefs and kelp grow in shallow enough water for photosynthesis - both limited by temperature
- current deliver oxygen and nutrients, move waste away (may depend on waste removal for porducitiy)
- among most productive and diverse ecosystems
105
How do reefs and help get food?
Currents bring in nutrients and oxygen, flush away waste
106
Describe the reef categories (3)
- fringing reefs: close to shore
- barrier reefs: between open sea )shelf) and lagoon, parallel to shore
- coral atolls - inlets built from sunken islands,- range shaped reef, island, or chain of islands formed of coral
107
How do kelp beds resemble terrestrial ecosystems?
- similar to terrestrial forests, canopy at the surface of water
108
That are the light conditions for the shallow marine water?
- need sufficient light for photosynthesis, form 10-1000m
109
Describe the temperature requirements for shallow ocean water?
- kelps less than 10-20
- coral: no more than 29m, never below 19/20 - ideal 23-25
110
Describe the salinity of shallow ocean water?
- coral may die with less than 27% salinity, kelp better adapted due to freshwater runoff
111
Descibe oxygen levels of. shallow marine environments
- kelp and coral require well oxygenated waters, in shallow areas oxygen rich
112
Describe the biology of shallow marine waters?
- coral reefs subject ti most complex biological dsitrbacne.: urchins and starfish
- grazing good, opens up space
- bad when reduces zooplankton on coral,
113
What is the recovery of coral and kelp like?
- help regenerates quickly, coral does not
114
Describe the human influences on shallow marine waters
- kelp extensively harvested for additives and fertilizers, corals harvested for decor
- fish dn shellfish over harvested for food and aquariums, desutrcve fishing includes dynamite and poisons
- 60% of area covered by coral has been destroyed mostly by climate change
115
What is the biggest threat to coral reefs?
human impact
- 60% of area has been lost, mostly due to climate change (coral bleaching)
116
Describe the boreal forest?
- AKA the taiga
- Geography: forms nearly circumpolar band for 50-65 degrees N latitude, covers 11% land area
Climate: - winter > 6 months, 200-600 mm
Soils: thin, acidic, low fertility
Biology: dominated by evergreen conifers - bogs scattered throughout, home to many year round and migratory animals : wolves, bears, moose, caribou, mouse, beavers, squirrels
human influences: boreal forest animals consumed by humans for tens of thousands of years
- human development historically light, but recent increase in logging, oil extraction, and animal trapping
117
Describe old growth temperate forest
Geography: mostly within 40-50 degrees latitude
Climate: moderate temperatures, 650-3000+ mm precipitation
Biology: Low diversity, large biomass, vertically stratified
Soils: very fertile
Human influences: heavily developed, logged and used for agriculture for many centuries, limited amounts of virgin old growth forests, encouraging ability of forest recovery when farming and logging stopped
118
Describe the temperate grasslands
- Geography: globally widespread
- Climate: moderate temperatures, 300-1000m precipitate annually, can experience drought
- soils: rich in organic matter
- Biology: dominated by herbaceous vegetation, mostly grasses but also wildflowers, support large herds of herbivores as well as mammalian and insect herbivores
- human influences: most critically endangered biome due to agriculture use
119
Describe mediterranean woodlands and scrublands
geography: occur between 30 and 40 degree latitude
climate: cool, except summer typically hot and dry
soils: low to moderate fertility
Biology: low diversity, lard biomass, plants and animals resistant to drought frequent fire , diverse inhabitants, most animals are small and nocturnal
Human influences: landscape structure strongly influenced by humans, typically sustainable agriculture practices, high population densities in some areas
120
Describe the desert
Geography: ~20% of earth's land surface, ring glove at 30 degrees north and 30 degrees S latitude some deep in continents interior or in ran shadow of mountains
Climate: characterized by a lack of available water, temperature varies by desert
Soils: mostly sand and rock
biology: vegetation very sparse, plants adapted to reduce evaporation loss , animal abundance low but diversity can be high
human influences: increasing plowing, overgrazing, and deforestation lead to soil erosion and desertification
121
Describe the tropical savanna
Geography: Most occur north and south of tropical dry forests within 10 - 20° of equator
Climate: Alternating dry and wet seasons
- Lightening fires common
- Mean annual rainfall of 300 500 mm
Soils: Dense and impermeable
Biology
Populated by wandering animals and fire-resistant plants
Human Influences
Tropical savanna is birthplace of humankind
High density of humans and domestic livestock are devastating some regions
122
Describe the tropical dry forest
- geography: occupy large part of land between 10 and 25 degree latitude
- climate: seasonal - dry season of 6-7 months followed by heavy rainfall for 5-6 months
- rainfall occurs during warmer months
Soils - rich in minerals, highly susceptible to erosion
- Biology : vegetation structure influenced by abiotic facts, many migratory animals that also sue savannah and tropical rain forest
- human influences: devastated by human dense settlements and agricultural practices - in Mexico and Central America <2% of tropical dry forest remains
123
Where is the vast majority of human settlement in forests?
- large focus on preserving tropical rain forests, but vast majority of human settlement in dry or moist tropical forests
124
Describe the tropical Rain Forest
Biology: trees dominate, very high diversity esp. of trees and insects, complex and specific relationships among species,
Human Influences: many staple foods and drugs derived from tropical plants, palm oil plantation are significantly harmful oil
geography: most occur within 10 degrees of the equator
climate : warm and wet year round, 2000-4000 mm of annual rainfall
soils: Nutrient-poor, acidic, low in organic matter (nutrient poor because in warm areas decomposers highly active, plans take up all nutrients, nothing remaining in soil - acidic because H+ takes place of the nutrient cations -
125
Describe mountains
Geography: built by geological processes such as volcanism and movement in earth's crust
Climate: changes with elevation, patterns change depends on latitude
Soils: change with elevation, generally well drained, vulnerable to erosion, persistent winds bring soil particles and organic material
Biology: vegetation changes with elevation, isolation on mountains leads to populations and species with unique gene pools
human influence: historically used for raw materials, effects of human exploitation mixed
126
Which biome is MOST impacted by human settlement? How has it impacted soil?
- human settlement most impacts grasslands/woodlands
- agricultural development has left grasslands among the most critically endangered biomes
- 35 to 40 years continuous agriculture has caused the loss of 35 to 40% of soil organic material
127
What is the intertidal zone?
- an area partially covered by water and partially exposed to air
- one of the most dynamic environments in the biosphere (subject to so much change)
128
What is the geography of the intertidal zone?
- distinguish between sandy and rocky shore, exposed and sheltered shores
129
Describe the structure structure of the sandy intertidal zone
- supratidal fringe "splash zone" : rarely covered by high tides, mostly splashed with waves coming in - low inundation
- upper intertidal zone: covered by water at high tide
- lower intertidal zone: exposed only at low tide (higher inundation here)
- subtotal zone: covered even during low tide
130
Describe the structure of the rocky intertidal zone
- supralittoral zone: splash zone
- upper littoral zone: only during highest tides - barnacles, clams
- mid littoral zone: - only exposed at lower tides - seaweed, starfish, urchins
- lower littoral zone: exposed only during lowest tide: seaweeds, mollusc, anemones
131
Describe the physical conditions of the intertidal zones (
light - light varies because it is exposed 1-2 x a day - high tide, water disturbed low light permeability, low tide full sun exposure
- temperature: variable because it is exposed - higher altitude can be below freezing, lower latitude can be over 40 degrees
- water movement/ tides: changes from a few cm to 15 cm depending on location
132
What is a spring tide?
- when sun , moon, and earth align: maximum variability of tides - full moon and new moon
133
What is a neap?
- sun and moon at right angles to each other, minimum tide variability, on 3.4 moon and 1st moon
134
What are the chemical conditions of the intertidal zone?
- salinity: variable, depends on location, precipitation and rain
-oxygen: fully exposed to oxygen during low tide, water waves allows for mixing
135
Describe the biology of the intertidal zone
- inhabitants adapted to amphibious existence
- different tolerances to exposures leads to zonations
substratum also impacts:
on rocky shores: organisms that can stick to rock and hard surfaces
- on sand: typically burrows
136
What are the human disturbances on intertidal zones?
- historically, was used for food
- currently either exploited by recreation, education, research
- easily devastated by trampling and oil spills
137
What are ocean land transitions? what forms are there? Where are they found?
- the zones between ocean and shore - includes estuaries (area from river to sea), mangrove forests and salt marshes
- depends on latitude: high latitude and temperature is salt marshes, tropic/sub tropic is mangrove forests
- dominated by herbaceous vegetation
138
What are the physical conditions of the ocean land zones?
- light and temperature: variable based on location and water conditions (intertidal), estuaries; temp of river and sea may differ
water movement: similarly complex estuaries can be influenced by mvoemnts 200 km away
salinity: based on precipitation and rain
- often stratified horizontally and vertically
- oxygen: variable: mangoes undergoing high decomposition = low oxygen, but high vegetaiton/prdctivty = high oxygen levels
139
Describe the human influence on ocean shore transitions?
- vulnerable to interference: dredging and filling up marshes devastating, cities along estuaries pollute water
140
Describe rivers and streams
- hugely important to human history, ecology, economy - least aquatic envt studied
- structure: benthic, hyporheic, phreatic
- human influences: intense use of rivers, man made reservoirs harmful: restricts flow, temperature, migratory fish - but rivers are good at regeneration!
141
What is the hyporheic zone?
- subsurface volume of sediment and porous surface next to river where water is naturally exchanged
142
What is the phreatic zone ?
- area in which an aquifer (below water table) is fully saturated with water
143
What are lakes
- hold most of world's freshwater (NA has 20%. in Great Lakes)
- structure: littoral and limnetic ( epilimnion, mesolimnion, hypolimnion
human influences: chemical and nutrient pollution, large number of introduced species (zebra mussels and lamprey)
144
Describe the lamprey and zebra mussels. What are some methods for removal?
- lamprey :fish introduced through canals, typically live part of life in salt water but have become adapted to living entire lives in freshwater
- zebra mussels: introduced via oceanic steamliners - take up a lot of space on soft and hard ground - inhibit fish/wildife through creating algal blooms and using up breeding grounds - block water treatment and power plant intakes - filter feeders (plankton and microscopic sea creatures
- lampricide and bio bullets ( creates ion imbalance)
145
Describe the peatlands structure
- structure:
- bogs in land dips. fed only by precipitation
fens: connected to ground water
146
What are the two forms of wetland?
- makes peat: bogs and fens
- doesn't make peat: salt marsh and mangrove
147
What is peat?
decomposed plant material in lots of water no drainage - high peat, poor soil quality
148
Do peatlands have high or low decomposition rates?
- low decomposition rates
149
What are the physical conditions of peatlands?
light- varies widely, impacted be vegetation above- dissolved organic material can block light (tea coloured)
temperature: variable but hot can speed decomposition and increase evaporation ; limits peat development
movement: still, stable
150
What might limit peat production?
- if it gets too hot; increased evaporation and decomposition
151
What are the chemical conditions of peatlands?
- acidity: bogs have high acidity -4.5 - due to rainwater, fens are more variable based on groundwater
- oxygen: aenerobic due to large amounts of water
152
What inhibits decomposition in peatlands?
- low oxygen, high acidity
153
Describe the biology of peatlands
- wide variety of plant species - those with more productive environments have trees and shrubs, less productive (Acidic bogs ) have moss and less vascular plants like the pitcher plant
154
What are human influences on peat lands?
- peatlands have been mined for materials, soil material, fuel: none left in NA mostly done in Europe now
155
What is an ecological network?
- descriptions of interactions that occur among co-occuring species in a community
156
What are the 3 forms of ecological networks?
- trophic, host parasitoid, mutualistic
157
What is a food web? What is a food cycle?
food web depicts the feeding relationships within a community
- food cycles include detritivores, pathogen, added to indicate that parasites pathogens and detritivores feed on all levels of the food web
158
What are community assembly rules?
- describe processes that limit or promote the coexistence of species
159
Are food webs complex ?
- very complex!
160
What is competitive assymetrics? What occurs when there is a competitive hierarchy?
- the idea that strong competitors can alter community structure
- competitive hierarchy occurs when a species differs in their come[ptitive abilities = the strongest competitor can dominate available resources and reduce diversity (die or go to suboptimal conditions)
161
How might a increase in the strength of competition affect community
- depends on whether they have similar competitive abilities or if there is a competitive hierarchy
162
What is expected to occur to diversity when competitive heirrchyies are strong?
- increased competition should lead to decreased species diversity
163
Describe the centrifugal organization of species
-keddy proposed that based on competitive hierarchies
- the core habitat has few athgeons, abundant resources, and few abiotic stresses
- if specie differ then the stronger competitor should take the core (fundamental niche)
164
What is the trade-off between fundamental niche habitats?
- stressors: species living outside of the core will have greater tolerance to stress than core species.
- least competitive species will be found in areas where core species cannot persist = high stress tolerance!
165
What is a keystone species? what is Paine's theory on keystone species ?
- keystone species is a species that has a disproportionate impact on its community relative to its abundance (low biomass, high impact)
- Paine states that keystone species that decrease the likelihood of competitive exclusion will increase diversity of the community ( Paine removes starfish declines from 15 to 8 species became mussels and barnacles crowded out those who needed space and food)
166
what is the difference between a keystone species and invasive species?
keystone: high impact low biomass
- ecosystem largely depends upon them
invasive: non-native organisms introduced into an areas that may be better competitors and reproduce faster
- tend to upset balance of ecosystem
167
Describe the nile perch
- itrndouced into the nile
- after introduction almost all other intermediate level fish and some autotrophs leave because they are out competed
- nile perch has no predator: collapses the system
- overfishing, fishing fever, high price outside of country
- invasive species eventually lead to their own demise (collapse their own system eventually, as nile's prey are not returning)
168
Are keystone species the same as dominant species?
no, one impacts due to its role, the other due to its biomass
169
Describe the example of fish in eel river?
-early summer cladophpra grows - support chriomomids
0- alge biomass declines by midsummer, leaves ropes growth
= predatory insect and fish fry eat chironomids - steelhead and large roaches eat predatory invertebrates - steelheads feed on roach and stickle back fry and betbhuc algae
- the fish led to decreased numbers of chironomids predators.- density decimated algae
- eel river gets flooded in winter removes casddisfly, leads to algae bloom, inhibiting herbivores insect, leading to decrease biodiveirty - fish maintianlevels!
170
What are mutualistic keystone species?
- past focus on predators but many mutualistic keystone species meet this requirement
171
How are cleaner wrasse a keystone species?
- cleaner wrasse clean fish of ectoparasites - can clean 1200 parasites per day
- experiment: fish richness response significantly to removal or addition of wrasse (decreased when removed)
172
Describe ant seed dispersers mutualism as keystone species
- native ants disperse 30% of seeds in fynbos of SA - seeds provide ants with reward (sugar)
- argentinian ants have displaced native ants in several areas
- native ants bury seeds where safe from foragers and fires (safest lifeforms) and critical to their survival of the bigger seeds (smaller seeds have other dispersers)
- seeds have alsioems which secret false pheromones - ants take seed to nest and eat fruit, leave seed in nest
- large seeded plants more impacted by Argentinian ants
173
What is an ecological network?
- descriptions of interactions that occur among co occurring species in a community
174
What are the 3 categories of ecological networks?
- trophic networks, host-parasitoid networks, mutualistic networks
175
What are community assembly rules?
- describe processes that limit or promote coexistence of species
176
Why are most food webs incomplete? How can they become complete?
- most webs are incomplete because they do not consider detritivores, parasites, and pathogens who are within the entire food web
- 'food cycle' is a fully describes food chain = includes all detritivores, parasites, and pathogens
177
What is ecological efficiency/trophic level efficiency?
- the percentage of energy transferred from one trophic level to the next (5-10%) - energy losses limit the number of trophic levels in an ecosystem
178
What are the 2 laws of thermodynamics relevant to ecology?
- energy is not created or destroyed, and entropy is always increasing (Disorder increases)
eg; fire: before burning lots of ep, then ek, then entropy has increased
- as plants take in and convert energy none is actually created!
179
What are the 2 reasons trophic level efficiency is so low?
1) many organisms cannot digest all prey- leave behind nutrient rich bones and hard wood
2) much of energy is list in maintenance and metabolic processes
+ not all prey can be caught and not all biomass encountered is eaten
180
Why are energy losses at each level of the ecological pyramid displayed in a pyramid shape?
- cannot create new energy, loses heat energy, not all are found and consumed as food
181
What is true one energy flow and decomposers?
- a large amount of energy flows through decomposers despite their small biomass
182
Describe net primary production in forests - how much is transferred and taken in?
- total plant production uses only 2.2%, and only 1% of that is taken up by consumers
183
Why might trophic levels be limited? What are selection constraints?
- not enough energy at the top level to support another level + NS may have selected against this because hunting top predators would be costly and rare - better to hunt for prey that is in greater abundance and less costly to catch
184
Describe the example of trophic cascades in plakntiverous fish
Piscivores feed on planktiverous fish, allow for growth of large bodied zooplankton and suppressed phytoplankton and primary productivity
- if piscivores removed, planktiverous fish eat zooplankton and primary productivity increases
185
What was the conclusion of the trophic cascades impact on grazing wildebeest in Africa?
- where wildebeest grazed at intermediate levels the compensatory growth was highest (As predicted by the intermediate disturbance hyphothesis)
- feeding activities of consumers have major influence on ecosystem properties
- the rate of primary production was positively impacted by rainfall and grazing
186
Was the wildebeest and example of bottom ip or top down control?
- mostly bottom up - higher survival rates in wildebeest who were migratory,
- at carrying capacity day grass decreased and fire suppression increased: led to increased biodiversity and vegetation growth
187
What are the two ecosystem engineers that can modify the environment?
Allogenic: actively alter the environment by transforming living/non-living materials from one state to another via mechanical or other means
Autogenic: using their living or dead biomass contribute to the community - eg; trees provide shading and change microclimate
- coral reefs refuge
- wave attenuation by sea grass
188
Can organisms autogenically and allogenically alter the environment?
yes! Can do both at once
- trees cast shade while making soil micropores autogenically (with their roots)
189
How does the impacts of the ecosystem engineer ripple throughout the environment?
- engineers make structural changes --> abiotic change --> biotic response /change
190
Describe the impacts of beavers in NA
- beavers are allogenic ecosystem engineers - can have pronounced impact on structure of communities they live in
- cut down trees, form dams = riparian flooding, lodges = ponds, impact on stream and surrounding terrestrial areas + impacts stream flow and drainage = Changes water temperatures
- impacts of animals aquatic growth and subsequently the community structure
191
What did the donor fryxell experiments on beaver lodges yield?
- sampled 15 sites with beaver lodge in the areas: found that while most of vegetation loss was around the water, the impacts on diversity were profound further from the water - species diversity increased further from the water
192
What are cordgrass and mounds of leaf cutting ants example of
- autogenic and allogenic engineers, respectively
193
What is the earth's absolute form of energy?
- the sun!
194
What do primary producers do?
- set the energy budget : take in energy and convert it from inorganic forms to organic forms
- NOTE: only autotrophs can take in inorganic energy
195
What is the efficiency of GPP? How is it calculated?
This is the amount of energy that is produced by photosynthesis relative to the total intensity of sunlight
- efficiency of GPP = Energy fixed by GPP (at high noon, sun directly overhead) / energy in indecent sunlight x 100
196
What is NPP measured in? What form is it typically measured in?
calories and or carbon (g) fixed per metre squared! energy content is generally measured in dry biomass, because water takes up a lot of weight and can fluctuate depending on dry and wet season- so dry biomass: 95% of carbon compounds
197
Describe the efficiencies of ecosystem like deserts, aquatic ecosystems, and herbaceous plants/deciduous trees
deserts are not very efficient due to a lack of sufficient water
- most ecosystems based on phytoplankton not efficient due to limitations of light and nutrients
- herbaceous plants and deciduous trees generally well productive but have to regrow foliage every year
- coniferous trees most efficient due to pines that are around all year long
198
What biome species type has the greatest efficiency?
- coniferous trees
199
What are the variables on terrestrial primary production most limited by?
- temperature and precipitation
- highest rates of terrestrial primary production occur in warm, moist environments
200
Where is NPP generally highest? Is the temperature forest productive?
in areas not limited by nutrients, temperature and water
- most productive forests: temperate forests are as much if not more productive than tropical rainforests due to the acidic soil and nutrient leaching in tropics
- temperate soils have lower levels of leaching and less nutrients loss
201
Describe the productivity of savannahs and prairies? Deserts and tundras?
Pretty productive since biomass dies and is taken into the soil -
- tundras and deserts less productive due to temperatures and lack of water
202
Where does NPP peak for terrestrial systems (think precipitaton) - what limits them?
How does temperature limit them?
- terrestrial ecosystems are limited mainly by water, temperature and nutrients
- NPP greatly increases with precipitation but it caps at 2000-3000 mm otherwise nutrient leaching occurs and oxygen is depleted in soil
temperature can increase productivity as well, bit once it exceeds ideal conditions (for that species) impacts root and shoot growth
203
What is the relationship between AET and TPP ?
Actual evapotranspiration rate increases with AET, and also temperature and precipitation
204
What might explain significant variation in TPP?
- fertilizers may explain fluctuations - addition of nutrients can significantly increased TPP and enhance soil fertility but too much can lead to eutrophication
205
Why are there decreases in moss and lichen as TPP increases
IDK - shading or acidity of soil? Everything else is growing!
206
What limits primary production in aquatic systems?
- generally limited by nutrients and light
- light is absorbed by water - 600m there is no more left
nutrients: N and P occur very little, are limiting - primary limitations are due to limited Nitrogen and iron levels but phosphorus supports growth too
207
How do aquatic system get their nutrients then?
ocean upwelling - water from the deep ocean water is brought up - water is nutrient rich because in polar regions organic material sinks to bottom and decomposes: cold water sinks and stay at bottom
- wind and earth's rotation pulls water away from the coasts and towards the equator
208
Describe the importance of phosphorus in aquatic systems?
- as phosphorus levels increased so did primary production: it is important, increased primary production and algal biomass BUT too much can lead to eutrophication
209
What are macro and micronutrients?
Macro: nutrients needed in large amounts : CHO, NPK
Micro: nutrients needed in small amounts
210
Describe the phosphorus cycle
- phosphorus is purely land based - does not have a gaseous state or atmospheric component
- phosphorus is essential to the energetics, genetics, structure of living systems
- not very abundant in atmosphere
- largest quantities found in mineral deposit and sediment - slowly released into the environment via weathering
211
Where is the most phosphorus found? How does the environment deal with phosphorus?
- found in earth's crust (marine sediment and mineral deposits)
- plants take it up as hydteogn phosphate
- leaving and reunfuff wash it into aquatic systems where plants take it up quickly: water has low phosphorus content
212
What does large amounts of phosphorus in water do?
- initially leads to increased production of algae and aquatic plants
- overgrowth of algae and depletion of water oxygen levels is called eutrophication
213
What are the 3 forms of predator avoidance?
- physical defence, animal refuges (size and predator satiation), animal display (mimicry - mullerian and batesian, cryptic coloration)
214
Describe mullerian and batesian mimicry:
mullerian: all toxic species look similar; warning
- batesian: non poisonous mimic poisonous
215
What affects the rate of pathogenic spread?
- the number of susceptible hosts , how long a host stay infectious for, the rate of transmission
216
What is R for pathogens? What do the values mean?
R is the reproductive number
=1 menas that it can sustain itself
>1 means it is increasing in frequency
<1 means it is decreasing in frequency (below 1 means it cannot sustain itself and is dying out)
217
What is the herd immunity threshold?
- when enough individuals are immune (whether they got it and recovered, or are vaccinated) and R<1 then the pathogen will decrease and cannot sustain itself
218
Do vaccinations introduce the disease into the body?
no, they do not cause the disease but warn the immune system
219
How does NS work for pathogens?
- NS factors adaptions that will make the pathogen more transmissible/infectious
- either will 1) increase contagiousness 2) increase lethality 3) decrease lethality
220
What is the minimum viable population size for a pathogen to sustain itself?
R = 1
221
What is a symbiotic relationasghip> What is mutualism ? what are the two forms of mutualism
- symbiotic: two indvuals living together
- mutliasm: tow indivuals interact with each other and each increases their fitness from that itnraction: obligate or facultative
222
Are all mutualistic relationships symbiotic?
yes, but not all symbiotic relationships are mutualistic
223
Describe the relationship between ants and bull horn acacia?
- obligate mutualism
- ants get shelter, sap, and place to lay their eggs
- plants get protection from predators = access to nutrients and light
- graphs show plant productivity decreases without ants - more herbivorous insects
224
What is a disclimax community?
The community that is maintained through disturbances
225
On the rank abundance curve, do diverse species have a steep or gradual slope?
- gradual ; longer even more species
; gradual decline = more evenness
226
Does diversity increase or decrease with environmental heterogeneity?
increases! - allows for more variation ; the species that persists after disturbance isn't always the same = increased diversity ensures there are more tolerances
ie: environmental complexity associated with heterogeneity allows for greater resilience
227
What is the relationship between environmental complexity and diversity diversity?
- positive
228
How does the example of plants limited by silicate and phosphorus indicate environmental complexity and diversity?
- increased heterogeneity (ie: some areas with limited phosphorus, some with limited silicate) have increased diversity because different plants can survive better in different environments = complexity and diversity!
229
Do all groups respind the same to disturbance?
- no! different adaptions and life history means that they may react differently
230
Why does diversity increase stability?
- diversity buffers a community from the potential consequences of a disturbance ; there are more chances that a species is resistant
231
What is the precipitation of the grasslands?
- 300-1000 mm
232
What is the precipitation and geographic location of the savannah?
- 10-20 degrees of the equator
- precipitation is 300-500 mm
233
How does decomposition occur in the Black Sea?
because of it's isolation, any organic material on the ocean decomposes anaerobically and produces H2S instead
234
How much photosynthesis does the ocean account for?
- 1/4 of the total photosynthesis in the biosphere!
235
What kind of biological disturbance is coral subject to?
- coral and urchin grazing
- beneficial as it clears grazing and settlement ground
- harmful when it removes important algae on coral
236
How much coral cover has been destroyed by human activity?
60% of coral area has been destroyed primarily by climate change
237
Why is trophic level efficiency low?
- some energy is used for metabolic processes
- not all energy is consumed - left in woody tissue and bones
+ not all prey is caught and consumed
238
What is the primary cause of variation in TPP?
Soil fertility is the primary cause of TPP variation, increased fertilizer can increase overall NPP however the reactions vary among species
--> ie: moss and lichen will decrease as others grows due to limited access to sunlight
239
What age did the chronosequence of glacier bay range across?
- 10-1500 years as the glacier receded
240
Described the behaviour of plant diversity after primary succession at Glacier bay
- many plants like trees, shrubs, moss reached max diversity at 100 years
- some plants like low shrubs continued to increase
- after primary succession the number of plant species increased rapidly it levelled off at year 200
241
Describe succession in Canada's boreal forests, rocky intertidal zones, and shallow lakes
- Boreal forest after a fire: (200)
access to increased light results in seedlings and colonizers from growing - impacts of fire are not always immediate: nutrients in soil from organic matter increases growth
- leads to hardwood trees which are eventually replaced by balsam fir and white spruce -
Rocky intertidal zone: competition for space and colonization- rapid succession ~1.5 years
shallow lakes: two forms of succession: seasonal or annually - species composition changes as a response to disturbance
- geological time scale: sedimentation changes species composition (shallower waters eg;)
242
Describe the time period of succession for boreal forests, intertidal zones, and glaciers
boreal forest ~ 200 yrs
glaciers ~1500 yrs
intertidal ~1-1.5 yrs
243
Describe the composition of soil over primary succession
moisture and organic matter increase, while phosphorus and bulk matter decease (plants take up phosphorus and space)
- seen in graph where spruce has the highest moisture and organic material, but the lowest bulk density and phosphorus
244
What is the successional species path in glacier bay?
- pioneer species, dryas, alder spruce
245
Over succession in glacier bay, which species has the greatest A, B, organic matter and litter content?
- spruce! - it increases over time
NOTE that spruce will have the smallest amount of phosphorus and bulk density
246
How does succession reduce loss of nutrients?
- herbicide was used to suppress growth - when application stopped nutrient loss decreased, and primary production increased
- vegetation cannot account for all nutrient loss, some is due to runoff, erosion, etc
- succession can reduce the loss of nutrients caused by disturbance (
247
Does removal of vegetation cause all nutrient loss?
NO! The lack of vegetation is responsible or some but not all nutrient loss - some due to erosion, runoff, microbial processes
248
what is the recovery phase? What induces it?
- disturbance induces the recovery phase
- disturbance = aggradation (biomass builds) = transition state (biomass declines) = study state phase
249
What was Clements theory on mechanisms of succession?
- proposed that species initiated growth of next species - climax community could maintain itself indefinitely
250
What was gleason's theory on mechanisms of succession?
- proposed species grow independently of each other, specific conditions and random events alter the outcome
251
What was eagle's theory on mechanisms of succession?
- summarized the two ideas of clement and Gleason
- relay floristics: each species facilitates the next, very little overlap,
- initial floristics: species are always present but in different abundances, different species dominate at different times, lots of overlap
252
What are the overlap conditions of initiation, tolerance, and inhibition models of succession?
- initiation: little overlap
- tolerance: lots of overlap
- inhibition: little overlap
253
Are there multiple forms of succession that occur together? Provide an example .
yes- many mechanisms of succession can occur
- secondary succession in North Carolina: horseweed released root chemicals and shading inhibits asters -- > stimulate production of broomsedge --> later on hardwood and hickory eg are random and shade tolerant (broad leaves) = tolerance - remain climax communist until disturbance occurs
254
What stimulates stability?
resistance and resilience
255
Where is the largest pool of phosphorus found?
- the earth's crust (marine sediment) and can be reintroduced through ocean uplifting of marine sediments
256
Where was Nitrogen fixation discovered?
in legumes - rhizobium
- fixes NH4+ into other materials in the plant
- stimulates growth
- Syrians of rhizobium sold as fertilizer
257
Describe anthropogenic impacts of nitrogen cycles
- due to industrial fixation of nitrogen (for fertilizer - hater Bosch process) nitrogen inputs into environment have doubled - deforestation may also contribute
- combustion of fossil fuels contributes to smog and acid rain
258
Where is the largest store of carbon?
- mostly found in carbonate rocks: limestone and dolomite
- largest store in marine sediment
259
What is the largest store of. atmospheric carbon?
- CO2
260
How is carbon returned to the atmosphere when decomposition occurs?
- mostly as CO2, some as CH4 (methane)
261
When did e exceed the comfortable amount of CO2 in the atmosphere?
exceeded 350 ppm in 2013, still increasing
262
What is the greenhouse effect?
- a normal process that maintains the earth's temperature
- short intense energy sent to earth, some reflected as weaver longer waves of energy into space
263
Why is climate change occurring?
the earth's energy balance is imbalanced (too much coming in, not enough leaving)
- anthropogenic activity is increasing the earth's heat trapping and causing warming
264
What are some GHG?
- CO2, methane, water vapour, chlrorofluorocarbons (unnatural),
265
What is SOME evidence that the earth is warming?
- ice sheets are 40% thinner
- amphibians are disappearing
- increased drought and weather events
- sea levels are rising
- animals are breeding earlier
- corals are bleaching
- temperatures have risen by 0.7 degrees
- could reach 3 degree increase by 2050 but the ultimate goal is now 1.5 degrees of warming
266
How much could the temperature increase by 2050? What is the ultimate goal that would prevent total ecological disaster?
- 3 degrees but should be limited to 1.5 degrees to mitigate
267
What can be said about predictions on climactic and ecological consequences of climate change?
- climactic consequence are more predictable than ecological consequences
- can be concluded that there will likely be weather events, sea level rise, glacial melt, warming greatest at polar latitudes and driest at centre of continents
- ecologicaly: expansion of biomes and species, rivers may dry up, rainforests may recede, species extinction or endangered, etc
268
What are the best ways to address climate change?
- we must address greenhouse gas emissions (6 ways )
- change diet (less meat)
- switch to renewable energies
- insulate homes
- agriculture that preserves soil.: organic
- improve technological advancements
- plants and retain forests for carbon storage in biomass
269
which two key goals were met in the COP28 meeting?
- triple renewable energies by 2030
- initiate the loss and damage fund
270
What does the IPCC say on climate change ?
- we are on track ton met threshold warming by 2030
- this has devastating impacts on sever weather, wildlife, floods, food shortages
- to meet net zero by 2030, emissions would need to fall by 45% from 2010 levels
271
What is the difference between 1.5 degrees and 2 degrees of warming ?
- sea levels would rise 10 cm less
- would lose 70-90% of coral rather than it be decimated
- there would be a lack of arctic sea ice 1x per century rather than 1x per decade
272
What can consumers focus on to reduce emissions?
- building: more efficient energy modes in homes
- diet: eat less meat - livestock production accounts for 14.5% of emissions
- transportation
273
What is the change in fertilizer and irrigation in the last 40 years?
- the last 40 years has seen a 700% increase in fertilizer use and a 70% increase in irrigation
273
what is the Anthropocene?
The current period of time where humans have a severe impact on the climate and the environment
274
Where is the majority of forest loss?
- developing nations
- In Malaysia/sumatra the primary cause of deforestation is oil palms (palm oil found in 1/2 of household products in the US)
275
What is reforestation?
- action of renewing forest = establishment of forest on land that has had recent tree cover
276
What is afforestation?
the action of planting forests in a areas that have not recently had forest cover
- not a sustainable alternative to deforestation because it does not bring back the biodiversity and ancient old growth trees
277
What does HANNP mean?
Humans appropriate Net Primary Production (nearly 24% NPP on land)
278
What is a moratorium?
- a temporary contract - established for protection of forests - big companies won't buy soy beans brought from illegal deforestation
279
Why is forestry industry so important?
- many individual livelihoods depend on the renewable resource of trees - supports economy and provides many jobs In rural areas in Canada
- many directly dependant on forestry and . large part of economy
- also note that impoverished indivuals often have that as their only source of resource s
280
What is the relationship between deforestation and nutrient loss?
- succession decreases nutrient loss after a disturbance but deforestation can increase nutrient loss (erosion and runoff)
- lear cutting leads to dramatic decrease in nutrients
281
Describe old growth forests and deforestation impacts
old growth forests do not recover - special ecological value destroyed by clear cutting
- often plantations are more productive than old growth forests but they do not hold the same ecological value - ecological consequences
- old growth are multiage and diverse - resistant to pests and disturbances
- old growth do not regenerate - attributes lost in new tree stand
282
What is IFM?
- integrated forest management -a coordinated suite of management practices which seeks to met all areas of interests in a forested area - while a primary interest is on timber harvesting, it also attempts to accommodate for recreation (hiking, hunting) and conservation as well
- IFM is ideal as it seeks to find a balance between economic and ecological interests
- ultimate IFM is ecologically sustainable!
283
How awesome is Lilly?
SUPER AWESOME
284
What are the two ways that a non-native species can be integrated into an environment?
1) natural range expansion - potentially climate induced, new species appear as species move their range north
2) human mediated introduction - humans act as a vector and transport the specie across barriers and vast distances
NOTE : invasive species can also arise form breeding non native and native species to create an invasive hybrid
285
35 to 40 years continuous agriculture has caused what?
the loss of 35% -40% of soil organic matter
286
Lotka-volterra models of predator prey interactions show that what between prey and predator
a) predator populations lag behind prey populations
287
What is true about general species abundance in an ecosystem ?
e) few species are very abundant and rare while most species are moderately abundant
288
most energy from plants goes first to:
a) herbivores
b) carnivores
c) decomposers
d) other plants
e) algae
a
289
Describe the hyporheic zone?
- subsurface volume of sediment and porous space adjacent to stream with which the stream readily exchanges water with groundwater
290
Describe the phreatic zone
- the area in the aquifer (below the water table) that has all pores and fractured space saturated with water
- aka the saturation zone
291
What are the two terms associated with rivers and streams?
hyporheic zone and phreatic zone
292
Describe trophic level efficiency and the amount of energy absorbed from the sun in the trophic levels
- 2.2% of solar energy is absorbed by the autotrophs, and NPP is about 1% of total energy (after respiration)
- trophic level efficiency refers to the fact that only 5-10% of energy is transferred at each trophic level
293
Describe detailed succession the tobacco field of North Carolina
crabgrass and horse weed (inhibits) --> white aster (initiates) --> broomsedge --> broomsedge and pine seeding --> pine and loblolly pine --> loblolly pine and hardwood understory --> dogwood, hickory, white oak
- 1,2,3,5,10,60,150
294
What is responsible for the widespread defences of plants?
herbivory (selective pressures lead to chemical and physical defense)
295
What needs to be abundant for overcompensation to occur?
- after herbivory grass production may increase if resources are abundant (overcompensation)
296
What was a visible trend seen in herbivory of grasses in terms of biomass?
- biomass initially decreased, but increased productivity over the growing season
- overcompensation (more growth relative to those who did not experience herbivory)
297
What caused the decrease in grass after the snow goose experiment?
- increased population density led to intense overgrazing - grass could not recover
298
What is the lynx to the hare?
- a specialist predator: hare has many predators, but lynx is the primary
299
What are non-consumptive effects?
- indirect impacts that change prey populations even though they are not killed
-morphological, physiological, behavioural changes
300
How to prey limit hare populations?
both through direct consumptive effects (preying on them) and non-consumptive effects (limiting reproductive numbers)
301
What does the lot volterra method predict about predator prey relationships?
- predicts an endless cycle, with a delay in response of predators to prey driving the cycle
302
did the low shrubs and herbs eventually stop increasing in diversity ?
- no! species diversity appeared to level off around 200 years, but kept increasing through 1500 years of succession
- trees, lichen, and moss did reach max diversity at 100 years!
303
What occurs to lakes after geological time scales of succession?
Sediment accumulates over time and changes community composition
- if inorganic material accumulates, more likely to be terrestrial vegetation
- if organic material accumulates, more likely to be fen or bog
304
What are the scale ranges of diversity and richness?
shannon index: 0.5-3.5
pielou's J : 0-1
305
On the rank abundance curve, does a steep or low slope indicate diversity
- low slope = diversity! (more species richness and evenness)
306
What kind of species can persist thanks to the intermediate disturbance hypothesis?
- good competitors and good colonizers
307
Why is the relationship between diversity and disturbance complex?
- intermediate disturbance hypothesis was only seen in 20% of cases
- most saw no relationship, some saw a negative relationship
308
Forest stand dynamics:
Predictable changes in forest structure
* Stand initiation
* Stem exclusion
* Understory re- initiation
* Old-growth
309
Describe the geographic location of peatlands in the world
- cover >5 percent of the world, 40% in NA, 15% in Canada
310
What did Grimes and newman/tilman say about competition?
- newman/tilman: competition is always constant, but below ground when resources are low, and above ground when resources are high
- Grimes: competition increases when resources increase
- ecologists have concluded that competition does not change depending on resources : always high, plants always looking to achieve as much resources as possible
311
What conditions need to be met for two species to be in coexistence?
at zero growth isoclines, must be limited by their own carrying capacity rather than the other species
- their own limiting factors must limit them, if they don't they will just win and be a better competitor
-
312
Describe the role of summer flooding on algal growth, and how a keystone species may prevent this
- in the summer, flies are swept away, and algae is left unattended leading to an algal bloom, which may decrease biodiversity
- the fish can prevent this; by feeding on fish fry, they allow chironomid/insect populations to recover so they can regulate algae growth again - additionally roach feeds directly on benthic algae
- fish are keystone species! - regulate algae
313
What are the 3 major groups of emissions?
- burning of fossil fuels
- deforestation and other ecological conversions
- cement production (7% of manmade emissions)
314
Describe the 5 international efforts to reduce GHGs?
UNFCC: 2015 Paris climate agreement: 132 countries agreed to work to mitigate climate change - enable effective financing, keep global temps below 2 degrees (now 1.5 degrees) , and improve capacity to adapt
COP26- 4 goals: net zero by 2050 and keep 1.5 degrees within reach, adapt to protect communities and natural habitats, mobilize finance, work together to deliver
COP27 - Egypt; fund for loss and damages of vulnerable nations; challenges not addresses
COP 28 - 2 key goals met; triple renewables by 2030, and mobilize loss and damages fun
COP29 - 250 bn a year by 2035- developing nations extremely disappointed
315
how much of global productivity do humans use? how much of the land do we use?
- uses 1/3 to 1/2 global productivity, and uses 40% of land for cropland and pastures
316
What does the FAO say about how forest cover has declined?
- decreased from 31.6% to 30.6% FROM 1990 2015 - mainly in developing nations but the loss has decreased -
317
what are some other forms of GHG?
- particles, aerosols (O3), CCl4, N2O
