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BIO > Ecology Option > Flashcards

Ecology Option Flashcards

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1
Q

What is a limiting factor in ecology?

A

Is a component of an ecosystem which limits the distribution or numbers of a population

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2
Q

Why is the a limiting factor important in ecology?

A

It defines optimal survival conditions according to its effect on a species when in deficiency or excess

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3
Q

Can limiting factors be both biotic and abiotic?

A

Yes, Si, oui, Da, Ja,

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4
Q

Biotic Limiting factors in an ecosystem.

A

. Intraspecific (within species)
. Interspecific (between species

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5
Q

Abiotic Limiting Factors in an ecosystem

A

-Environmental Conditions

.Light
.Temperature
.Salinity
.Rainfall
.Wind velocity
.Soil pH

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6
Q

Who Proposed the Law of Tolerance?

A

Victor Ernest Shelford in 1911

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7
Q

What is the Law of Tolerance in Ecology?

A

According to the law of tolerance populations have optimal survival conditions within critical minimal and maximal thresholds.

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8
Q

What happens to a population if it is introduced to extremes of its limiting factor beyond its tolerance threshold?

A

reates of survival begin to drop.

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9
Q

The distribution of a species in response to a limiting factor can be represented as a bell curve, define the 3 regions of the bell curve accordingly.

A

-The central portion is the optimal zone, where conditions favour maximal reproductive success and survivability
-The tails are zones of stress, where organisms can survive but with reduced reproductive success.
-The ends are zones of intolerance, outermost regions where organisms cannot survive (extremes of limiting factor)

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10
Q

Example of a distribution of an animal due to tolerance and zones of stress.

A

-Coral has an mutualistic relation with zooxanthellae which sits on its surface and prove the coral with nutrition
-The algae cannot survive <18 degrees and leaves the coral in >35 degrees.
-Therefore corals has an optimal growth range in 20-30 degrees water.
-This correlates to corals occupying regions near the equator.

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11
Q

Example of a plant distribution due to tolerance and zones of stress

A

-Plant growth is affected by salinity
=Salt tolerant plants are Halophytes (could be stressed in fresh water)
=non tolerant are Glycophytes (damaged in high salinity)
-Understanding salt tolerance for different plant species is therefore critically to effective crop farming,

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12
Q

What is an ecological niche?

A

Describes the functional position and role of an organism within its environment (all physical and biological conditions which determine survival and reproduction)

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13
Q

What is in an Ecological Niche?

A

-Habitat
-Activity patterns (active time)
-Resource obtained from the environment ( food, territorial boundaries)
-Interspecies interactions (predator, prey, competition)

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14
Q

What happens if two species share identical niche?

A

Competition for available space and resources

-Fitness of one being lowered by the presence of the other
-inevitably, the less well adapted species will eventually be eliminated from the niche

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15
Q

What does interspecific competition within a shared niche trigger?

A

Competitive Exclusion: One species uses the resources more efficiently, driving the other to extinction.

Resource Partitioning: Both species alter their use of the habitat to divide resources between them (niche separation)

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16
Q

What is the Fundamental Niche

A

Is the potential mode of existence, given the adaptations of the species. It refers to the broadest range of habitats it can occupy and roles it can fufil

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17
Q

What is the Realized Niche

A

Actual mode of existence, which results from the combination of its adaptations and competition with other species.

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18
Q

Example of Fundamental vs Realized Niche

A

In a rocky shore environment Chthalamus barnacle can potential occupy the entire rocky shore. However in only occupies the area where the Semibalanus barnacle is absent.

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19
Q

How can interactions between species be classified?

A

By their effet on the organism involved

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20
Q

What is herbivory?

A

Act of eating only plant matter (primary consumers)

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21
Q

Different feeding strategies of Harbivores

A

Mucivores- feed on sap
Granivores- feed on seeds

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22
Q

Example of a harmful herbivore

A

Beetle may feed voraciously on leaves, causing crop failure

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23
Q

Example of a Beneficial Herbivore

A

Fruit-eating animals (frugivores) spread the seeds from a fruit in their faeces, promoting seed dispersal

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24
Q

What is Predation

A

One organism hunts and feeds on another organism

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25
Q

If the prey population drops, what happens to the predator population?

A

also drop

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26
Q

What is Symbiotic relation?

A

close and persistent interaction between two species, could be for survival or advantage without being necessary.
Symbiotic relationships can be beneficial to either one or both organisms in the partner ship

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27
Q

What is Mutualism?

A

Describes the ongoing interaction between two species whereby both species benefit from the interaction

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28
Q

example of mutualism

A

Zooxanthellae have a surface to sit and photosynthesize, and the coral receives nutrients.

Honey bees get nectar, and the flower gets its pollen distributed.

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29
Q

What is Commensalism

A

Describes an ongoing interaction between two species whereby one benefits and the other is unaffected

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30
Q

Examples of Commensalism

A

Decorator crabs remove small fragments of tissue from sea sponges and uses them as camouflage

Remora attach to the underside of sharks to feed off uneaten food scraps

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31
Q

What is parasitism

A

Describes an ongoing interaction between two species whereby one species benefits at the other’s expense

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32
Q

Examples of parasitism

A

Ticks feed off human blood & Leaches

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33
Q

Outline reef building

A

-Corals are colonial organisms made up of single polyps that are connected by a layer of tissue
-The Zooxanthellae algae live within the cells of the coral’s endodermis
-The coral provides the algae with a protective environment and a source of inorganic compound
-Coral polyps secrete calcium carbonate to build a stony skeleton which encases the polyps and algae
-Coral polyps also recycle the waste products of the algae and supplies the zooxanthellae with carbon dioxide
-The algae supply the coral with oxygen, glucose and other organic molecules
-The algae also help the coral to remove necessary waste products

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34
Q

Outline coral bleaching

A

The zooxanthellae within the polyp endodermis gives the coral its vibrant pigmentation
-When there is a large-scale loss of zooxanthellae from the coral (environmental stress) bleaching occurs.
-Without the algae, the corals will starve and die.

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35
Q

Conditions that can cause coral bleaching

A

-Changes in light availability (sedimentation may dilute water)
-Temperature increases (temp above 30)
-Ocean acidification (CO2 concentration in the ocean can lower pH)

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36
Q

What is a keystone species?

A

A species that has a disproportionately large impact on the environment relative to its presence

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37
Q

How do Keystone species affect the ecosystem?

A

-Predators: They can exert pressure on lower trophic levels to prevent them from monopolizing certain resources
-Mutualism:They can support the life cycle of a variety of species within a community (pollinator)
-Engineers: Shape the environment in ways that let other species thrive.

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38
Q

Examples of a Predator Keystone species

A

Sea Stars: prey on urchins and mussels-preventing them from overpopulating

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39
Q

Examples of Mutualism Keystone species

A

Honey bees pollinate a wide variety of plants-ensuring the continuation of the plant life cycle

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40
Q

Examples of an Engineer Keystone Species

A

Beaver build dams that transform the environment in a manner that allows certain other species to thrive

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41
Q

What is a trophic level?

A

The position an organism occupies in a feeding sequence

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42
Q

What trophic level does Producers occupy?

A

1st

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43
Q

What trophic levels do Primary consumers occupy?

A

2nd

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44
Q

What is a food chain?

A

a chain of feeding relationships between species

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45
Q

Is it possible for a species to occupy different trophic levels in a food chain?

A

yes

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46
Q

what is a food web?

A

A diagram of multiple food chains feeding on each other

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47
Q

What does food webs show that are more accurate than an food chain?

A
  • Organism can have more than one predation
  • Organism can have more than one food source
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48
Q

what is ecological production/productivity?

A

The biomass generation rate in an ecosystem

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49
Q

What is the unit of Ecological production

A

kg /m^2 day

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50
Q

What is biomass?

A

The total dry weight of an organism or ecosystems

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51
Q

State the factors that dictates % energy converted into biomass

A
  • Energy lost as inedible materials (bones, teeth, hair)
  • Energy lost via execration of undigested materials
  • Energy lost as heat from cellular respiration
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52
Q

What is primary production?

A

The production of chemical energy by producers

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53
Q

What is the main source of energy for primary production

A

Sunlight

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54
Q

Categories of primary productions

A
  • GPP
  • NPP
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55
Q

Define (GPP) Gros primary production

A

The amount of energy as biomass a producer creates in a given length of time

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56
Q

Define (NPP) Net Primary production

A

The amount of energy left after energy consumed by cell respiration from GPP

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57
Q

What is secondary production?

A

The generation of biomass by heterotrophic/consumer organisms

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58
Q

How does biomass generation work in secondary production

A

By feeding on different animals in trophic levels

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59
Q

what is the feed conversion ratio?

A

The efficiency of how much an animal is fed and how much weight they gain

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60
Q

Equation of feed conversion ratio

A

(FCR) = mass of feed ÷ mass of desired output

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61
Q

How can feed conversion ratio be minimized?

A
  • Restricting animal movement (reduce energy loss)
  • Optimizing feeding so food is digested more efficiently
  • Slaughtering animals at an young age
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62
Q

Traits of a closed ecosystem?

A

exchanges energy but not matter

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63
Q

Traits of an open ecosystem?

A

Exchanges both matter and energy

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64
Q

What is a ecosystem?

A

The interaction between biotic and abiotic factors in an environment

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65
Q

What is a biome?

A

A geographical area with a particular climate and contains a specific community of plants and animals

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66
Q

Main factors affecting the establishment of certain biomes?

A
  • Temperature
  • Rainfall
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67
Q

What factors affect Temperature and Rainfall?

A
  • Longitude Latitude
  • Proximity to ocean
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68
Q

List some biomes

A
  • Tropical Rainforests
  • Taiga
  • Deserts
    -Tundra
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69
Q

Climograph of a Dessert biome

A
  • Low rainfall
  • High temperatures
70
Q

Climograph of a rainforest

A
  • High temperatures
  • High Rainfall
71
Q

Climograph of a Taiga

A
  • Low rainfall
  • Low temperatures
72
Q

How would the size of Energy pyramids differ by biomes

A

Tropical rainforest > Taiga > desert

73
Q

What in the world is a Gersmehl diagram?

A

Shows the difference in nutrient flow and storage between different types of ecosystems

74
Q

Gersmehl Diagram of an tropical Rainforest

A
  • Most nutrients are stored as biomass
  • Fast rate of transfer between stores
75
Q

Germehl Diagram of a Taiga

A
  • Most nutrients are stored as litter
  • There is little nutrient gain from precipitation or weathering due to low levels of rainfall
  • There is little nutrient loss via leaching
76
Q

Germehl Diagram of a Desert

A
  • Most nutrients are stored in the soil
  • There is little nutrient gain from precipitation and little loss via runoff
  • the amount of weathering and leaching is negligible
77
Q

Outline the effects of natural Disturbance

A

May give rise to secondary succession (where one ecosystem replaces another)
- Secondary succession occurs on existing soil
- This upheaval results in the removal of existing biota and a new ecosystem emerges from the ashes of the old
- Since the soil is already developed dominance is achieved by the fastest growing plants

78
Q

Outline how humans interfere with nutrient cycle through deforstation

A
  • Less trees less evaporation less moisture less rain
  • Less trees less litter less nutrient in the soil
  • Less chemical weathering of rocks due to less water in soil and rapid loss of nutrients through leaching
  • Soil becomes acidic and release Al & Fe to form an infertile soil
  • Infertile land reduces vegetative growth reducing biodiversity
  • Alters the distribution of plant species by removing te canopy and increasing light exposure
  • No canopy also results in loss of nutrients from soil via runoff
79
Q

List some environmental disturbances

A
  • Forest fire
  • Roads and cities
  • Dams and artificial rivers and creeks
80
Q

How can effects of environmental disturbances be measured?

A
  • Population density
  • species diversity and richness
  • Presence of indicator species
  • Canopy coverage
  • Biomass
  • Soil erosion

(BCPPSS) (British Columbia PP Schutz Staffel )

81
Q

What is an Endemic species?

A

Species that is native to a geographic region

82
Q

What is an Alien species?

A

Species that have been transferred from their natural habitat to a new environment

83
Q

What is an Invasive species?

A

An alien species that threaten the biodiversity of the ecosystem by displacing native species.

84
Q

What is the competitive exclusion principle?

A

That two species cannot occupy the same niches within a community

85
Q

List the advantages that invasive species have over endemic species

A
  • Typically can occupy a wider area than endemic species
  • They will often have faster reproduction rates
  • They commonly lack a predator
  • They may posses some features better suited for the new environment
86
Q

Cane Toad Case study

A
  • Cane toads were added to australia to control the spread of the sugar cane beetle
  • It failed
  • Reproduced rapidly without predictors
  • Has a wide diet takes food away from other animals
  • It secretes toxic chemical poisoning native predators
  • Transmitted disease to native species
87
Q

Wild Rabbits Case study

A
  • Introduced to Australia for recreational hunting
  • Population exploded
  • Killed native plant species
  • Loss of native plant has exposed topsoil for erosion
  • Rabbit proof fences built to contain them
  • Hunting and poison utilized
  • Biological warfare engaged with rabbit-borne diseases
88
Q

Three main methods of Population control

A
  • Physical
  • Chemical
  • Biological
89
Q

Outline Physical control of populations

A
  • Involves removal of invasive species via mechanical or manual means
  • Installation of barriers or removal of habitats
  • Hunting, trapping, genocide
  • Physical methods are not species specific and usually affect endemic life as well
90
Q

Outline Chemical control of populations

A
  • Involves the use of chemical agents
  • Herbicides, pesticides
  • Might be indiscriminate and harm local wildlife
  • Costly
  • Might become more pronounced via biomagnification
91
Q

Outline Biological Control of populations

A
  • Involves using living organisms to control an invasive species
  • Predation
  • Biological agents must be assessed for loyalty and not defect into an invasive
92
Q

Vidalia Beetle Biocontrol case study

A
  • Cushion scale is invasive to California
  • Feds on citrus plants and screwed Cali citrus industry
  • Vidalia beetle a predator of Cushion scale recruited from Australia for Biological control
93
Q

What is biomagnification?

A

The process via which chemical substances become more concentrated at each trophic level

94
Q

What is bioaccumulation?

A

When chemical substances build up in tissues of a single oraganism

95
Q

Why does biomagnification occur?

A

Since animals at higher trophic levels must consume more contaminated animals to meet energy requirements

96
Q

Arguments for DDT spraying

A
  • Affordable and effective against diseases such as malaria
  • Where DDT have been discontinued malaria deaths increased
  • Health cost for malaria treatment is reduced when DDT is implemented
  • Alternative not cost effective or successful
97
Q

Arguments against DDT spraying

A
  • Cause Cancer, birth defects etc
  • Persists in environments for too long
  • Biomagnified and has negative effects on ecosystems
98
Q

What is microplastic?

A

Small invisible plastic

99
Q

What is Macroplastic

A

Large visible plastic

100
Q

Consequences of Micro and Macro plastics?

A
  • Mistaken as food for by marine animals
  • Biomagnification and bioaccumulation of persistent organic pollutant in marine life
  • damage stomach of animals
101
Q

Laysan Albatross Case study

A
  • Nests in the North Pacific gyre where large amounts of plastic is found
  • Feeding tactic causes them to ingest large amounts of plastic
  • Chicks can’t throw the plastic up and accumulates in heir stomach
  • Mortality rate of Albatross chicks is very high
102
Q

Sea Turtles Case Study

A
  • Sea turtles mistake plastic bags for jellyfish
  • Ingestion of plastic can be fatal
  • Plastic bag can ensnare the turtle restricting movement and development
  • Estimated 100, 000 sea turtles and other marine life are harmed by plastic bag each year.
103
Q

What is an indicator species?

A

Species that are sensitive to environmental conditions and therefore have a small range of tolerance

104
Q

What does growth or reduction in the populations of indicator species signify ?

A

Changes in environment.
- useful for monitoring change

105
Q

Some factors indicator species are sensitive to?

A
  • lichen and Mosses are susceptible to airborne pollutants dissolved in water
  • tubifex worms are sensitive to concentrations of heavy metals
  • mayfly larva and others are sensitive to dissolved oxygen levels in water
106
Q

What does a high biotic index mean?

A

Presence of many sensitive species which means the environmental is unpolluted >10

107
Q

What does a low biotic index mean?

A

lack of many sensitive species which means the environmental is polluted 0-2

108
Q

What is Biodiversity?

A

The variety and variability of all living organisms within a given ecological area

109
Q

Main components of Biodiversity

A
  • Species Richness
  • Species evenness
110
Q

What is species richness?

A
  • Number of different species present in an area
111
Q

What is species evenness?

A
  • Abundance of the different species in an area
112
Q

Look up Simpsons reciprocal index equation (skill)

A

you have to pay to include pics :(

113
Q

What does a High Simpsons Index tell?

A
  • A stable site with many different niches and low competition ( high rich and evenness)
114
Q

What does a Low Simpsons index tell?

A
  • A site with few potential niches where only a few species dominate
115
Q

Biodiversity is proportional to what?

A

Island size

116
Q

Factors affecting biodiversity

A
  • Larger habitat promote more biodiversity
  • Ecology at the edges is different from centre (sun & wind)
117
Q

What is the edge effect?

A

edge effects are changes in population or community structures that occur at the boundary of two or more habitats

118
Q

Features of edges

A
  • tend to have more competition than central regions
  • Tend to have greater biodiversity
119
Q

How does larger Island size affect biodiversity?

A
  • support greater range of habitats
  • Sustain more populations
  • more productivity at each trophic levels, stable food chains
120
Q

What is conservation?

A
  • The protection and maintenance of natural resources
121
Q

Types of conservation

A
  • In situ (on site)
  • ex situ (off site)
122
Q

Examples of In situ conservation

A
  • National park
  • Reserves
123
Q

Active management of In Situ conservation

A
  • Ecological monitoring of species may be required to ensure viable population levels are maintained
  • Interventions may be required to stop invasive species
  • Legislation may be necessary to ensure adequate funding
124
Q

Advantages of In Situ conservation

A
  • Species lives in an environment they are adapted to and naturally occupy
  • maintains animal’s normal behavior
  • Prevents natural habitat’s eventual loss and ensures it remains available for other endangered species
  • place to return animals from breeding programs
  • Scientific study and developing public awareness
125
Q

when are Ex Situ conservation helpful?

A
  • Critically endangered species when urgent intervention is required
126
Q

Advantages of Ex Situ Conservation

A
  • Greater control of essential conditions (climate, dietary, veterinary)
  • ## Improve chances of successful breeding
127
Q

Disadvantages of Ex Situ Conserveation

A
  • does not prevent the potential destruction of their natural habitat
  • Less likely to be successful when reintroduced to the wild
  • Increasing inbreeding
128
Q

Examples of Ex Situ Conservation

A
  • Zoos
  • Botanical gardens
  • Seed banks
129
Q

Captive breeding Rhino case study

A
  • The Indian rhinoceros is a endangered species with only approximately 3,500 rhinoceros living in the wild
  • This number was as low as 2,000 in the early 1990s, but has increased due to successful captive breeding programs
  • In addition to habitat loss, the Indian rhinoceros is threatened by poachers (their horn is considered potent in some cultures)
  • It is listed as vulnerable on the IUCN red list and the majority of the species is situated in Indian protected areas (reserves)
130
Q

Captive breeding Mountain Chicken frog case study

A
  • The mountain chicken frog is a species of frog native to the Carribean islands of Dominica and Montserrat
  • The population of this frog has declined 81% in the last ten years due to the fungal disease chytridiomycosis
  • The mountain chicken frog is also threatened by human consumption (it is a local delicacy said to taste like chicken)
  • It is now considered to be critically endangered with fewer than 8,000 individuals estimated to be existing in the wild
  • The frog has been artificially bred in laboratories in England prior to being reintroduced into the wild
131
Q

What is Natality?

A

Increases to population size due to reproduction

132
Q

What is Immigration?

A
  • Increases to population size from external populations
133
Q

What is Mortality?

A
  • Decrease in populations due to Death
134
Q

What is Emigration?

A
  • Decreases to population size due to loss to external populations
135
Q

Equation of population size

A

Population Size = (Immigration + Natality) – (Mortality + Emigration)

136
Q

What indicates a good Population estimate?

A
  • Random selection of areas
  • More samples more accurate data
137
Q

A sampling technique for non-motile species

A

Quadrats

138
Q

A sampling technique for motile species

A

Capture-mark-release-recapture method

139
Q

Lincoln index

A

(n1 × n2) ÷ n3
- n1 = First capture
- n2 = Second capture
- n3= recapture of n1

140
Q

Assumption of the lincoln index

A
  • Sampling is random
  • marked individuals are randomly distributed after release
  • marking cannot affect mortality or natality
141
Q

Two types of growth patterns

A
  • Exponential [Ideal unlimited environment]
  • Logistic growth (s curve) [environmental pressure slow rate of growth]
142
Q

Features of Exponential growth

A
  • Resources unlimited
  • no competition
  • initial growth is slow
  • population increases exponentially
  • max growth rate is the Biotic potential
  • seen in small or newly colonized species
143
Q

Features of Logistic growth

A
  • population has a finite carrying capacity (# of species the environment can support)
  • has environmental resistance
  • growth plateaus at carrying capacity
  • seen in stable population in a fixed geographical area
144
Q

Density dependent population factors

A

(panda)
- Predators
- Availability of resources
- Nutrient supply
- Disease
- Accumulation of wastes

145
Q

Density independent population factors

A

(PAW)
- Phenomena (natural disaster)
- Abiotic factors
- Weather conditions

146
Q

Phases of Sigmund curve

A
  • Exponential Growth phase (slow initial but then rapid increase in pop)
  • Transitional phase (resources limited, survival of the fittest)
  • Plateau phase (natality = mortality)
147
Q

Benefits of using simple organism like yeast and duckweed to model population growth

A
  • Easily populates small container and easy to store
  • nutritional requirements are low, makin git inexpensive
  • reproduce very rapidly, faster results
148
Q

What happens to the growth model of a yeast and duckweed experiment

A
  • follows the regular sigmond pattern
  • but has an death phase after plateu, since its a closed system and waste builds up.
149
Q

Top down control of populations

A
  • Pressures applied by a higher trophic level
  • the top predator limits the rate of population growth of its prey
  • results in oscillating trophic cascade (-fox, +frog, -snails, +plants)

negative = decreasing
positive = increasing

150
Q

Bottom up control of populations

A
  • limits the availability of resources at lower trophic levels
  • lack of resources suppresses abundance of organisms at higher trophic levels
  • pop drops at higher levels
  • humans can cause this
151
Q

What is eutrophication?

A

Sudden enrichment of nutrients in the water due to run off

152
Q

Effects of Algae bloom

A
  • Algae will block sunlight for phytoplankton and seaweeds
  • low sunlight will cause algae to respire reducing O2 in water
  • when algae die increase in bacterial decomposers will further reduce O2 in water
  • with low O2 and light aquatic animals will die
153
Q

Bottom up control of algae

A
  • Limit supply of N and P in the water
  • Reduce fertilizer use
  • Expensive and difficult to police
154
Q

Top down control of alge

A
  • introducing fish eating fish into the system
  • kills Zooplanktons predator
  • Increased amounts of zooplanktons eat algae
  • Risky could cause unintended consequences
155
Q

What is a sustainable yield?

A
  • is the amount of a natural resource that can be taken from an ecosystem without reducing the base stock
156
Q

Maximum sustainable yield (MSY)

A
  • is the highest proportion of fish that can be removed without jeopardizing this max yield in the future
  • Optimal balance between natality to mortality and harvesting
  • MSY should be half the carrying capacity of the species
  • Fishing over MSY screws future yields, not enough fish (base stock) to replenish
157
Q

Outline Methods of determining MSY

A
  • Capture mark release recapture
    • Lincoln index method
    • Fish stunned and captured via electro shocking
    • Not viable in ocean only in rivers and lakes
  • Echo sounders
    • Sonar to identify the size of schools of fish
    • non invasive but only effective in shoals
  • Analyzing fish catch data (math)
    • Fish catches data used to estimate pop sizes
    • Accuracy relies on fishing community
    • Might require international help in international waters
    • if fish people don’t comply to regulations than data is biased
158
Q

Outline sustainable Fishing practice

A
  1. Population size
    - MSY should be half of carrying cap
    - Limit total allowable catch sizes and registering all fishing boats to control
    - Certain regions could be banned for fishing as conservation
  2. Age
    - If pop growing, then more young fish
    - If pop is declining then more old fish
    - mesh sizes restrictions can omit young smaller fish
    - use fish farms so not kill younglings
  3. Reproductive status
    - let fish do fish love
    - Regulate fishing seasons
    - Exclusion zones over breeding areas
159
Q

Draw me a diagram of the nitrogen cycle

A

slkdfj

160
Q

Outline N fixation

A

N2 must be converted to NH3
- catalyzed by nitrogenase, produced by nitrogen fixing bacteria in the soil
- Azotobacter is found living freely in soil
- Rhizobium forms mutualistic bond with roots of legumes, supplies ammonia for carbohydrates
- Ammonia becomes Ammonium when in water, can be used by plants

161
Q

Outline Ammonification

A

Ammonia can form when organic things are broken down by decomposers
- Saprotrophs will decompose dead things to produce ammonia and ammonium
- process called ammonification, the released ammonium can go into soil for plants

162
Q

Outline Nitrification

A

Conversion of ammonium ions into nitrates and nitrites by bacteria in soil
- Nitroso monas converts ammonium ions into nitrites, Nitrobacter can convert the nitrites into nitrates
- Require oxygen, soil must be aerated
- Nitrites and nitrates are easier for plants to use

163
Q

Outline Denitrification

A

converts nitrites to N2
- by denitrifying bacteria in the absence of O2
- Nitrates can be used instead of O2 in cell respiration producing Nitrogen gas
- Occurs in O2 poor conditions

164
Q

What is waterlogging?

A

When water is unable to drain away from soil

165
Q

How does Waterlogging impact the N cycle

A
  • Lose nitrates and nitrites via denitrification
  • creates poor oxygen conditions perfect for denitrification bacteria
  • ## With leaching, as water drains downwards it takes minerals (nitrates and Nitrites) from soil with it
166
Q

Example of a plant adapting to low nitrogen (waterlogged) environement

A
  • Venus fly trap traps insects by baiting them with nectar
  • Then enzymes digest the insect absorbing nutrients
  • Gets N2 from feeding on insects
167
Q

Outline P cycle

A
  • certain rocks have Phosphate, released via chemical weathering in soil and water
  • Organisms need it for ATP, nucleic acids, membranes etc
  • Phosphates go back to soil after decomposition
  • No gas component
  • Rate of turnover (release) is slower than N cycle
  • Replacement is also slow
168
Q

How can Phosphate be added to and removed from the cycle?

A
  • mining phosphates and making Fertilizers for plants
  • when harvested phosphate lost as part of biomass
169
Q

Horrors of Phosphate Fertilizer

A
  • Phosphate cycle slow
  • Phosphate are being removed too fast
  • Might not have phosphate based fertilizer in the future
  • no alternative so far
  • might limit crop yield in future
170
Q

what is soil made of?

A
  • organic matter
  • Rock
    -Mineral particles
    (proportions of these and pH determine soil type)
171
Q

How to figure out nutrient content of a soil

A
  • Chemical produce different colour when testing for N, P, K

BIO (9 decks)

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