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Module 6 > Ecosystems > Flashcards

Ecosystems Flashcards

1
Q

What is an ecosystem

A

All the interacting living organisms & non-living factors in a particular in a particular area - this is a dynamic system, & varies in size too e.g. a rock field, a playing pool, a large tree

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2
Q

What’s a community

A

All populations of all species in a particular habitat

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3
Q

What is a population

A

All the individuals of one slices in a particular habitat

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4
Q

What is a ‘species’

A

Can reproduce to produce fertile offspring

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5
Q

Biotic vs Abiotic factors

A

Biotic = living factors that affect it e.g. competition, predation, disease
Abiotic = non-living factors that affect it e.g. light, pH on soil, temp, water & O2 availability

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6
Q

What is a niche

A

The role of a species in an ecosystem

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7
Q

Types of changes in ecosystems

A

Cyclical (repeat in rhythm e.g. tides)
Directional (e.g. go in 1 direction, lasting life, like erosion)
Erratic/ Unpredictable = no rhythm / direction (natural disasters)

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8
Q

What is a tropic level

A

The stage in food chain
Order = producers -> primary consumers -> secondary consumers -> tertiary consumers -> apex predator

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9
Q

What is biomass

A

The dry mass (without water) of living material in an area / organism
-> we consider this: > mass as water levels can fluctuate within the organism, depending on time of day / year / area

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10
Q

How is biomass measured

A

Using calorimeters:
- collect the sample, kill the organism, put it in the over @ 80° to remove the water by evaporation & stop once a constant mass has been reached

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11
Q

What are the limitations of calorimeters

A
  • can take a long time to fully dehydrate sample
  • precise equipment needed
  • heat energy lost by calorimeter & not efficiently transferred
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12
Q

Land animals vs marine animals unit

A

G/m^2 vs G/m^3

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13
Q

Ecological efficiency formula
(The efficiency with which biomass is transferred between consecutive tropic levels)

A
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14
Q

How can energy be lost in a food chain

A
  • sunlight reflected so not all used in photosynthesis
  • other factors affect photosynthesis rate
  • hear energy from respiration
  • process of excretion & production of waste materials
  • some parts of food not eaten / digested
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15
Q

What is ‘useful energy’

A

Used to build biomass / body growth

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16
Q

How can we make biomass transfer efficiency of consumers

A
  1. Vaccinate animals / provide antibiotic (less energy loss to pathogens)
  2. Restrict animal movement - less e loss via respiration
  3. Harvest @ peak times (animals can’t grow anymore as adults so don’t waste e on them)
  4. Plants planted earlier (longer growing seasons, more light etc)
  5. Maintain nutrient rich soil (crop rotation)
17
Q

Decomposers vs detrivores

A

Decomposers feed on dead organic matter (secrete enzymes, digest externally, absorb matter)
Detrivores different as they digest internally & increase the SA of the matter to inc rate of decomposition

18
Q

Steps in nitrogen cycl

A
  1. Nitrification
  2. Ammonification
  3. Denitrification
  4. Nitrogen fixation
19
Q

What happens in stage 1 (Nitrification)

A

ammonium ions -> nitrite ions -> nitrate ions
(Oxidation, therefore requires oxygen (well aerated soils))

20
Q

Nitrifying bacteria in Nitrification

A

Nitrosomonas
Nitrobacter

21
Q

Nitrosomonas action

A

Ammonium -> nitrite

22
Q

Nitrobacter action

A

Nitrite -> nitrate

23
Q

What happens in Ammonification (stage 2)

A

Carried out by decomposers

Nitrite / nitrate -> ammonium ions -> ammonia

24
Q

Denitrification (stage 3) - what happens

A

Nitrate ions -> nitrogen gas
Anaerobic conditions (as there are water logged soils, so low O2 levels)
Denitrifying bacteria = Pseudomonas

25
Q

What happens in stage 4 nitrogen fixation

A

Atmospheric nitrogen gas + 3H2 (g) -> 2Ammonia
- nitrogen fixing bacteria (Azotobacter & Rhizobium)
Nitrogen needed to make amino acids & nucleic acids

26
Q

Where are azotobacters found

A

Free living

27
Q

Where are rhizobiums found

A

in root nodules

28
Q

Nitrogen cycle diagram

A
29
Q

What is primary succession

A

A newly formed / exposed land with no species present is gradually colonised by an increasing number of species
This causes the biotic components of the eco system to change over time

30
Q

What is a pioneer species

A

The 1st species to colonise the land
-> autotrophic + able to survive harsh environmental conditions

31
Q

What is a climax community

A

When the final species colonises land
-> becomes a dominant species in an ecosystem
- most complex & diverse community the ecosystem can sustain

32
Q

Succession process

A

1) pioneer species begins to grow
2) this species changes abiotic conditions, therefore less hostile
3) pioneer species die and decompose
4) dead organic matter forms deeper & more nutrient rich soil
5) new species able to grow in less harsh conditions
6) new species outcompetes the pioneer species & previous species
7) changes the abiotic conditions so less hostile to next new colonising species, & less suitable for older ones
8) previous species die, soil deeper & more nutrient rich as a result
9) cycle repeats
10) eventually, climax community reached

33
Q

What is deflected succession

A

When human activities prevents /interrupt the process, resulting in a different climax community than what would be from natural succession

34
Q

How can human activities prevent succession & why is this good

A

E.g.
- managed burning, mowing lawns, introducing grazing animals

This can be good as it maintains high plant & animal diversity, which won’t exist if the climax community is reached

35
Q

What is a sere

A

Each level of succession

36
Q

Details about the Masai marai

A
  • savannah in Africa
  • people raise livestock
  • ecotourism projects, where people employ locals to monitor lions, as conservation trusts help locals make money
37
Q

Details about the terai region in Nepal

A

Grassland, & forest, & variety of plants & animals
-> densely populated region therefore highly dependent on natural resources
E.g. fuel, animal feed, human food, medicines
-> conservation chattiest have worked to conserve the forest e.g. protecting against poaches teaching locals forestry skills

38
Q

Peat bogs details

A

Areas of water logged land (incomplete decomposition)
Anaerobic & acidic conditions = decomposed plant matter accumulates and becomes compacted & = PEAT, which builds up to form carbon store
-> this carbon store is exploited & burns as fossil fuels, even tho the peat supports lots of plant species & those in turn support intervertebrae

Module 6 (7 decks)

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