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SOIL 4400 > Soil Biota > Flashcards

Soil Biota Flashcards

1
Q

What is soil biota?

A

Soil biota consists of the micro-organisms, soil animals, and plants in the soil. They make the soil food webs and contribute energy and nutrient flow in the soil system.

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2
Q

What constitutes the first trophic level of the soil food web?

A

Photo synthesizers.

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3
Q

What constitutes the second trophic level of the soil food web?

A

Decomposing mutualists
Pathogen
Parasites
Root-feeders

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4
Q

What constitutes the third trophic level of the soil food web?

A

Shredders
Predators
Grazers

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5
Q

What constitutes the fourth and higher trophic level of the soil food web?

A

Higher level predators

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6
Q

What are the three community characteristics?

A
  1. High Diversity
  2. High abundance
  3. High biomass
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7
Q

What is soil habitat?

A

The totality of living organisms inhabiting soil including, plants animals and microorganisms and their abiotic environment.

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8
Q

Where are microorganisms located in soil?

A

Usually found near root surfaces, in dead roots, on soil particles or amongst aggregates of soil particles.

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9
Q

What kind of soil has highest bacteria population?

A

Clay soils because these soils have micropores for the bacteria to reside.

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10
Q

What are the 5 classifications of soil organisms?

A
  1. Microbes
  2. Microfauna
  3. Mesofauna
  4. Macrofauna
  5. Megafauna
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11
Q

What kind of an organism is bacteria?

A

It is a microorganism.

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12
Q

What is the cell wall of bacteria made up of?

A

Peptidoglycan

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13
Q

What is the cell wall of archaea made up of?

A

Phytanyl

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14
Q

What is different about eukarya compared to archaea and bacteria?

A

Eukaryotes do not have a cell wall and they have a membrane-bound nucleus.

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15
Q

What are the 4 functional groups of bacteria?

A
  1. Decomposers
  2. Mutulists
  3. Lithotrophs (chemoautotrophs)
  4. Pathogens
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16
Q

What are photoautotrophs?

A

Energy source is light. Carbon source is CO2. Ex: Plants, algae, cyanobacteria

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17
Q

What are chemoautotrophs?

A

The energy source is inorganic chemicals. Carbon source is CO2. Ex: Sulfolobus

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18
Q

What are photoheterotrophs?

A

Energy source is light. Carbon source is organic compounds . Ex: extremophiles

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19
Q

What are chemoheterotrophs?

A

Energy source is inorganic chemicals. Carbon source is organic compounds.

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20
Q

What kind of a bacteria is cyanobacteria?

A

It is gram negative.

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21
Q

What is an example of gram-positive bacteria?

A

Bacillus anthracis

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21
Q

What is the difference between gram-positive and gram-negative bacteria?

A

Gram-positive bacteria has a thicker peptidoglycan layer with no outer membrane and it stains the cell violet.

Gram-negative bacteria has a thin peptidoglycan layer with an outer membrane that does not stain with crystal violet.

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22
Q

What are some examples of gram-negative bacteria?

A

Pseudomonas fluorescens, and Cyanobacteria

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23
Q

What are the six positive effects of bacteria in soil?

A
  1. Improves soil structure and aggregation
  2. Biochemical nutrient cycles
  3. Promotes plant growth
  4. Enhance natural succession: improves quality of soil so new plants can survive
  5. Soil health indicator.
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24
Q

What are the 4 negative effects of bacteria in soil?

A
  1. Pathogenic bacteria can result in poor crop health
  2. Pathogenic bacteria can cause diseases in humans.
  3. some bacteria can decrease soil health
  4. By-products from bacteria can change soil properties.
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25
Q

What are some characteristics of soil actinomycetes?

A
  1. Unicellular
  2. Transition group between bacteria and fungi.
  3. Degrades organic compounds
  4. Optimal growth at alkaline ph
  5. Gram positive
26
Q

how is archaea different from bacteria?

A

Archaea does not contain peptidoglycan and the cell membrane uses ether linked lipids compared to ester linked lipids in bacteria. They are able to survive extreme conditions.

27
Q

What are some functions of archaea in he soil?

A

Recycle carbon, nitrogen and sulfur through their various habitats. Involved in plant stress response.

28
Q

Is archaea is the soil shown to be beneficial or harmful to the human health?

A

Beneficial

29
Q

What are some characteristics of fungi?

A
  1. Eukaryotes
  2. Multicellular or unicellular
  3. Most are aerobic other than yeast.
  4. They can tolerate a wider range of ph compared to bacteria.
30
Q

What are the three functional groups of fungi?

A

Decomposers, Mutualists and pathogens.

31
Q

What are the three morphological groups of fungi?

A

1.Dimorphism
2. single celled: Yeast
3. Multicellular: Mold

32
Q

What is the main why fungi reproduce?

A

Asexual spores

33
Q

What are the five different groups of fungi divided according to reproductive features?

A
  1. Chytridiomycota: Flagellated spore
  2. Zygomycota: Produces zygospores, sexual spores
  3. Glomeromycota: Form arbuscular mycorrhizae with plants.
  4. Ascomycota: Sexual spores, ascospores borne in an asci.
34
Q

What are some characteristics of Chytridiomycota?

A

Aquatic, chitinous cell walls flagellated zoospores. Most primitive fungi. They can be saprobes or parasites.

35
Q

What are some characteristics of Zygomycota?

A

Mostly terrestrial.
Live in soil or dead plants.
The most common types of bread molds and fruit molds.

36
Q

What are some characteristics of Glomeromycota?

A

Symbiotes that form intercellular association with plant roots.
Need host plant to survive.
Present in about 80% vascular plants.
Aseptate hyphae.
Asexual.

37
Q

What are some characteristics of Ascomycota?

A

Sexual spores are produced in a sac like structure called an ascus.
Cell wall is made up of mostly chitin.
Can be parasitic for plants and humans.
Found in human mouth, cheese, the soil.

38
Q

What are some characteristics of Basidiomycota?

A

Obtain nutrients from dead/decaying matter.
Can be unicellular or multicellular.
Sexual or Asexual reproduction.
Terrestrial and aquatic.
Can be plant pathogen (rusts) or mushrooms.

39
Q

What are the 5 main functions of fungi in the soil?

A
  1. Decomposers.
  2. Cycling and transport of nutrients.
  3. Protects plants against pathogenic microorganisms.
  4. Aids in the production of bread, wine, and beer.
  5. Used as food. (Mushroom)
40
Q

What are some characteristics of protists?

A
  1. Unicellular eukaryotes with no cell wall.
  2. Larger than bacteria.
  3. Means ‘first animal’
  4. Heterotrophs and ingest bacteria, algae and small protozoa.
  5. most species are harmless and live on land and water.
  6. Sexual and asexual reproduction.
    7 Living and dead plant roots influence the number of protozoa in the soil.
  7. Cultivated and clay soils mostly have flagellated protists.
41
Q

What are the three groups of protozoa found in coil?

A

Flagellated, Ciliates and Amoeba.

42
Q

What are the largest protozoa in the soil?

A

Ciliates. They eat the other 2 protozoa and move with the help of cilia.

43
Q

How do amoeba move?

A

With the help of pseudopods.

44
Q

What are the two kinds of amoeba?

A

Testate amoeba ( with shell-like covering)
Naked amoeba ( without a covering)

45
Q

How do flagellated amoeba move?

A

With the help of their flagella. They are the smallest of the protists.

46
Q

What are the 4 main roles of protozoa in the soil?

A
  1. Mineralizing nutrients as C:N ratio is much higher in protozoa than in bacteria.
  2. Regulates bacteria population.
  3. Important food source for nematodes.
  4. Suppress disease by competing with or feeding on pathogens.
47
Q

What are nematodes?

A

They are non-segmented worms.

48
Q

What are the different types of nematodes based on their diet?

A
  1. Bacterial feeders
  2. Fungal feeders
  3. Predatory nematodes
  4. Omnivores.
49
Q

Where can nematodes be found?

A

In the Rhizosphere where the plant roots grow.
Near their prey group.
More abundant in coarser texture soil.

50
Q

What are the 5 roles of the nematodes?

A
  1. Nutrient cycling.
  2. Grazing
  3. Dispersal of microbes
  4. Food source
  5. Disease suppression and development.
51
Q

What does a high ratio of bacterial nematodes to fungal nematodes indicate?

A

Nutrient cycling with high levels of nitrogen.

52
Q

What does a high number of omnivorous nematodes indicate?

A

Pollutants in soil.

53
Q

What does a high number of omnivorous and predatory nematodes indicate?

A

Suppression of plant predatory nematodes.

54
Q

What does arthropods mean?

A

Joined legs

55
Q

What is a characteristics of arthropods?

A
  1. Invertebrates
56
Q

What are the 4 feeding groups of arthropods?

A
  1. Shredders: eat bacteria and fungi on dead plant matter.
  2. Predators: Eat insects.
  3. Herbivores: Root feeders
  4. Fungal feeders
57
Q

What are the 6 roles of arthropods?

A
  1. Shred organic material.
  2. Stimulate microbial activity
  3. Mineralize plant nutrients.
  4. Enhance soil aggregation.
  5. Burrow.
  6. Control pests.
58
Q

Where do arthropods live in the soil?

A
  1. Near the surface of the soil.
  2. A square yard of soil can have 500 - 200,000 individual arthropods.
59
Q

What are some characteristics of earthworms?

A
  1. Invertebrates
  2. Hermaphrodites ( Have both sexual organs)
  3. Decompose dead and decomposing organic mater.
  4. 23 families, more than 7000 species.
60
Q

Where can earthworms be found?

A

Temperate soils and many tropical soils.

61
Q

What are the three major groups of earthworms based on feeding and burrowing?

A
  1. Epigeic: surface soil and litter species.
  2. Endogeic: Upper soil species.
  3. Anecic: Deep burrowing species.
62
Q

What are the 6 main functions of soil biota/ soil organic matter?

A
  1. Formation of turnover of SOM.
  2. Nutrient cycling
  3. Promotes plant growth
  4. Disease transmission and prevention.
  5. Pollution degradation
  6. Improvement in soil structure.
63
Q

What is the soil food web?

A

The soil food web is the community of organisms living all or part of their lives in the soil. A food wed diagram shows a series of conversions of energy and nutrients as one organism eats another.

SOIL 4400 (8 decks)

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