Soil Biota Flashcards
(61 cards)
What is soil biota?
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.
What constitutes the fourth and higher trophic level of the soil food web?
Higher level predators
What are the three community characteristics?
- High Diversity
- High abundance
- High biomass
What is soil habitat?
The totality of living organisms inhabiting soil including, plants animals and microorganisms and their abiotic environment.
Where are microorganisms located in soil?
Usually found near root surfaces, in dead roots, on soil particles or amongst aggregates of soil particles.
What kind of soil has highest bacteria population?
Clay soils because these soils have micropores for the bacteria to reside.
What are the 5 classifications of soil organisms?
- Microbes
- Microfauna
- Mesofauna
- Macrofauna
- Megafauna
What kind of an organism is bacteria?
It is a microorganism.
What is the cell wall of bacteria made up of?
Peptidoglycan
What is the cell wall of archaea made up of?
Phytanyl
What is different about eukarya compared to archaea and bacteria?
Eukaryotes do not have a cell wall and they have a membrane-bound nucleus.
What are the 4 functional groups of bacteria?
- Decomposers
- Mutulists
- Lithotrophs (chemoautotrophs)
- Pathogens
What are photoautotrophs?
Energy source is light. Carbon source is CO2. Ex: Plants, algae, cyanobacteria
What are chemoautotrophs?
The energy source is inorganic chemicals. Carbon source is CO2. Ex: Sulfolobus
What are photoheterotrophs?
Energy source is light. Carbon source is organic compounds . Ex: extremophiles
What are chemoheterotrophs?
Energy source is inorganic chemicals. Carbon source is organic compounds.
What kind of a bacteria is cyanobacteria?
It is gram negative.
What is an example of gram-positive bacteria?
Bacillus anthracis
What is the difference between gram-positive and gram-negative bacteria?
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.
What are some examples of gram-negative bacteria?
Pseudomonas fluorescens, and Cyanobacteria
What are the six positive effects of bacteria in soil?
- Improves soil structure and aggregation
- Biochemical nutrient cycles
- Promotes plant growth
- Enhance natural succession: improves quality of soil so new plants can survive
- Soil health indicator.
What are the 4 negative effects of bacteria in soil?
- Pathogenic bacteria can result in poor crop health
- Pathogenic bacteria can cause diseases in humans.
- some bacteria can decrease soil health
- By-products from bacteria can change soil properties.
What are some characteristics of soil actinomycetes?
- Unicellular
- Transition group between bacteria and fungi.
- Degrades organic compounds
- Optimal growth at alkaline ph
- Gram positive
how is archaea different from bacteria?
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.