SCSC 301 Exam 2
Chapter 10
Organism Size:
Macrofauna/Flora: Includes mammals, most insects, plants, and mosses.
Mesofauna: Comprises nematodes and protozoa.
Microorganisms: Includes fungi, bacteria, and actinomycetes.
Abundance Depends On:
Quantity & quality of food.
Environmental factors: water, temperature, acidity, salinity, etc.
Predators and competition.
Energy Sources:
Autotrophs: Obtain energy primarily through photosynthesis.
Heterotrophs: Derive energy from carbon consumption.
Causes of Diversity:
Nearly limitless variety of foods.
Wide range of habitat conditions.
Biological Diversity as Indicator of Soil Quality:
Species Diversity:
Indicates organisms are evenly distributed among a large number of species.
Functional Diversity:
Indicates organisms' capacity to utilize a variety of substrates and perform diverse processes.
Earthworms
Segmented worms with burrows and casts
Affect chemical and physical properties of soils
Termites
Ant-like insects that consume wood/residues
Build extensive mounds that influence soil development
Nematodes
Unsegmented worms, often found in sandy soils
Predators of various soil organisms and can act as plant parasites
Protozoa
Single-celled and mobile, thrive in moist, well-drained soils
Feed on bacteria
Plants
Algae
Photosynthesize like plants
Often associated with fungi (lichens) to help colonize rock
Fungi
Highly diverse, thrive in acidic soils
Yeasts: Single-celled, often in anaerobic conditions
Molds: Important in organic matter breakdown
Mushrooms: Prefer high moisture and residue
Mycorrhizae
Special fungi-root associations enhancing nutrient uptake, especially phosphorus
Actinomycetes
Bacteria resembling fungi, involved in organic matter degradation
Known for producing antibiotics and prefer pH of 7-8.5
Bacteria
Extremely diverse with rapid reproduction
Involved in various processes such as nitrification and denitrification.