EXAM 3: Chapter 11

Question 1

Detritus

Answer 1

Debris of dead tissues left by plants on the soil surface and within the soil pores

Question 2

Detritivores

Answer 2

A primary consumer whose principal food source is detritus

Question 3

Collembolans

Answer 3

Jumping organisms with “spring tails” that allows them to jump very far

Question 4

Ecological engineers

Answer 4

Animals that majorly alter their physical environment which influences the habitats of other organisms; termites and ants create krotovinas, dung beetles carry animal feces to different places and bury them; earthworms shred and push soil around

Question 5

Protozoa

Answer 5

• Mobile, single-celled creatures that capture and engulf their food
• Most are considered larger than bacteria but do not have true cell walls and are more biologically advanced
• amoebas, ciliates, and flagellates that swim in water-filled pores
• usually active immediately around plant roots

Question 6

Nematodes (different types/roles)

Answer 6

• Plant-parasitic nematodes can infest the roots of plant species with a spearlike, sharp mouth
• ## Predator nematodes feed on animals by invading larvae with hard teeth and a large mouth

Question 7

Actinomycetes

Answer 7

Generally aerobic heterotrophic bacteria in a specific order of Actinobacteria; filamentous and often profusely branched that look similar to fungi but have a different genetic makeup; no nuclear membrane

Question 8

Fungi

Answer 8

Eukaryotic cells with a nuclear membrane and cell walls, more closely related to humans than bacteria is to archaea
- typically absorb small soluble organic molecules like simple sugars or amino acids

Question 9

Algae

Answer 9

Eukaryotic cells with nuclei inside a clear membrane that are equipped with chlorophyll

Question 10

Microbial metabolism

Answer 10

The biochemical degradation by soil organisms

Question 11

Rhizobium

Answer 11

Bacteria that help supply legume plants with N

Question 12

Rhizobacteria

Answer 12

Bacteria adapted to living in the rhizoplane; can offer enhanced nutrient uptake or hormonal stimulation or inhibit root growth and function by noninvasive chemical interactions

Question 13

Rhizosphere

Answer 13

Zone of soil immediate and most influenced by living roots

Question 14

Mucigel

Answer 14

Secretions from root-cap cells and epidermal cells near apical zones that lubricates the root’s movement through the soil improve root-soil contact and stabilize and protect the soil and root systems from certain toxic chemicals

Question 15

Cyanobacteria

Answer 15

(Blue-green algae)

Contains chlorophyll that allows photosynthesis, tolerance to saline and arid environments

Question 16

Mushrooms/Mushroom Fungi

Answer 16

Fungi associated with forest and grassland where moisture and organic residues are ample

Question 17

Hyphae

Answer 17

An extensive network that permeates the underlying soil or organic residue

Question 18

Mycorrhizae (two types)

Answer 18

The beneficial association between certain fungi and the roots of higher plants

• Ectomycorrhiza group, where their hyphae penetrate the roots and develop in the free space around the cells of the cortex but do not penetrate the cortex cell walls (stubby white structures with a Y shape)
• Enodmycorrhiza group (arbuscular mycorrhizae), where their hyphae actually penetrate the cortical root cell walls and form highly branched structures known as arbuscules

Question 19

Actinomycetes antibiotics

Answer 19

Penicillin

Question 20

N-fixing legumes

Answer 20

Soybean

Question 21

Actinomycetes symbiosis with Alder trees

Answer 21

Provide nutrients that can trade with that of other trees