1.Terrestrial Environment2.Terrestrial Biota and

Biogeographic Regions3.General Structure of

Terrestrial Communities4.Soil Subsystem5.Vegetation Subsystem6.Distribution of Major

Terrestrial Communties , The Biomes

Outline

1.Climatea. Moisture – major

limiting factor on landb. Temprature variations

and extremesc. Air circulation – ready

mixing and constant content of oxygen and carbon dioxide

Terrestrial Environment

2. Substratea. Soil – offers solid

support and source of highly variable nutrients

b. Land – provides geographical barriers to free movement

• Specialized organisms includes plants, arthropods, invertebrates, vertebrates, and others.

• Microorganisms also play vital roles in all ecosystems, such as bacteria, fungi, protozoans, etc.

Terrestrial Biota and Biogeographic

Regions

Biogeographic Regions• Floristic Regions • Faunal Regions

Zoographic RegionAfrotropical=Ethiopian Indo-Malaysian=OrientalNote: Regions Paleartic and Neartic are often united as Holarctic region

General Structure of Terrestrial Communities

• Autrotrophs- green plants usually

dominates the land-obligate autotrophs require

only light and mineral nutrients-algae are photosynthetic

protists that require vitamins or organic nutrients

Classification of Plant Life-forms

• Raunkiær system is a system for categorizing plants using life-form categories, devised by Christen C. Raunkiær.

• The system is based on the place of the plant's growth-point or the renewal bud during seasons , and the corresponding protection provided during unfavorable cold or dry periods.

1. Phanerophytes- aerial plants; renewal buds exposed on upright

shoots

Primary Categories

2. Chamaephytes-surface plants; renewal bud at the surface of the ground

Catharanthus pusillus (Tiny_Periwinkle)

3. Hemicryptophytes- buds at or near the soil surface

Daisies or Bellis Perennis

4. Cryptophytes-earth plants; buds lying beneath the surface of the ground

Geophytes - resting in dry ground, e.g. crocus.

Helophytes - resting in marshy ground, e.g. reed mace, marsh-marigold

Hydrophytes - resting by being submerged under water

6. Aerophytes - obtains moisture and nutrients from the air and rain

5. Therophytes- annual plants which survive the unfavorable season in the form of seeds

7. Epiphytes- air plants; no roots in the soil

Raunkiær system 

a. Vegetation – refers to all the plants in general or the mass of plants growing in a particular place.

b. Flora – refers to a list of taxonomic entities to be found in an area

Phagotrophic (Macro) Consumers

• Primary consumers

– organisms that feed directly on all or parts of plants; includes large herbivores

Saprothrophs or Microconsumers

Decomposer microorganisms4 taxonomic entities

• Fungi – yeasts and molds• Heterothrophic bacteria• Actinomycetes • Soil protozoa – amoeba,

ciliates, flagellates

Soil SubsystemThree size groups

1. Microbiota – includes soil algae, the bacteria, fungi, and protozoa.

2.Mesobiota – detritus-bacterial feeders includes the nematodes, the small oligochaete worms, smaller insect larvae, and microarthropods

3. Macrobiota- includes roots of plants, larger insects, earthworms, and other organisms can be assorted by hand.

Soil Respiration3 methods todetemine total soil metabolism

1. Difference Method – subtracting the energy consumed by above-ground herbivores from net primary production

2. Litter fall method – determining the amount and energy value of the detritus (litter) input into the soil subsystem

3. Direct measurement of CO2

Vegetation Subsystem

• Phytosociology-quantitave study of the structure of vegetation, which aims to describe vegetation, explain its pattern, and classify it in a meaningful way.

• Constancy-percent of plots containing the species

• Fidelity – degree of constriction of a species to a particulat situation

Root/Shoot RatioThe proportion of producer biomass, production or nutrients below and above the ground.

Temperature

Wheat Peas Flax

10 0.66 0.50 0.2816 o.33 0.33 0.1623 0.24 0.28 0.14

The effect of Temperature on Root/Shoot Ratios in crops grown under optimal mineral and water

conditions.

After Van Doblen, 1962, given as shoot/root ratios converted to root/shoot ratios.

Distribution of the Earth's Eight Major Terrestrial Biomes .

(Adapted from: H.J. de Blij and P.O. Miller. 1996. Physical Geography of the Global Environment. John Wiley, New York. Pp. 290.)

Biomes

• Complex biotic community characterized by 

distinctive plant and animal species and maintained under the climatic conditions of the region, especially such a community that has developed to climax.

• Terrestrial (land) biomes• Aquatic biomes (including

Freshwater biomes and Marine biomes)

Tundra

• ‘tundra' from a Finnish word tunturi, meaning treeless plains

• coldest and harshest biome in the world• permafrost – permanent frozen deeper soil layer• vegetation mainly comprises of dwarf shrubs,

grass, moss and lichen• prominent animals are polar bears, arctic fox,

grizzly bear, Harlequin duck, musk ox, caribou and snow owls

Northern Coniferous Forest• occupies a vast area below the

tundra, extending completely across Canada and into interior Alaska.

• also referred as theboreal forest or taiga.

• Trees primarily possess pine needles instead of broad leaves like those of the temperate forests to the south.