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The Real Scoop on Dirt "More organization and complexity exist in a handful of soil than on the surface of all the other planets combined.”

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Presentation on theme: "The Real Scoop on Dirt "More organization and complexity exist in a handful of soil than on the surface of all the other planets combined.”"— Presentation transcript:

1 The Real Scoop on Dirt "More organization and complexity exist in a handful of soil than on the surface of all the other planets combined.” *************************************Edwin O. Wilson Harvard University SAFS

2 So what lives in soils? “The soil is alive and the diversity is enormous. One square foot of soil has an array of small invertebrates, mites, arachnids... hundreds, or even thousands of species, many of which are still unknown to science.” E.O.Wilson

3 Nematodes (round worms)
Protozoa feed on bacteria and fungi 10 million /m2 (3 to 20 g/m2) Nematodes (round worms) feed on bacteria, fungi, protozoa and plant roots 10 million /m2 in grassland soils, 30 million /m2 in woodland soils Enchytraeids (pot worms) feed on dead plant material /m2 in grassland (50-35 g/m2) Tardigrades (water bears) 50 to 500 /m2 Pauropoda 20 to /m2 Molluscs (Slugs and Snails) feed on rotting vegetation (+ a few carnivorous species which eat other molluscs) approx. 15 /m2 in grassland soils, 450 /m2 in woodland soils

4 Diplopoda (Millipedes)
Symphyla feed on fungi up to 1000 /m2 in grassland soils, 3000 /m2 in woodland soils Isopoda (Woodlice) feed on fungi, and dead plant material 500 to 1500 /m2 in grassland soils, 3000 /m2 in woodland soils Diplopoda (Millipedes) approx. 20 /m2 in grazed grassland, 100 /m2 in ungrazed grassland, 100+ /m2 in woodlands Chilopoda (Centipedes) feed on insects an other soil arthropods approx. 120 /m2 in grassland, 150+ in woodlands Aranaea (Spiders) feed on other arthropods 480 /m2 in Moorlands, 200 /m2 in pasture

5 Acari (Mites) feed on everything 100,000 to 600,000 /m2 woodland soils Collembola (Springtails) feed on fungi and bacteria 40,000 to 70,000 /m2 in grassland soils, /m2 in coniferous woodland Coleoptera (Beetles) up to 2000 to 3000 /m2 in ungrazed grasslands, considerably lower in arable soils. Hymenoptera (Ants) feed on other arthropods and plants secretions important soil movers

6 Today’s topics Taxonomy The n-dimensional ecological niche
Aravalli, She and Garrett Archaea & the new age of microorganisms. The n-dimensional ecological niche Silvertown, J Plant coexistence and the niche. Soil food webs and crazy soil critters!

7 Taxonomy = naming and classifying organisms into groups that share similar characteristics
Taxon = a taxonomic group or level Taxa = plural of taxon Linneaus ( ) Systema Naturae Physician - studied medicinal plants Father of taxonomy Linneaus - check this for more info on Linneaus

8 Linneaus’ hierarchy Imperium ("Empire") - the phenomenal world
Regnum ("Kingdom") - the three great divisions of nature at the time - animal, vegetable, and mineral Classis ("Class") - subdivisions of the above, in the animal kingdom six were recognized (mammals, birds, amphibians, fish, insects, and worms) Ordo ("Order") - further subdivision of the above - the class Mammalia has eight Genus - further subdivisions of the order - in the mammalian order Primates there are four. e.g. Homo Species - subdivisions of genus, e.g. Homo sapiens. Varietas ("Variety") - species variant, e.g. Homo sapiens europaeus.

9 King Philip Came Over For Games Saturday
Binomial nomenclature Genus species Kingdom Class Order Genus Species Taxonomy of Fido Phylum Note addition Family King Philip Came Over For Games Saturday

10 The problem of common names - this fish is a:
Look ma, I think I caught a snake … Northern pike Common Pike Great Northern Pike Jack Jackfish Northern Pickerel Pike Snake G嚇da (Swedish) tika obecn� (Czech) kinoje (Ojibwe) Esox lucius

11 Oh, naaaa …. its just a squirrel
This is for you, Joey and John! I couldn’t resist!!

12 Back to taxonomy … what were those groupings anyway
Back to taxonomy … what were those groupings anyway? It depends on who you ask … Linnaeus ’s 2 kingdoms Plantae, Animalia Ernst Haeckel - early 1900’s 3 kingdoms Plantae, Animalia, Protista Robert Whitaker 5 kingdoms Plantae, Animalia, Protista, Fungi, Monera Karl Woese 3 domains Bacteria, Archea, Eukarya

13 The 5 Kingdoms Based on morphology, reproduction, metabolism, etc.
In general, the height up the “tree” represents time

14 The 3 Domains Bacteria Eucarya Archea Based on molecular structure of 16S or 18s subunits of ribosomal RNA Fungi Plantae Animalia Proteobacteria Cyanoobacteria Euryarchaeota Crenarchaeota Animalia Chloroplasts Mitochondria Adapted from McGraw-Hill Pub.

15 X-ray crystallography image of ribosome structure
University of California, Santa Cruz 16s rRNA of 3 spp. Universal Similar function Changes slowly Can be compared between organisms McGraw Hill Pub.

16 Dendrogram of 3 domains Bacteria Archea Eucarya McGraw-Hill Pub. And this brings us back to Aravalli, She and Garrett, Archaea & the new age of microorganisms

17 Why were these authors so excited?
Archea are no longer just extremeophiles!!! They’re ubiquitous!!! Will this change our thinking on: how food webs work? how organisms are related? how microbial communities are organized? how soil communities are organized? IUPUI Dept. of Biology

18 And this brings us to the concept of an ecological niche
Grinnell (1917) - the sites where organisms of a species can live Elton (1927) - the function performed by the species in the community Gause (1934) - intensity of competition determines overlap of niche Hutchinson (1957) - a region (n-dimensional hypervolume) in a multi-dimensional space of environmental factors that affect the welfare of a species

19 Species that need the same resources must compete
They either coexist or one will die out

20 General theory has been - to coexist, spp
General theory has been - to coexist, spp. must use resources in slightly different way Time of resource use Diurnal, crepuscular, or nocturnal feeding Early or late spring nesting for owls/hawks Particular part of resource used Seeds versus nectar versus leaves of a plant Large versus small seeds Area of tree canopy used by bird spp. (MacArthur) More or less efficient use of same resource Both maples and paw paw need sunlight, but paw paw need less

21 So how do so many spp. of plants coexist? (Silvertown)
If plants all use same few resources, why so many spp.? Two possibilities: Niche model is wrong Plant niches ARE different (we just don’t know enough to know HOW they differ) Conclusion --> differences have not been studied sufficiently Not asking the right questions (4 tests of niche separation) Studies should test all 4 of these when determining how plants use resources to see if niche model applies equally to plants One difference = mycorrhizae And that takes us right back to ……soil communities


23 Communities rule! The amount of decomposition was greater with soil macrofauna than without Hättenschwiler and Gasser 2005 Fig. 3. Total remaining litter mass of entire microcosms as a function of total predicted litter mass remaining. Data points represent individual microcosms either without macrofauna (open circles) or with macrofauna (i.e., millipedes, earthworms or both; solid diamonds).

24 And diversity matters for tough biodegrabables!
Fig. 1. Litter mass of individual species predicted from monocultures of the respective species and animal treatments. (Left) Data from the three more slowly decomposing species are shown. (Right) Data from the more rapidly decomposing species. Hättenschwiler and Gasser 2005

25 Roles of soil critters:
Decomposition Nitrogen fixation Mineralization Primary production

26 (Soil around plant roots)

27 Thanks to Dr. Nancy Nicholson for the following images and fun facts!

28 Nematodes and fungi - an “inversion of the animal-eat- plant relationship”
Background Nitrogen is inert in the atmosphere, so doesn’t mix with soil Nitrogen in soils is a limiting factor for plant growth Nematodes and fungi abound in healthy soils - both are essential for healthy plants because they retain nitrogen (and other nutrients) in soils once it has been captured by nitrogen-fixing bacteria The nematode - fungus relationship keeps nitrogen from going back to the atmosphere as a gas (methane)


30 Capture mechanisms of fungi
Paralyzing toxins (see <-- Hohenbuehlia) Traps - numerous designs but mainly sticky lethal lollipops sticky nets sticky spores sticky rings constricting rings (really scary!)


32 Fast Food... those Golden Arches should be so efficient...
Catenaria spores germinating on an infected nematode Myzocyctium spores inside a nematode


34 Sticky spores adapted to being eaten by bacterivore nematodes

35 Arthrobotrys, the fungus with it all!

36 The deadly constricting rings - rings rupture along line of weakness as nematode crawls through - moisture from the soil causes them to swell and … the fastest food in the west!

37 More deadly rings

38 Phragmospores of some nemtode-trapping fungi germinate as constricting rings if nematodes are present

39 And yes, there is the usual relationship of animal-eat-plant
And yes, there is the usual relationship of animal-eat-plant. Above right, a nematode avoids the paralytic toxin of the oyster mushroom and feeds on fungal tissue


41 Cyanobacteria in tufa mounds, Mono Lake, CA
Nealson, 1999 Cyanobacteria in tufa mounds, Mono Lake, CA pH = 10 hypersalinity Siberian permafrost core - frozen 1 million years

42 Halobacteria in salt crystals Salt mounds in Dead Sea
Nealson, 1999 Halobacteria in salt crystals Salt mounds in Dead Sea Salt ponds near Sn Francisco Bacteria in stomachs of invertebrates in amber

43 Population distribution by county 1800 - 1990
Percent of land in farms by county


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