Vaccari D.A., Strom P.F., Alleman J.E. Environmental Biology for Engineers and Scientists

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by primary production of ages past. The combustion of these resources is returning much

of this to the atmosphere. The CO

and other anthropogenic gas emissions have already

resulted in more than 1% increase in the amount of energy from the sun being trapped at

Earth’s surface (Section 14.2.2). Now the question is: What are the biological and ecolo-

gical effects of the greenhouse gases and the global warming that they are expected to

cause?

Because CO

is a reactant in photosynthesis, increasing its concentration would be

expected to increase primary productivity. Assuming that moisture and other nutrients

are readily available, a doubling of CO

increases aboveground biomass of plants by any-

where from zero to 50%. The C

plants will be more sensitive. Trees increase their pro-

ductivity by an average of 40% with CO

doubling. The C

plants are less sensitive, since

they have evolved mechanisms to concentrate CO

within the leaf. However, C

plants

may beneﬁt by being able to operate longer with their stomates closed, thus conserving

more moisture.

Ecological effects have been more difﬁcult to predict experimentally. One result tested

the effect of decreased moisture in arctic tundra. An increas e in global temperature is

expected to have uneven climate effects at different locations around the world. Normally,

biomass accumulates in these ecosystems because frozen permafrost is not available

to decomposers. A drop in water table level would expose this biomass to degradation,

converting the tundra from CO

sink to CO

source.

The leaves of plants grown at high CO

levels have a lower nitrogen content. Thus, the

many insects that are nitrogen limited and feed on these leaves may need to eat more to

satisfy their needs. As a result, a fall in insect numbers and an increase in plant damage

could both result.

The effect of warming itself is usually to increase growth rates of organisms such as

plants and insects. However, this is unlikely to occur evenly. Instead, competitive balances

are likely to be altered, resulting in signiﬁcant population shifts. Thus, the temperature

does not have to move outside the normal range of a particular organism in order to

harm it—it just has to favor a competitor or predator preferentially. Warm years in

western Canada and in Alaska usually result in pest outbreaks.

In some crustaceans, ﬁsh, and reptiles, sex is affected by the ambient temperature at a

critical time during gestation. For example, certain turtles, such as the loggerhead sea tur-

tle, produce a higher proportion of females as the temperature increases. This could affect

their population.

A small change in average temperature could produce a signiﬁcant shift in the seasonal

warming in the spring. This could disrupt timing of insect hatching, with consequences up

the food chain. For example, the emergence of the larvae of winter moth in Scotland is

more sensitive to spring temperat ures than is the opening of the buds of the sitka spruce

that they feed on. Thus, warming could reduce the overlap between egg hatching and bud

opening, reducing the survival of the moth larvae. Birds or other animals that eat the moth

would be affected. It is possible that the timing of the moth hatching could adjust itself by

natural selection. Genetic variation within the moth may include individuals that hatch

later. If so, these will be more likely to survive the changed climate conditions.

Migrations could also be affected by timing shifts. For example, many shorebirds

migrate from the tropics to the arctic along the east coast ‘‘ﬂyway’’ of North America.

They arrive at the Delaware Bay just when spring warming triggers horseshoe crab egg

laying. The egg feast provides the energy they need to complete their journey. When the

birds arrive at the arctic, they lay their eggs. The eggs hatch just before the peak in certain

568 ECOSYSTEMS AND APPLICATIONS

insects that the birds feed on. Thus, these birds are locked into climate-driven cycles of

other organisms. Ecologists fear that warming could disrupt one or both of these timings,

with disastrous effects for the shorebirds.

A population may respond to changing climate by shifting its range. However, in some

cases this may not work with changes caused by greenhouse gases. One reason is that the

data and predictions indicate that the temperature change is coming faster than in natural

climate changes of the past . Furthermore, human settlement has fragmented natural ter-

restrial ecosystems, isolating them into reserves or ‘‘ecological islands.’’ Thus, spatial

shifts may run up again st barriers of inhospitable environments, lacking appropriate

habitats or food sources.

It is thoug ht that polar regions will experience greater warming than lower latitudes.

Melting of the great ice sheets there could increase sea level several meters, ﬂooding

coastal regions around the world. Thermal expansion of the ocean due to warming can

also produce signiﬁcant changes. Already, the ocean level is increasing by about 2 mm

per year, although the cause of this trend cannot yet be proved.

Although many areas may experience increas ed precipitation with warming, others

may become dryer. Lake Manitoba, one of southern Canada’s largest lakes, was comple-

tely dry between 4000 and 6000 years ago when temperatures were 1



C warmer than

present. Few wetlands existed below 53



N latitude in this period.

In the Experim ental Lakes Area of northwestern Ontario, the air and water temperature

increased 2



C from the late 1960s to the late 1980s. Although this increase cannot be

blamed conclusively on greenhouse warming, it nevertheless serves as an example of

what could happen to similar ecosystems if such a change occurred for any reason. In

this case precipitation decreased and evaporation increased. Streamﬂow dropped, and

forest ﬁres increased, increasing runoff. These caused increases in dissolved solids and

nutrients in streams and lakes. Increased wind stresses on lakes deepened the epilimi-

nions, reducing the amount of cold hypolimnion on which many species, such as lake

trout, depend. The combina tion of higher temperature, increased nutrient content, and

reduced renewal rate resulted in increased algae blooms. Runoff from burned areas

contains sulfuric acid, which produc es a pulse loading of acidity to surface waters

which may add to the background acid loading caused by acid precipitation.

15.7 ACID DEPOSITION

Acid deposition arises from nitrogen and sulfur oxides that are produced by combustion

processes and fall on downwind ecosystems as nitric and sulfuric acids. The deposition

can be in the form of precipitation, including acid rain,orasdry deposition carried by

aerosols or dust particles. Even fog and dew may be acidiﬁed. Most of the nitrogen

originates from the air used in combustion, although some may come from the fuel,

such as from the burning of biomass. Sulfur oxides come exclusively from the fuel.

Coal and some crude oils are high in sulfur. Reﬁned fuels such as gasoline tend to

have much less. Emitted as SO

, at greater distances more and more of the sulfur is in

the form of sulfuric acid. Sulfur is usually a more important cause of acid rain than nitro-

gen is. Unpolluted rainfall has a pH of about 5.6. The most seriously affected area of

North America is in the northeast, where rainfall pH averages as low as 4.0 to 4.2. Indi-

vidual storms can be as low as pH 2 to 3. Acid deposition is being blamed for damaging

biological and chemical effects on forests, soils, and surface waters.

ACID DEPOSITION 569

Some of the direct effects of acid deposition on plants include eroding the cuticular

layer of leaves, interf ering with the normal function of stomatal guard cells, causing

necrosis of leaf tissue, disturbing photosynthesis, and producing premature senescence

(aging). Indirect effects include increased leaching of minerals and organics from

damaged surfaces, greater susceptibility to drought, parasites, disease and other stresses,

and alteration of symbiotic associations such as with mycorrhyzae fungi, nitrogen ﬁxers,

or lichen fungi.

Large areas of central Europe are experiencing severe forest damage. Here there are

thought to be interactions with other pollutants, such as ozone. The effect of acid rain

on forests is largely indirect, caused by changes in soil chemistry. Acid deposition solu-

bilizes aluminum, which in turn reduces absorption of calcium, mag nesium, and potas-

sium by roots. Nitrates absorbed from the air stimulate growth, but the lack of other

minerals obtained from the soil results in this growth being weak and susceptible to

disease.

In some cases, natural selection has resulted in an increase in tolerance of plants to

pollution compared to similar plants in unpolluted areas. Other responses include shifts

in populations. Several studies have shown correlation between the lichen species present

and sulfur dioxide concentrations. Higher SO

levels also correlate with a reduced number

of lichen species. However, many of these effects have been observed close to smelters or

coal-burning power plants.

The ecosystems that are most sensitive to acid deposition are aquatic. Most of the water

in aquatic systems ﬁrst fell on the land. Soil contains minerals, especially calcium and

magnesium, which neutralizes some of the acidity and provides buffering capacity.

This is especially true in areas underlain by limestone. Lakes in these areas are unaffected

even if rainfall is acidic. However, area s of granite bedrock have less soil buffering, and

aquatic systems in these areas are affected more severely impacted. The Adirondack

mountains of New York and the Scandinavian countries of Europe have a combination

of this type of geology and acid precipitation. In the 1930s only 4% of Adirondack

lakes had a pH less than 5. In 1975 the amount was 51%. Of the lakes in with pH less

than 5 in 1975, 90% had no ﬁsh.

Lakes that have normal pH ranges most of the year may experience shock loading of

acidity from snowmelt, when acidity accumulated throughout the winter is released at

once. Some lakes are acid naturally, due to organic acids produced by decomposition

of leaf litter. Lakes affected by acid deposition can be distinguished because they lack

bicarbonate, and the major anion balancing the cations hydrogen, calcium, and magne-

sium tends to be sulfate. Eutrophic lakes may be protected from acidiﬁcation because

nitrates are destroyed and alkalinity is produced in the anoxic hypolimnion by denitriﬁca-

tion and sulfate reduction. However, once pH drops below 5.4 to 5.7, nitriﬁcation is

inhibited and ammonium accumulates.

Lowered pH causes aluminum to leach from soil into streams and rivers. In the Adir-

ondack Mountains of New York State, 217 high-altitude lakes were found to have pH

from 4.25 to 7.33 and aluminum concentration from 10 to over 2000 mg/L. However,

almost all of the lakes with pH above 5.0 had less than 125 mg Al/L, whereas almost

all with pH less than 5.0 were at or above 125 mg Al/L. Aluminum forms insoluble

precipitates with phosphorus, removing this nutrient from the water column and reducing

primary productivity. As a result, acid lakes are more oligotrophic than normal and may

be exceedingly clear. Aluminum becomes toxic to ﬁsh below pH 6.2. Below pH 6 the

aluminum forms a precipitate on the gills of ﬁsh, interfering with calcium and sodium

570 ECOSYSTEMS AND APPLICATIONS

transport. The ﬁsh secretes mucus on the gills in response, and this reduces oxygen

transport.

Dissolved organic carbon (DOC) in water absorbs ultraviolet (UV) light, which is

harmful to algae. In the Experimental Lakes Area of Ontario, UV-B light normally pene-

trates 20 to 30 cm from the surface. When the lakes were experimentally acidiﬁed, the

DOC precipitated and settled. UV-B penetration increased to almost 1.5 m.

Fish are most susceptible to low pH just after hatching. Aquatic invertebrates

which provide food for ﬁsh at all stages may be affected. Lakes in Ontario and the

eastern United States lose their lake trout population when their pH falls below 5.6 to

5.2. The eggs and tadpoles of frogs and toads are sensitive, but other amphibians,

such as newts, are less so and may increase in abundance due to reduced competition.

However, if the pH remains below 5, all animals and many plants will be eliminated.

Some attached green algae and the acid-loving Sphagmum moss may ﬂourish, sometimes

maintaining primary productivity. Table 15.23 shows the impact of acidiﬁcation on a vari-

ety of animal groups. Many of the lakes experienced total elimination of mollusks and

leeches.

15.8 ENDANGERED SPECIES PROTECTION

In 1966, the U.S. Congres s passed the Endangered Species Protection Act. Initial ly, it

listed only animal species in need of protection, but the 1973 Endangered Species Act

(ESA) made plants and all classes of invertebrates eligible. It also implemented the

Convention on International Trade in Endangered Species of Wild Fauna and Flora

(CITES), which restricted internationa l trade in endangered species.

The ESA deﬁned a species as end angered if it is in danger of extinction within the

foreseeable future throughout all or a signiﬁcant portion of its range. In addition, a species

is deﬁned as threatened if a species is likely to become endangered within the foresee-

able future throughout all or a signiﬁcant portion of its range. The act prohibits federal

agencies from any actions that would harm a listed species or its ‘‘critical habitat.’’

Conservation plans and land acquisition were authorized. The ultimate goal of the act

is recovery of the species and removal from the list.

Amendments in 1982 required that the determination to add species to the list must

be made solely on the basis of biological and trade information. Economic or other

effects are not to be considered. However, 1988 amendments required that all reasonably

TABLE 15.23 Median Percent Reduction in Several Types

of Organisms in Adirondack Lakes That Have Been Affected

Severely by Acid Deposition, Compared to Unaffected Maine Lakes

Group of Organisms Adirondack Lakes Maine Lakes

Rotifers 40

Crustaceans 18 0

Mollusks 51 0

Leeches 60 0

Cyprinids 17 0

Percids 0 0

Source: Barnes and Mann (1991).

ENDANGERED SPECIES PROTECTION

571

identiﬁable expenditures be reported for each species undergoing recovery action by state

or federal governments. Table 15.24 summarizes the endangered and threatened

species list.

Tables 15.25 and 15.26 give examples of some of the plants and animals that are

endangered or threatened over a range of several states or more. Note that plants tend

to be endang ered or threatened over narrower ranges than animals. The southern U.S.

states of the tend to have the most listed species, in the range of 50 to 90 each. Except

for Florida, most of them are animals. The large number may be due to the species rich-

ness there, resulting from the warm, moist climate. California has 166 species listed, pos-

sibly because of its size and diversity of ecosystems. Hawaii alone has 300 listed species,

263 of which are plants. One reason may be the threat of exotic species, with which native

ﬂora are not adapted to compete. Alaska, on the other hand, has only ﬁve listed species,

and Maine has just eight.

A high proportion of the endangered and threatened animals depend on wetlands for

some part of their life cycle. The whooping crane (Grus americana) nest in marshes in

Canada’s Northwest Territories in the spring and summer, in water between 0.3 and 0.6 ft

deep. In the fall they migrate south, stopping at riverine wetlands along the way.

Ultimately, they arrive at the Aransas National Wildlife Refuge in Texas for the winter.

Hunting and habitat loss almost eliminated them. In 1941 there were only 15 individuals

left. By 1993 they had recovered to a population of 75.

Two of the species in Table 15.25 are mentioned because of the controversial economic

and political roles that they have played. These are the northern spotted owl (Strix occi-

TABLE 15.24 U.S. Fish and Wildlife Service, Division of Endangered Species, ‘‘Box Score’’

of Species Listings and Recovery Plans as of November 1997

Endangered Threatened

Group U.S. Foreign U.S. Foreign Total Species Species w/Plans

Mammals 57 251 7 16 331 41

Birds 75 178 15 6 274 74

Reptiles 14 65 19 14 114 30

Amphibians 9 8 7 1 25 11

Fishes 67 11 41 0 119 78

Snails 15 1 7 0 23 19

Clams 56 2 6 0 64 45

Crustaceans 15 0 3 0 18 7

Insects 24 4 9 0 37 21

Arachnids 5 0 0 0 5 4

Total animals 337 520 114 37 1008 330

Flowering plants 525 1 113 0 639 390

Conifers 2 0 0 2 4 1

Ferns and others 26 0 2 0 28 22

Total plants 553 1 115 2 671 413

Grand total 890 521 229 39 1676

743

Some species are listed more than once in different populations. Some entries represent entire genera or families

(e.g., lemurs and gibbons).

There are 477 approved recovery plans. Some cover more than one species, and a few species have different

plans for different parts of their range.

572 ECOSYSTEMS AND APPLICATIONS

dentalis caurina) and the snail darter (Percina tanasi). Both of these have been used in

efforts to stop or limit economic activity. The snail darter is a small ﬁsh that would have

been thr eatened by the construction of a dam in Tennes see. Opponents of the dam used the

ESA successfully to stop the project and protect the snail darter’s habitat. However, many

people did not feel that the survival of a tiny ﬁsh should have a higher priority than a

project that would have huge economic advantages for the region.

TABLE 15.25 Examples of Endangered and Threatened Animal Species by Region

in the United States

Species No. of States U.S. Region

Bat, gray (Myotis grisescens) 12 Southern and midwestern states

Bat, Indiana (Myotis sodalis) 21 East of the Rockies

Beetle, American burying (¼giant carrion) 8 East of the Rockies

(Nicrophorus americanus)

Beetle, northeastern beach tiger 6 Mid-Atlantic states

(Cicindela dorsalis dorsalis)

Beetle, Puritan tiger (Cicindela puritana) 5 Mid-Atlantic and northeast

Butterﬂy, Karner blue (Lycaeides melissa samuelis) 8 Midwest to northeast

Crane, whooping (Grus americana) 12 South-central to north-central,

including mountain states

Darter, snail (Percina tanasi) 3 Southern states

Eagle, bald (Haliaeetus leucocephalus) 48 Contiguous United States

Falcon, American peregrine 48 Continental United States,

(Falco peregrinus anatum) including Alaska

Fanshell (Cyprogenia stegaria) 8 South-central to midwest

Frog, California red-legged (Rana aurora draytonii) California

Mussel, dwarf wedge (Alasmidonta heterodon) 9 East coast states

Owl, northern spotted (Strix occidentalis caurina) 3 Northwest coastal states

Pearlymussel, all varieties 12 Midwest to southern states

(Tennessee alone has 16

endangered or threatened

species of pearlymussels)

Pelican, brown (Pelecanus occidentalis) 8 Gulf and west coast states

Plover, piping (Charadrius melodus) 34 East of the Rockies

Sturgeon, pallid (Scaphirhynchus albus) 13 South-central to northern tier

states

Tern, least (Sterna antillarum) 18 South central to northern tier

states

Tern, roseate (Sterna dougallii dougallii) 11 Atlantic coast states

Turtle, green sea (Chelonia mydas) 22 All coastal states except Alaska

Turtle, hawksbill sea (Eretmochelys imbricata)21

Turtle, Kemp’s (¼Atlantic) ridley sea 16

(Lepidochelys kempii)

Turtle, leatherback sea (Dermochelys coriacea)27

Turtle, loggerhead sea (Caretta caretta)24

Turtle, olive (¼Paciﬁc) ridley sea 7

(Lepidochelys olivacea)

Wolf, gray (Canis lupus) 10 Northern tier states

Woodpecker, red-cockaded (Picoides borealis) 13 Southern states

ENDANGERED SPECIES PROTECTION 573

A later controversy involved the northern spotted owl. This owl requires ‘‘old growth’’

forest for its habitat. Environmentalists tried to use the ESA to protect those forests. The

result was an acrimonious battle. Loggers portrayed environmentalists as preferring owls

to peopl e. Environmentalists pointed out that without protection the old growth forest

would soon disappear, eliminating the jobs that depend on that resource anyway. The

issue was resolved with a compromise that was protective of the forests.

These controversies have resulted in attacks on the Endangered Species Act itself,

which have the possibility of weakening the act in the future. The debate over old growth

forests also brough t the issue of sustainability into the public eye. Sustainability refers to

a system in which resources are not used faster than they are produced. Nutrient use in

steady-state ecosystems provides a good natural example of sustainability. Ecosystems

achieve sustai nability with respect to nutrients by limiting their consumption and by

recycling.

PROBLEMS

15.1. (a) Suppose that you are given the task of determining the habitat of a benthic

organism, say a worm or a clam. Make a list of questions you would need to know

the answer to in order to specify the habitat fairly completely.

(b) Suppose, instead, that you were asked to specify the organism’s niche. What else

would you want to ask?

TABLE 15.26 Examples of Endangered and Threatened Plant Species by Region

in the United States

Species No. of States U.S. Region

American chaffseed (Schwalbea americana ) 7 Southeastern states

Canby’s dropwort (Oxypolis canbyi) 5 Southern Atlantic coastal states

Eastern prairie fringed orchid 8 Northern states east of the

(Platanthera leucophaea) Rockies

Green pitcher-plant (Sarracenia oreophila) 4 Southeastern states

Harperella (Ptilimnium nodosum (=ﬂuviatile )) 7 Southeastern states

Marsh sandwort (Arenaria paludicola) 3 West coast states

Mead’s milkweed (Asclepias meadii) 5 Northern plains states

Northeastern (¼Barbed bristle) bulrush 8 Mid-Atlantic states

(Scirpus ancistrochaetus)

Pondberry (Lindera melissifolia) 9 Southeastern states

Running buffalo clover (Trifolium stoloniferum) 6 South-central to midwest

Sandplain gerardia (Agalinis acuta) 5 Mid-Atlantic states

Small whorled pogonia (Isotria medeoloides) 16 East of the Mississippi River

Swamp pink (Helonias bullata) 7 Southeast and Mid-Atlantic states

Ute ladies’-tresses (Spiranthes diluvialis) 5 Northern Rockies Mountain states

Virginia spiraea (Spiraea virginiana) 9 South-central states

Western prairie fringed orchid 7 Plains states

(Platanthera praeclara)

Water howellia (Howellia aquatilis) 5 Northwestern states

574

ECOSYSTEMS AND APPLICATI ONS

15.2. Adding com posted manure improves the friability and nutrient-holding capacity of

a soil. Why is it better for the manure to be composted instead of being added

untreated?

15.3. A lake receiving conventionally treated wastewater is starting to show signs of

eutrophication. You might be able to control the algal blooms by upgrading the

treatment plant for nutrient removal, but you must determine whether to require

nitriﬁcation/denitriﬁcation, phosphorus removal, or something else. How could you

determine the limiting n utrient in a laboratory experiment? What limiting nutrients

would you test for?

15.4. Name one or two advantages that each of the following types of phytoplankton has

over the other for survival in lakes: cyanobacter, diatoms, dinoﬂagellates.

15.5. Draw an hypothetical energy-ﬂow diagram for a river as it travels from its source to

its mouth. Show the allochthanous inputs, the different kinds of dissolved and

particulate organic matter, and exchanges with sediments, ﬂoodplains, salt marshes,

and its ocean discharge. Perform a similar analysis for nitrogen.

15.6. What advantages and disadvantages do constructed wetlands for wastewater

treatment have over conventional biological wastewater treatment?

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Barnes, R. S. K., and K. H. Mann (Eds.), 1991. Fundamentals of Aquatic Ecology, Blackwell

Scientiﬁc, Boston.

Berner, E. K., and R. A. Berner, 1987. The Global Water Cycle, Prentice Hall, Englewood

Cliffs, NJ.

Coler, R. A., and J. P. Rockwood, 1989. Water Pollution Biology: A Laboratory/Field Handbook,

Technomic Publishing, Lancaster, PA.

Connell, D. W., and G. J. Miller, 1984. Chemistry and Ecotoxicology of Pollution, Wiley, New York.

Garrison, T., 1993. Oceanography: An Invitation to Marine Science, Wadsworth, Belmont, CA.

Gause, G. F., 1934. The Struggle for Existence , Williams & Wilkins, Baltimore.

Hickman, C. P., Jr., L. S. Roberts, and A. Larson, 1996. Integrated Principles of Zoology, Wm. C.

Brown, Dubuque, IA.

Horne, A. J., and C. R. Goldman, 1994. Limnology, McGraw-Hill, New York.

Kent, D. M., 1994. Applied Wetlands Science and Technology, Lewis Publishers, Chelsea, MI.

Krebs, C. J., 1994. Ecology, Harper Collins, New York.

Mann, K. H., and J. R. N. Lazier, 1991. Dynamics of Marine Ecosystems: Biological–Physical

Interactions in the Oceans, Blackwell Scientiﬁc, Boston.

Masters, G. 1998. Introduction to Environmental Engineering and Science, Prentice Hall, Upper

Saddle River, NJ.

McKinney, M. L., and R. M. Schoch, 1998. Environmental Science, Systems and Solutions, Jones

& Bartlett, Sudbury, MA.

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Needham, J. G., and P. R. Needham, 1962. A Guide to the Study of Fresh-Water Biology, Holden-Day,

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Raven, P. H., R. F. Evert, and S. E. Eichhorn, 1992. Biology of Plants, Worth Publishers,

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Taiz, L., and E. Zeiger, 1988. Plant Physiology, Sinauer Associates, Sunderland, MA.

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576

ECOSYSTEMS AND APPLICATI ONS

BIOLOGICAL APPLICATIONS

FOR ENVIRONMENTAL CONTROL

Applied biology plays an altogether vital role for all humans, in terms of sustaining both

human life and environment quality. On the production side of these beneﬁts, we are all

highly dependent on the renewable genesis of consumable products, from farms around

the world that generate cultivated crops and managed livestock, from managed forests that

furnish new supplies of timber and pulp, and from extensive commercial and industrial

operations that supply a wide range of bioc hemical products ranging from basic foods

and beverages (e.g., bread, cheese, wine, beer) to bulk chemicals (e.g., acetic acid, etha-

nol) to advanced pharmaceuticals.

Given that waste generation inevitably follows our consumption of commodities, we

also depend heavily on controlled biology for yet another layer of applied beneﬁts, as

the biochemical basis for sustained environmental management. Indeed, we routinely

rely on applied biology to cover both source and sink roles in closing out the grand

mass balance of waste residuals within all environmental realms, from wastewater treat-

ment to biosolids processing to solid waste degradation to soil, groundwater, and air con-

taminant remediation.

These biochemical beneﬁts, therefore, are global in coverage while being evolutionary

in impact. Dating back roughly 10,000 years, applied biology had an absolutely seminal

impact on the advent of civilized human life, enabling our nomadic hunter–gatherer pre-

decessors to adopt an entirely new life-style tied to their newfound abilities with beneﬁ-

cially controlling and manipulating biology.

Rather surprisingly, though, the methods and motives of applied biology are not unique

to humans. In fact, based on what we know about the appro ximate origin of ant life forms

in the mid-Cretaceous Era 80þ million years ago and their sophisticated colonial life-

styles, it is quite likely that we trailed ants in this regard by a considerable margin. For

example, there are ant colonies that ‘‘farm’’ fungal growths for food, and there are even

Environmental Biology for Engineers and Scientists, by David A. Vaccari, Peter F. Strom, and James E. Alleman

577