Justus Von Liebig (1840)

-Developed

-Organic chemist, worked with plants

-Developed law of minimum by working with plant nutrition (water, micro, macronut.)

-Growth of plant is dependent on food, presented in min. quantity

-Law of min. eventually extended to cover all requirements of plants and animals.

-Limited by food, water, shelter (cc)

-Lack of water for spawning

-Too much, or too little water for nesting

-Applies to only steady state conditions, does not change over time.

-Factor interaction not considered: high availability of substance other than min. may modify rate of utilization of latter.

Factors or other restraints in the physical and biological environment of an organism that

-restrict growth

-interfere with reproductive success

-may cause death

Presence or success of organism depends on complex set of conditions --> law of min. 

-quantity and variability of materials, there is a min. requirement

-physical factors (temp., moisture)

-Limits of tolerance of organisms to components of environment (habitat, other organisms)

Factors that affect the extent of the relationship b/w an organism and its environment.

-Potentially limiting factors always present

-Time

-May be present with CC

-Animal ecologist

-Study both structural elements (plants, animals) of a community together. 

-Developed the Law of Tolerance

-Bell shaped curve (too little or too much stress)

-A species has a range of tolerance or requirements with a minimum on one hand and a maximum on the other. 

When conditions are not optimum for a species with respect to one ecological factor, the limits may be reduced with respect to other ecological factors.

-Organisms in nature are not living at optimum range (physical factor).

-Reproductive periods (environmental factors)

For each organism there exists a specific tolerance range for any essential environmental factor below or above which the organism's activity is adversely affected.

-Constraint growth and reproduction (pH for fish)

A species distribution is limited more by conditions of physiological stress than by the actual limits of tolerance.

-Death verges on the limits of tolerance

- Species existence would be jeopardized if too frequently exposed to limits of tolerance. 

Biome

Shelford and Frederick Clements (1877)

-Started with oyster beds (Karl Mobius)

Major natural unit of plants and animals

"Major life zone"

Living and non-living environment functioning as a self-organizing, self-sustaining system.

-Plants and animals interacting with the physical environment

-It requires/demands the most favorable levels of all factor intensities.

-An improvement in an environmental condition tends to favor population development.

Implies that wide variations in factor intensities are of little consequences in the region of the optimum

-bell shaped curve, pollution

-Closer the factor is to limit of toleration, the greater the relative impact of the change on the organism's behavior. 

-Stage of life cycle

-Time 

-Space

-Time of day

-Season

-Daily

etc...

-Geographically

-North

-South

-Up and down

etc...

The nature of the action of the environment on living organisms.

-All of the common conditions acting on the organism.

-all, common, condition

-Lehninger (1965)

A system which exchanges matter with surroundings. Can also exchange engergy.

-Energy can enter or leave the system.

-May create unstable relationships b/w population # and resource availability.

The capacity to do work. 

-Mechanical

-Chemical

-Radiant

-Heat

Open system and 

Populations

-Pops are dependent on matter and energy from outside sources.

-If flow and energy/matter is interrupted w/in the system, problems may develop.

Any system that does not exchange matter with its surroundings. 

-Amount of matter is fixed within a system.

-Radient energy can enter and leave.

Closed system and

Populations

CS have site-bound energy that is tied to matter cycle in the system.

-State of equilibrium b/w pop and resource use inside CS.

Resource Classification System

"Natural Resource Conservation"

No apparent finite supply or amount. Quantity will remain relatively constant. 

-Immutable

-Misusable (quality)

Incapable of much adverse change through man's activities

-Atomic Energy

-Wind power

-Precipitation

-Water power of tides

Quality impaired.

-Solar power

-Atmosphere

-Waters of oceans, lakes, streams

-Water power of flow streams

Those that can be completely used up.

-Maintainable

-Non-maintainable

Those whose quantity and quality are dependent upon man's use.

-Renewable (flow): living biota

-Non-renewable: Once gone, can't be replaced

RCS - Renewable

-Flow resources - rejuvenated

Living biota. Perpetual harvest depends upon proper planning and management.

-Water in place

-soil fertility

-products of land and water

-human powers

Once gone, can't be replaced: can't recreate it

-Species of wildlife

-wilderness 

-oligotrophic lakes (few food)

Primarily mineral resources. Total quantity is static. Can't be replaced when used. 

-Reusable

-Non-reusable (stock)

Stock

Fossil fuels/oil

non-metallic mineral

coal

-Group of individuals of single species

-Structure, function, and adaptations to diverse environmental conditions or other pop's

-Characteristics different than that of individual (age structure, sex ratios...)

-Species pop's occupy same place at same time.

A group of individuals (plants, animals) or objects agreeing in common attributes and designated by having the same name.

-Heterosexual vertebrates

-Terrestrial vertebrates (mammals and birds), also reptiles, amphibians.

-NOT fish/invertebrates (Hanson).

The time it takes to replace all individuals in a pop.

-New individuals through birth and immigration.

Rate at which young individuals replace older individuals

-Annual measurement

-Stability ≠ static conditions

-Few orgs. live to old age in wild

-Individuals w/in pop change rapidly, even though total number remains constant from period to similar time period.

still waters

-lakes

-reservoirs

Flowing waters

-streams

-rivers

Salmonids

-trout

-salmon

-white fish, grayling

Less than 20° C

-Bass

-Bluegill

-perch

-catfish

More than 20° C

Wild

Think boars

Non-native (and stocked fish) adapted, which have become established in an area and naturally reproduce 

-"put and take" fisheries

Anadromous 

Fish

Up!

Running upward. Adults travel upriver from sea to spawn. Return to sea.

-Salmon, steelhead

Diadromous

Fish

Between!

Migrate b/w fresh and salt water

-eels, carp

Catadromous

Fish

Live, lay elsewhere

Live in fresh water, migrate to salt water to lay eggs.

-eels

Oceanadramous

Fish

Both spawn and feed as adults in open water of ocean.

-Move around to different areas of the ocean.

Irregular growth patter, unstable numbers, erratic, unpredictable

-Favorable conditions that occur from time to time (weather, climate, good habitat)

-Normal cycle, stable, but can increase suddenly

Fluctuations/cycles

Types

Stable

Cyclic (periodic/less stable)

Irruptive

NO wildlife pop is constant in numbers

due to:

Why a pop fluctuates through time...

-gains from birth

-losses from death

-emigration

-immigration

-migration

Steady state (input = output)

Relatively constant in number from period to similar period.

-Minor ups and downs from births and deaths (CC)

-Biomes with constant temp. and rainfall

Cyclic cycle

(Periodic)

-Two types

Less stable, fluctuate at regular intervals.

-Short (3-4, 2-5 years) and 10-year

-Biomes with low temp. and rainfall (arctic, temperate)

-Less complex communities

-Buffer species live longer, less importance (hare)

3-4, 2-5 years

-Lemmings, mice overrun natural habitat

-Tied to cycles of natural predators (fox, owl)

-Time lag effect

Time lag effect

-Short year

-American game birds

-Not well studied, but well known

-Time involved 

-Affect great # of species at same time

-Boreal forest

Way a pop responds to new environment through time, or the carrying capacity of the environment. 

-basic GC express the slope of a pop's growth when organisms introduced to new environment. 

-Biotic potential (push up) and environmental resistance (push down)

Biotic Potential (GC)

Flies and DDT

-Good light, temp, chem. environment

-High repro rate

-Generalized niche

-Good food supply, habitat

-Can compete, defend themselves

-Health

-Migrate/adjust

Environmental Resistance (GC)

Decimating Factors

-Bad light, temp, chem. enviro.

-Low repro. rate

-Specialized niche

-Bad food supply, habitat

-Too many competitors, can't defend

-Bad health

-Can't migrate/adjust

Max. sustained rate of natality and min. rate of mortality.

-Rate of increase limited by physiological limitation of species, not environment

Sum total of all decimating (Limiting) factors, operate to cause mortality.

-Prevents Biotic Potential from being realized.

Nr = dN/dt (# offspring/period of time)

-Exponential, uncontrolled growth

S = Nr [(K-N)/K]

-When a species becomes established in new habitat with good CC

J-Shape

S-Shape

-show type of pop growth exhibited in situations where

-CC of habitat is constant

-BP of species modified by density dependent factors.

-Increase in intensity as pop numbers approach CC of the environment.

-Mortality increases as pop increases.

population size at a point in time

o is point of starting

Maximum rate of increase

-# of organisms that will breed (females)

Raymond Pearl 

and 

L.J. Reed (1920)

-Broad terminology and classification system

-Dynamics of energy flow and nutrient cycles at the community and ecosystem level

-Man's role as a principle factor of change in the resources of natural systems

-Historical perspective which includes important people and dates

-A fundamental truth that explains the relationship b/w 2 or more variables.

-It is descriptive and predictive, NOT prescriptive.

-Was synthesized from observation

-Can't be disproved, but can be modified through time.

-Describes some regularity, relationship w/in a group of facts

-an element of memory

-vehicle of thought

-entity by means of which thinking is carried on

-is not the meaning in the sense of things signified

-an explanation of a potential law of nature

-a belief or procedure proposed or followed as the basis of action.

-a plausible general concept or body of principles offered to explain phenomena

-unproved assumption

a tentative assumption made in order to draw out and test its logical or empirical consequences.

-Proposition thought to be true because its consequences are true. 

-Has NOT been tested

Living systems consume and produce energy.

-Energy in plants = Primary Production

The maintenance of constancy w/in a biological system. In terms of interaction b/w organisms in a community or internal environment of an individual. 

-All living systems are in equilibrium with the environment

-Number of organisms forming a series through which energy is passed. 

1. First trophic level: green plant (autotroph), traps energy, makes food for consumer levels. 

Cycle involving movement of more earth bound elements: 

-Erosion

-sedimentation

-volcanic activity

-mountain building

Elements that pass back n forth b/w organisms and environment, many involved in sedimentary cycle. 

-No known value to organism, but concentrated in tissues, similarity to vital elements.

-Atomic bombs = radioactive isotopes of these elements and get into environment and food chains. 

Cycling of chemicals like carbon, oxygen, phosphorus, nitrogen and water w/in (intrasystem) or b/w (intersystem) ecosystems. 

-Assimilated and broken down over n over again by organisms

Population Properties

It has characteristics above that of the individual, like age structure, sex ratios, etc. 

-Generally function of food, water, shelter. 

A rough estimate of population density of a given species. 

(Number of individuals in period of time/total species in community) = percentage

Occurrence of organisms in isolation from others of their species

-desert shrubs

Different species that have similar roles (niches) in similar ecosystems located in different parts of the biosphere

-anteaters in South America, aardvarks in Africa