ECOLOGICAL

PRINCIPLES

Concept 1

Ecology

BIOSPHEREa thin blanket of life surrounding the

earth which arises when atmosphere, land and sea meet

– most fragile layer of the earth– 10 miles thick (5 miles up into

atmosphere, 5 miles down into ocean)– ecosystems exist within the biosphere

Arrangement of the Biosphere

COMPONENTS OF A BIOMEBiomes are large geographic areas

defined by:-climate (temp, rainfall…)-soil type-type of plants

(plants determine animals)

Which division of the biosphere

contains all other divisions??

Question?

From looking at the diagram, formulate your own definition of community!

…hint…Think about what is included and what is not included

Ten Major Biomes

mediumabsentlowpoorsummer mild,winter cold

lowTundra

sparsedensemoderatepoor, acidicsummer mild,winter cool

moderateBoreal Forest

sparsedenselowrocky, acidicsummer mild,winter cold

highNorthwesternConiferous Forest

sparsedensehighrichsummer moderate,winter cold

moderateTemperate Forest

mediummediumlowpoorsummer hotsummer low,winter moderate

Temperate woodlandand Shrubland

denseabsentmoderaterichsummer hotmoderateTemperate Grassland

sparsesparsemoderatepoorvariablelowDesert

dense

medium

sparse

Grasses

sparse

medium

dense

Trees

moderateclaymildvariableTropical Savanna

moderaterichmildvariableTropical Dry Forest

highpoorhothighTropical Rain Forest

DiversitySoilTemperaturePrecipitationBiome

This is not in your notes because it would not copy well!!!

Biome terms• Diversity-number of different kinds of

living and non-living “things”

• Temperate-distinct seasons

• Tropical-consistently warm

• Deciduous-plants shed leaves

• Coniferous-leaves are year round

Question?

What is the biome description here at Central Dauphin?

• ECOSYSTEM: a place where relationships between biotic and abiotic factors are affected by geology and climate– energy is processed through the

biotic components– interrelationships create stability– populations are the basis of

ecosystems

• BIOTIC: living organisms (plants and animals)

• ABIOTIC: non-living (water, minerals, soil…)

• POPULATION: the number of organisms of the same species

• SPECIES: organisms that can interbreed and produce fertile offspring

Mic

rocl

imate

s

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HABITATS

• small subdivisions of an ecosystem where biotic components live and acquire the basic requirements of life

• must include essential abiotic components

• BASIC REQIREMENTS: food, shelter, water, space, air

Habitat is the ADDRESS• varies in size • habitats overlap between different

species• varieties of habitats increase

diversity

• BIODIVERSITY: number of different kinds of organisms within the ecosystem

DIVERSITY = STABILITY

• survival of the ecosystem is dependent on its diversity

• the greater the diversity, the more likely an ecosystem could survive a cataclysmic event (like an extinction, volcano…)

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EDGES ARE VERY STABLE

• the edge habitat (place where 2 habitats overlap) has the greatest diversity of plants and animals

• edge is usually more stable than either of the 2 habitats it divides

• edge shares species from both habitats as well as supporting edge only species

This is not in your notes!

This is not in your notes!

Concept 2

Population Dynamics

POPULATION DYNAMICS• Explains how wild populations control

and maintain themselves

• Based on the idea that resources are limited (CARRYING CAPACITY)

• All species (plants and animals) must have the BASIC REQUIREMENTS OF LIFE– -FOOD, SHELTER, WATER, SPACE, AIR– AND OF COURSE THE RIGHT CLIMATE

POPULATIONS

• Members of the same species

• Populations are limited in “range” by habitat, geology, climate and limiting factors within their habitat

• Tends to be maintained within the carrying capacity and critical number

LIMITING FACTORS• something that maintains

population size within the habitats carrying capacity

1. Food 7. Climate2. Competition 8. Disease3. Predation4. Geology/geography/topography5. Human influences6. Lack of any requirement of life

Carrying Capacity

• CARRYING CAPACITY: the number of organisms of a species that a habitat can support (provide basic requirements)

Example: The pond can support 25 frogs. What may limit the number of frogs?

Consequences

• breaking the carrying capacity will cause collapse of the population

• may lead to extinction• may reduce gene pool• may just reduce numbers long

enough for the habitat to recover

Can Carrying Capacity Change?

• Yes• Increases with habitat improvement

– Decrease in abusive population– Better weather promoting good food

• Decreases with habitat destruction– Increase in populations above carrying

capacity– Cataclysmic event (volcano)– Changes in climate (global warming?)

Critical Number

• The lowest number a species can drop to in an ecosystem and still recover– Set by nature to maintain genetic

diversity– Prevents in-breeding and passing on

“bad genes”

Populations may stabilize• Stable populations will fluctuate

between the carrying capacity and the critical number.

• Most species with proper limiting factors will function along these lines

• This is called DYNAMIC EQUILIBRIUM• These are called S-Curve populations

S-curve Populations

Carrying Capacity

Critical Number

TIME

NU

MB

ER

Draw your own in your notes!!!

causes of stabilization

• Emigration• Immigration These are• Death limiting

factors!• birth• predator-prey• disease

J-curve Populations

• Are not stable populations• Usually crash after they break carrying

capacity• Due to lack of limiting factors or it has a

special reproductive strategy– -many young with lack of parental care such

as fish

• May be an invasive species (gypsy moth)

J-curve Populations

Carrying Capacity

NU

MB

ER

TIME

Critical Number

Extinction

Recovery

Draw your own in your notes!!!

Species Interact with each other to maintain energy and population balances

• Predator-Prey relationships

Predators and Prey regulate each others populations ?

• Competition

-attempt to use the same limited resources

-limits population size between competitors

Categories of Competition

• Interspecific:

competition between 2 or more species for a single resource

• Intraspecific:

competition between members of the same species

-usually for mates or nesting habitat or territory

Bay-Breasted WarblerFeeds in the middlepart of the tree

Yellow-Rumped WarblerFeeds in the lower part of the tree andat the bases of the middle branches

Cape May WarblerFeeds at the tips of branchesnear the top of the tree

Spruce tree

Section 4-2

Figure 4-5 Three Species ofWarblers and Their Niches

Go toSection:

Interspecific competition shows how competition can be avoided by sharing resources (RESOURCE PARTITIONING). This guarantees that all species survive and increase diversity

• Parasitism

-lives on or in a host species

-often host specific

-generally causes harm or death of host in extreme situations

• Mutualism

-both organisms will benefit from the arrangement

-symbiosis arises through coevolution

• Commensalism– one member of the relationship

benefits– one member of the relationship gains

nothing, but is not harmed

example: lichens growing on the tree benefit from the tree, but the tree is not harmed or helped by the lichen

Concept 3

Flow of Energy

Energy is processed Feedback

input energy ecosystem output energy

-this allows the ecosystem to maintain an energy balance

FLOW OF ENERGY

NICHE = JOB

• the way an organism makes a living in their habitat

• niche describes how the organism gets it energy– producer (autotrophs and herbivores)– consumer (carnivores, scavengers)– decomposers

NICHE WHAT THEY EAT TYPES OF ORGANISMS

Autotroph Sunshine—these organisms make their own food

Plants (the green guys)

Herbivore Plants Bunnies, deer, bees

Carnivore other animals-general term

Lions, anteaters, fox, bass

Predator Hunts, kills, eats other animals

Lions, anteaters, fox, bass

Parasite Lives on or in living organisms, on their body materials

Ticks, tapeworms, fleas

Omnivore Both plants and animals Bears, people, skunks

Scavenger Dead or dying animals Vultures, crows, crayfish

Detritivore Dead plants and leaves Beetles, fungus

Decomposer Small particles and dead portions of other organisms

Bacteria, fungus

– photosynthesis in autotrophic organisms converts sunlight energy into carbohydrates (BIOMASS)

– they use oxygen to accomplish this– organisms are called photosynthetic

autotrophs (plants and algae)

THE SUN IS THE SOURCE OF ENERGY FOR ALL LIVING THINGS (almost)

• BIOMASS: the total weight of living matter in an ecosystem

• It accumulates in the food chain as processed energy

• Energy can be “lost”

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exception to the rule

• CHEMOSYNTHESIS– organisms make carbohydrates out of

carbon dioxide, water and inorganic compounds (like sulfur and nitrates)

– organisms are called chemosynthetic autotrophs (deep ocean bacteria)

Chemosynthetic organisms

Deep Ocean Ecosystems

FOOD CHAINS• a series of organisms which pass

energy from one feeding level to the next

• This process coverts one form of biomass to another

• these levels are called TROPHIC LEVELS

TROPHIC LEVELS

• Primary Producer• Primary Consumer• Secondary Consumer

• After secondary you can call them “higher consumers” by referring to their trophic level (3rd consumer, 4th consumer…..)

• always contain: sun, primary producer, decomposer– primary producer are autotrophs

• the arrow points in the direction the energy is being transferred to

• always flows in one direction• reads as “is eaten by”

Food Chains

examples

sun carrot rabbit bacteria

sun acorns squirrel hawk bacteria

sun grass deer bear human bacteriaenergy

Primary producer

Primary consumer

Decomposer

some general rules

• Large carnivores do not eat large carnivores

• herbivores do not eat carnivores• organisms within an ecosystem

may compete for food sources• interacting food chains are called

FOOD WEBS ?

WHATS MISSING? ?

ENERGY PYRAMID or PYRAMID OF BIOMASS

-biomass decreases at each step in a food chain

-energy is lost at each step: bones not used, fur, energy expended in eating and metabolism, feces….

Energy lost

90% used/lost at each level

10% to next level

• larger organisms require more energy so there will be fewer at the upper levels

• the shorter the food chain, the more organisms you can feed at the upper levels

1 human

300 trout

90, 000 frogs

27, 000,000 grasshoppers

1000 tons of grass

900 human

27, 000,000 grasshoppers

1000 tons of grass?

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IV. MATERIALS CYCLE

• MATERIALS CYCLE IN ECOSYSTEMS– water cycle– carbon cycle

– nitrogen cycle

All elements will cycle because the earth will run out of material if it does not!

WATER CYCLE

Water Goes UpEvaporation- heat causes the conversion

of liquid water into gaseous water (water vapor)

Transpiration- the evaporation of water from the surfaces of leaves-water is produced during photosynthesis

Water changes form

Condensation- due to cooling, gaseous water forms liquid water on the surface of a condensation nuclei

Condensation nuclei- a small solid particle of matter in the atmosphere on which water will condense

Water comes downPrecipitation-the falling of a condensed

form of water from the atmosphere-could be solid or liquid-occurs because the amount of water on the condensation nuclei becomes heavy and gravity causes the drop to fall

3 places water goes

1. Runs off into rivers, lakes, streams, wetlands

2. Percolates into the soil and is absorbed into plants

3. Percolates into the aquifer

Percolate: to move into an area occupied by air and fill the molecular space

The Aquifer

•Aquifers are underground layers of porous rock or sand that allows the movement of water between layers of non-porous rock (sandstone, gravel, or fractured limestone or granite).

• Water infiltrates into the soil through pores, cracks, and other spaces until it reaches the zone of saturation where all of the spaces are filled with water (rather than air).

• The zone of saturation occurs because water infiltrating the soil reaches an impermeable layer of rocks which it can not penetrate any further into the earth

• Water held in aquifers is know as

GROUNDWATER

• The top of the zone of saturation is known as the WATER TABLE. – .

-The water table typically follows the form of the above ground topography. -The water table levels can change Drier =deeper wet areas =at or near surface

• Two main forces drive the movement of groundwater– First water moves from higher

elevations to lower elevation due to the effect of gravity

– Second, water moves from areas of higher pressure to areas of lower pressure

– Third, water moves at a rate and amount related to the size and amount of spaces in the rock layer

Movement of ground water takes time—how much is variable, depending on the material it moves through and how deep you go.

CARBON CYCLE

Carbon Cycles through

A. Food chains and Food Webs as biomass

B. Decomposers release carbon as both a gas and an element

C. Respiration of plants and animals

Natural Sources of Carbon include: plants and animals, soil, fossil fuel deposits, atmosphere, humus…..

-any form of biomass will be a place of carbon storage

Man-made Sources of Carbon include: burning of fossil fuels and other organic materials

Carbon SinksCarbon Sink -long term storage of carbon

3 long term carbon sinks-deep ocean waters -deep ocean sediments -fossil fuel deposits

Short term carbon sinks-plants and animals-atmosphere

NITROGEN CYCLE

Nitrogen cycles throughA. Food chains and food websB. Decomposition of biomassC. Water

Natural Sources of nitrogen: biomass, decomposition, lightning, volcanoes

Man-made Sources of nitrogen: fertilizers, industry, combustion of fossil fuels

Nitrogen must be “fixed”Nitrogen is made in nature in an elemental form

N2

-most living things can not use this form

Nitrogen fixation -the process in which nitrogen fixing organisms convert N2 into useable forms

-Nitrogen fixing Bacteria and Legumes are symbiotic organisms which fix N2

-fixed forms include Nitrates NO3-, Nitrites

(NO2-) and Ammonia (NH4

+)

V. ECOSYSTEMS CHANGE

• SUCCESSION CAUSES CHANGES IN ECOSYSTEMS– ecosystems are never static– ecosystems tend to move from less

diverse to more diverse systems

low species high species

diversity diversity

more energy less energy

available available

less biomass more biomass

Primary Succession

• occurs where no ecosystem has occurred before

• uses pioneer species (lichens, moss) to form soils

• begins on rock• often accompanies a

cataclysmic event

Pioneer Species• small plant organisms like

lichens and mosses• their “roots” will gradually

break off small chips of rocks

• as they grow and die, the organic material mixes with the chips of rocks

• soils begin to form (200 years = 1 inch of top soil)

Secondary Succession

• occurs in areas of disturbance of existing ecosystems

• species who are opportunistic will begin process

• opportunistic species are generally fast growing and have a high reproductive rate

There are natural patterns of succession.

-fields become forests

-ponds become fields

-forests will change types of vegetation until maturity

Maturity• ecosystems will become more

complex• complexity slows rates of change• the higher the maturity, the longer

the ecosystem will stay in that state• in general--fields become shrub lands -- shrub lands become forests -- ponds will become grasslands

• as the ecosystem changes, the species composition changes

Fire Maintained Ecosystems

• tends to halt/slow succession • maintains a particular successional

state• some species require fire for

reproduction• fire is used as a management tool

to maintain ecosystems

Climax Communities

• all ecosystems tend to move toward an idealistic end state called a climax community

• arguments occur about its existence

• climax allows for very little change

Concept 6

InvasiveKeystone

Native

Invasive, Endangered, and Keystone Species

• Invasive: a species that did not evolve in the habitat, it was released on purpose or by accident

• Endangered: a species which are so close to the critical number that it may become extinct in the near future

• Keystone: a species which is critical to the survival of an ecosystem-they are tied to many other species

Invasive SpeciesGypsy Moths introduced into this country in 1869 have devastated much of the eastern oak forests. Non-native species do not have limiting factors to control their populations. This causes elimination of native species.

Rabbits introduced into Australia have devastated the native grasslands and endangered kangaroos and other native wildlife.

Endangered

California CondorThe largest bird of North America was brought to the brink of extinction due to:

-over hunting

-habitat destruction

-egg collecting

-DDT (pesticide)

• In 1987, the last wild condors were removed and placed with the remaining population in captivity-there were 26

• A captive breeding program is in effect and as of 2012 there were 405 birds (226 in wild, rest in zoos)

• Scientists question if they had reached the critical number as all 27 of the first breeding population had originated from 14 birds

KEYSTONE SPECIES- organisms which are important in shaping the total ecology of an ecosystem

Cray fish and Beaver are both keystone species in Pennsylvania. It is because they form habitats (like beaver) or are a major food source for many organisms. Either way they have major influence over their ecosystems. Loss of these species would result in ecosystem collapse.

The Endangered Species Act

• The law requires federal agencies, to ensure that actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of any listed species or result in the destruction or adverse modification of designated critical habitat of such species.

• The law also prohibits any action that causes a "taking" of any listed species of endangered fish or wildlife. Likewise, import, export, interstate, and foreign commerce of listed species are all generally prohibited.

Trophic Cascadehttps://connect.usu.edu/p24408776/

• Occur when an organism has a key role in the balance of the ecosystem-removal causes changes throughout

the entire ecosystem-can be top down or bottom up-often found after the removal of a top

level predator

• In Minnesota wolves suppress coyote populations, which in turn releases foxes from top-down control by coyote

• The fox then control the intermediate prey species (bunnies and squirrels)

• This allows the competition between the herbivores to produce dynamic equilibrium in populations of herbivores

Remove the top predator• Removal of Wolves releases the coyote• Coyote control more fox• Less fox, more bunnies and squirrels• More bunnies and squirrels, greater

competition between herbivores• Damage to autotrophic levels • Decline of herbivores and then their

predators• Complete ecosystem collapse

http://forestry.usu.edu/htm/video/conferences/rtw-2010/billripple/