Bio 20:Unit 1ABio 20:Unit 1AChapters 1 and 2Chapters 1 and 2

Nelson Pages 6-16Nelson Pages 6-16

The narrow zone around the earth where life exists. Biosphere consists of 3 components:

Lithosphere, Hydrosphere and Atmosphere. Biotic = living organisms (life forms). Abiotic = nonliving component (geological and

physical factors).

• Ecological studies investigate a specific environment by looking at the following:

1.Organism (the individual).

2. Population (group of individuals).

3.Community (1 or more populations).

4.Ecosystem (community and abiotic factors interact).

Composed of 3 regions: Troposphere, Stratosphere and

Mesosphere. 2 outer regions of atmosphere:

Ionosphere and Magnetosphere.Composed of gases:

78% Nitrogen, 21% Oxygen, 0.03% Carbon Dioxide and 1% Argon/other gases.

TASK: Write down the definitions for each of the bolded terms

Smallest living part of an organism

Groups of cells with similar function

Groups of tissues with similar function

Groups of organs with similar function

Groups of organ systems that make up the organism

Group of organisms of same species, living in same area, during same time

Group of different species living in same area

A community and its physical and chemical environment

Large area and its organisms

Narrow zone around Earth with life

Biodiversity = # of species in an ecosystem.

James E. Lovelock: Gaia hypothesis = earth is like 1 living

organism. Dynamic equilibrium = continuous

changes with environments constantly adapting.

What happens when the biodiversity of an ecosystem decreases? Give 1 example (page 9 in text). What effects were there? Why?

A change in any organism level of the ecosystem has extreme consequences.

The species that is most sensitive to changes in an ecosystem is an indicator species.

Amphibians are especially vulnerable. Why?

▪ See page 12 and 13.

•Example: bald eagle as indicator species

•Killed by:

1.) Settlers and farmers

•Threat to livestock

2.) Toxic chemical wastes produced by industries entered food chain

•Egg shells became very thin

•At risk species

•Classified depending on degree of risk

a.) Endangered Endangered

•Species is close to extinction in all parts of the country or in a large location

b.) ExtirpatedExtirpated

•Species no longer exists in one part of the country but can be found in others

b) Equilibrium Unbalanced

c.) ThreatenedThreatened

•Species that is likely to become endangered if factors that make it vulnerable are not reversed

d.) Special concernSpecial concern

•Species at risk due to low or declining numbers at the fringe of its range or in a restricted area

b) Equilibrium Unbalanced

Biosphere 1 = Earth Biosphere 2 = Artificial biosphere created in Arizona - one of

the largest living laboratories in the world An airtight greenhouse that covers 3.15 acres and 7.2 million

cubic feet volume Includes a rainforest, a million gallon salt water ocean, a

coastal fog desert and 4 other wilderness ecosystems The Texas investment company that owns Biosphere 2 north of

Tucson, Arizona is selling the place. Billionaire Ed Bass dropped $200 million in the 1980s to build Biosphere 2 as a prototype "space colony." The experiment suffered major scientific and managerial problems and was eventually opened to the public as a tourist attraction.

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The decline of the wolf: Thousands of wolves died after they ate poisoned bison

carcasses that had been laid out as bait. 1880-90’s: ranchers killed wolves; in Canada anyone

bringing in a wolf skin was paid by the government.▪ Montana = 80 000 wolves were destroyed between

1883-1918. Wolves decline allowed coyotes to increase. Coyotes eat

smaller prey (voles, mice, squirrels, eggs of ground birds); these prey decreased in number.

Wolves left remains of prey; without these remains, scavengers like the magpies, ravens and vultures.

Elk population exploded with no predators; stripping the land of plants. Disease spread rapidly and the population started to decline.

1987- plan to import wolves from Canada to Yellowstone.

35 wolves have been transplanted since 1996; ranchers were opposed to this.

Signs of change: Elk move from open fields to treed areas. Vegetation is recovering. Small predators (kit fox) are increasing population. 5 cows and 53 sheep killed by wolves in Idaho; ranchers

were compensated for losses.

1. Frontier view:1. “to feed ourselves and the hungry world, we must open up,

clear and claim wilderness areas for ranching and other forms of agriculture. Wolves endanger the effort. They kill cattle and sheep. They must be removed wherever they interfere with farming and ranching and they should not be reintroduced once they have been extirpated”.

2. Stewardship view:1. “humans are the most intelligent animals on the planet. It is our duty

to take care of other species and preserve our world. Once we recognize that we have damaged the ecosystem, we must try to repair the damage using whatever resources are available to us. Wolves must be preserved in all ecosystems where they are now found, and reintroduced to ecosystems where they once lived”.

3. Ownership view:1. Canadians do not own wild animals or plants just because they live in

Canada. We have no right to move them around wherever we fell like it. It may have been a mistake to kill the wolves of Yellowstone, but we have no right to take the wolves and move them to a place they haven’t been before. It is better to let the ecosystem in the park find a new balance.”

Nelson Pages 20-37

1. Matter and Energy Relationships

• Matter and energy are essential components of the universe and living organisms.

• Matter - everything that takes up space and has mass

• Energy - the capacity to do work

• the biosphere is composed of a variety of ecosystems

• each ecosystem has a structure based on

a) energy flows

b) matter cycles

Remember Remember this!!!this!!!

Energy Energy Flows, Flows, Matter Matter Cycles!Cycles!

Remember Remember this!!!this!!!

Energy Energy Flows, Flows, Matter Matter Cycles!Cycles!

• An ecosystem = all the organisms living in a community and all the abiotic factors they interact with.

1) Autotroph 1) Autotroph (producers) (producers) • organisms that:

1. get energy from sunlight or nonorganic energy sources.

2. convert inorganic compounds to organic forms.

3. are the basic trophic level in an ecosystem; supports all other organisms

a. Ecosystem Structure

Trophic level Trophic level = category of organisms defined by how they get energy.

Chemosynthesis:•Chemoautotrophs require only carbon dioxide, water and an energy source to make nutrients.

•This energy is emitted from hydrothermal vents near the edges of Earth’s crustal plates.

•Usually found in caves or deep oceans.

•Many animals thrive in the extreme environment around hydrothermal vents.

–Tube worms: survive on energy from bacteria.

2)Heterotroph (consumers) : organisms that derive their energy by consuming other organisms.

a) Primary Consumers

- herbivores (eat only plants)

b) Secondary and Tertiary Consumers

- carnivores (eat other animals)- omnivores (animals which eat both producers and

consumers)

3) Decomposers

- organisms that derive their energy from dead organisms and waste products.

1. Scavengers (eat tissues from dead organisms).

2. Decomposers (feed on detritus).

Why is decomposition important?

Trophic levels

• the steps in the transfer of energy and matter within a community (feeding levels)

• species in an ecosystem are divided into trophic levels on the basis of their main source of nutrition.

• three main types of trophic levels are producers, consumers, and decomposers.

2. Trophic Levels in Ecosystems

Count trophic levels as steps from the original energy source

organization of trophic levels where energy flows from producer to primary and secondary consumers (and others if present)

Simple feeding sequence: who eats who?

Not representative of complex ecological relationships.

Food chain movie

• interconnected food chains within an ecosystem

• highlight the complex, real-world interactions between species

• makes connections from primary producers, through consumers, and back to decomposers

Food Chain Movie

•Most stable ecosystems have complex and well developed food webs the removal of one of its organisms may have little effect

•Where abiotic factors limit the # of organisms, webs begin to look more like food chains

•The lower the biodiversity, the simpler the food web, the more vulnerable each organism is to changes in the ecosystem

The behavior of energy is best explained by the Laws of Thermodynamics.

Where do photosynthesis and cellular respiration fit in? What are they?

3. Laws of Thermodynamics:

a) First Law of Thermodynamics

•Energy cannot be created or destroyed, only changed from one form to another

b) Second Law of Thermodynamics

•With each successive energy transfer, less energy is available to do work. In biological systems, this “waste” energy is often heat.

4. Ecological Pyramids

Because of the loss of energy with trophic levels, there are two consequences for the ecosystem:

1. Because productivity is lower at higher trophic levels, there is less biomass.

2. Lower biomass at higher trophic levels, combined with large body size of top consumers, results in lower population. Densities.

• results in a stepwise decrease in energy (pyramid).

• there are 3 types of pyramids commonly used by ecologists.

Producer

Primary consumer

secondary consumer

tertiary consumer

a) Pyramid of numbers - # of organisms at each trophic level- each bar represents numbers relative to the pyramid base

- pyramids are based on data from a given area eg: 1 km 2

b) Pyramid of Energy - energy stored by each trophic level is given in calories or Joules. Energy per unit area per unit time (Kcal/m2/yr).

Efficiency of energy transferEfficiency of energy transfer::

c) Pyramid of Biomass – stored energy is represented by biomass (dry weight) Biomass per unit area per unit time (g/m2/yr)

•Energy is lost at each step in a food chain or web; the general estimate of this loss at each step is 90%, so only 10% of energy consumed is available to the next trophic level. This is known as the 10% rule.

Photosynthesis and Cellular RespirationPhotosynthesis and Cellular Respiration•Photosynthesis equationPhotosynthesis equation::

CO2 (g) + H2O (l) + energy C6H12O6 (glucose) + O2 (g)

•Cellular respiration equationCellular respiration equation::

C6H12O6 (glucose) + O2 (g) CO2 (g) + H2O (l) + energy (heat and ATP)

•Chemosynthetic Chemosynthetic organismsorganisms::

•Require CO2 (g) + H2O (l) + energy

•Energy required is H2S, NH3, Fe 3+ , S8

Matter is continually entering ecosystems. What if some of the matter entering a food chain was harmful? How would it affect the ecosystem?

Hunting & FishingHunting & Fishing•With introduction of horses into N. America, humans were able to increase hunting of animals, e.g., bison

•Larger nets and an increase in boats have reduced marine fish e.g, cod, halibut, salmon

MonoculturesMonocultures•Biologists estimate 6 to 15 million different species of organisms

•Humans rely on 700 different species of plants

•Wheat, rice, cotton, barley, corn

•Humans tend to use a focused amount of species; useful wild plants have been destroyed to grow food crops

•Negative consequences to using monocultures

•Plants become susceptible to pests and disease

•Plants may lead humans to cures or medicines for diseases but are lost

•Eventually, soils cannot support non – native species of plants

•Barley and wheat are not suited for rich fertile soils found in tropics

•Soils become deficient in their N and P minerals

Have had largest impact on food webs Benefit society

Reduce # of pests (weeds, molds, insects, birds, etc.) to crop production

Reduce spread of disease (malaria, West Nile) Negative consequences to ecosystems:

Eliminating an insect species on small island using DDT reduced spread of malaria, however, entire food web of island was affected▪ Other insects disappeared - then lizards - then cats -

increasing rat population – outbreak of disease = more problems!!!

•Example: DDT accumulation in Peregrine Falcon creates thin shells, therefore breaking easily•Numbers of falcons in Canada decreased so dramatically, that they were close to extinction

•Biological amplification/ magnification• Build up of toxic chemicals in tissues of organisms, as one

moves up food chain• Therefore, the higher the trophic level, the greater the

concentration of toxins

•Negative consequences to pesticides

•“Non – target” species become affected

•Many pesticides are not species – specific

•Affect reproductive ability and embryo development

•Leads to at – risk species

•Moves up the food chain, eventually to humans

1. The term tropic level refers to the position of a species on a food chain (i.e., its feeding level). Producers are at the first trophic level, primary consumers (herbivores) are at the second trophic level, etc.

2. A secondary consumer eats meat, usually primary consumers.

3. A food chain consists of a single path (e.g., algae → zooplankton → minnow → bass → heron), whereas a food web involves several pathways (e.g., algae → zooplankton → minnow → seagull → coyote linked to the chain above).

4. The reactants of photosynthesis are carbon dioxide, water, and energy. The products are oxygen and glucose.

5. The reactants of cellular respiration are oxygen and glucose. The products are carbon dioxide, water, and energy.

6. Inorganic chemicals, such as hydrogen sulphide (H2S), ammonia (NH3), ferrous ions (Fe2+), and sulfur (S8), are used as a source of energy by chemosynthetic bacteria.

7. The first law of thermodynamics states that the total amount of energy in a system remains constant, but it can be transformed into different forms. The second law of thermodynamics indicates that as energy is transformed from one form to another, some of it is lost in unusable forms (such as heat).

8. About 10 % of the energy available in a plant (producer) is transferred to a primary consumer because the plant uses the rest to carry on other processes, such as photosynthesis, growth, and reproduction.

Pages 40-69

Life on Earth depends on recycling of essential chemical elements

Because nutrient circuits involve both biotic and abiotic components of ecosystems, they are also called biogeochemical cycles

Biogeochemical cycles: Water cycle Carbon (oxygen) cycle Nitrogen cycle Phosphorus cycle

Cycling of MatterCycling of Matter•2 processes:

a.) Digestion

•Complex, organic molecules are broken down into simpler molecules

•Become part of body structure

b.) Decay

•Decomposers break down organic matter in dead bodies and feces

•Become part of living world in the future

Why do organisms need water?Water is a polar molecule; because

of this it has interesting properties. Melting and Freezing points. Hydrogen bonds change properties.

Properties of WaterProperties of WaterImportance of Water to Organisms

•Absorbs and releases thermal E and moderates temperature fluctuations•Is the medium in which metabolic reactions occur•Is “universal” solvent•Makes up > 60 % of cell’s mass•Supplies hydrogen atoms to producers during photosynthesis; oxygen atoms to all organisms during cellular respiration•Is a reactant in some metabolic activities and a product in others

Water: A Polar MoleculeWater: A Polar Molecule

•Water molecules are held together by covalent bonds

•Region of “-” charge is created near O atom

•Region of “+” charge is created near H atom

•“-” end of one H2O molecule repels “-” end of another H2O molecule but attracts “+” end

•Attraction of opposite charges creates a hydrogen bond

•Pulls water molecules together

•H bonds explain:

•High melting and boiling points

•More E required to break bonds

Water plays a critical role by: Maintaining global heat balance. Acting as a solvent in reactions.

Movement of water through environment: from atmosphere to earth.

Volume of water remains constant, specific amounts vary in phases; water continuously cycles.

Hydrologic Cycle pg 42-48Hydrologic Cycle pg 42-48Recall – E flows in an ecosystem, matter is recycled - including water

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Water Cycle Animation

Water Cycle Animation 2

Transpiration: Loss of water from plant leaves.

Evaporation: changing from a liquid to gas.

Condensation: changing from a gas to liquid.

Precipitation: snow or rain.Percolation: movement of a liquid

through a porous material (e.g.. Soil).

Leaching: removal of solute by percolation.

Water beneath the Soil• 2 sources of fresh H2O

1. Surface H2O – from precipitation above ground

2. Ground H2O – above ground H2O moves down through soil

• Percolation

• H2O percolates faster through larger soil particles

• H2O eventually fills lower levels of soil (sand and gravel)

• Water table forms above a layer of relatively impermeable bedrock or clay

•Leaching

•Seeping H2O carries dissolved organic matter and minerals to lower layers of soil

•Plants reduce leaching by extending long branch roots deep into soil

Acid rain occurs because of poisonous gases that are released when fossil fuels are burnt.

Gases enter atmosphere, return to earth in rain or snow = acid rain.

acid rain animation

Acid Deposition and the Hydrologic CycleAcid Deposition and the Hydrologic Cycle•Coal - burning plants, metal smelters, and oil refineries release sulfur, during combustion

•Sulfur is released as a poisonous gas, sulfur dioxide (SO2)

•Processing of nitrogen fertilizers, combustion in automobiles, and fossil-fuel burning power plants produce various nitrogen oxides (NOx)

•SO2 and NOx combine with H2O droplets, to form acids in atmosphere

•Acids return to Earth’s surface as snow or rain (acid rain)

•Acid precipitation kills fish, soil bacteria, as well as aquatic and terrestrial plants

•Alkaline soils minimize impact by neutralizing acids before runoff to streams and lakes

•SO2 and NOx can remain airborne, depending on weather conditions

•Dry pollutants can combine with moisture and form acids on lawns, surface of lakes, and respiratory tracts of humans

•Scrubbers have been placed in smokestacks to remove harmful emissions; lime has been added to lakes to neutralize acids; public groups have lobbied for legislative acts

•pH scale is logarithmic, thus, whole numbers represent a 10 - fold change

•pH 5.5 - 5.9 is considered "normal"

•Acid precipitation leaches out (removes) heavy metals (e.g., mercury) in soil and are washed into lakes and rivers

•Affects fish species

•Acid rain reduces productivity of crops and harms vegetation

•Acid surges are periods of short, intense acid deposition in lakes and streams

•Occur during a spring snow melt or a rainfall after a prolonged drought

Role of H2O in Nutrient Cycling

•Carries with it organic matter and nutrients

•Thus, part of nitrogen and phosphate cycles

•Part of carbon and oxygen cycles

•“Capillary action” during transpiration, due to H bond

•Essential in photosynthesis and cellular respiration

Cycling of Carbon and Oxygen. Carbon is a component of all living

and dead organisms; considered organic.

Plants perform Photosynthesis (Carbon dioxide --- glucose) and Animals/Plants perform Cellular respiration (Oxygen --- Carbon dioxide and energy).

Soil organisms (bacteria) decompose dead organisms and return carbon.

The Oxygen Cycle•O2 is an integral part of photosynthesis and cellular respiration

•Cycling of O is part of C cycle

•O produced by plants during photosynthesis atmosphere living things during cellular respiration

•O is also incorporated in the following:

•Ozone (O3)

•CO2

•Rocks

•Decomposition

Oceans store excess CO2

Gas reacts with H2O to form an inorganic compound: calcium carbonate (CaCO3)

Shellfish use (CaCO3) to make their shells Carbon is stored in

shells at bottom of the ocean

Ocean is another carbon sink

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Dead organisms are compressed into fossil fuels; when it is burned, it releases carbon into the atmosphere.

Added Carbon disrupts natural cycling, leading to climate change.

The Greenhouse effect: Carbon Dioxide traps energy in the atmosphere and increases the temperature of the earth.

Greenhouse Effect - animated diagram

•Greenhouse Effect and C Cycle

•Trapping of thermal E is caused by GH effect

•Wavelengths strike Earth’s surface and are reflected in form of long-wave radiation

•Atmospheric gases trap radiation as a blanket of heat

•Since middle of 19th century, human activities have increased concentration of GH gases (25 %)

•Canada is a world leader of world’s total CO2 output, on a per capital basis

•Prediction of an in global temp.’s of 2 to 5OC (global warming)

•Ave. global temp. is 15OC, but has increased by 1 OC in last 40 years

•Melting of polar ice caps could sea level by over 3 meters

•Some regions of world - in rainfall while others,

•Tundra and boreal regions

•Changes in vegetation patterns

•S. prairies may become deserts

•Bogs and muskegs could decay of CH4 gas into atmosphere

Extent that materials reflect sunlight; higher the albedo = more reflection.

Snow, clouds and volcanic ash increase albedo = increase reflection/decrease temperature (nuclear winter).

The levels of carbon and oxygen can be determined using stromatolites- limestone rock with fossilized bacteria.

Originally methane levels were higher, creating a haze around the planet that deflected the sun and allowed more temperate conditions on earth.

Includes 4 Processes: Nitrogen fixation, ammonification, nitrification and denitrification.

Nitrogen is an important component of all proteins and nucleic acids.

Most organisms can’t use Nitrogen directly; it must be put into soli by: Volcanic action. Lightening. Nitrogen- fixing bacteria.

Nitrogen fixation: bacteria (90%)/lightening (10%) convert atmospheric nitrogen into roots of plants (legumes).

Fertilizers increase this amount.Ammonification: Decomposers

convert nitrogen products (from tissues) into ammonia (NH3).

Nitrification: process changing ammonium ions into nitrates (NO3), performed by nitrifying bacteria.

Absorbed by plants, used to make a.a’s: absorbed by consumer when eaten.

Denitrification: Bacteria convert ammonia into Nitrogen, which returns to atmosphere.

fertilizer - chemicals that contain nitrogen and phosphorus natural fertilizer

Manure: contains N which is ammonified first in the soil, then nitrified to provide useful nitrates

Commercial Fertilizers: 3 numbers: The first number is the % nitrogen (by

weight) The second number is the % phosphorus

(by weight) The third number is the % potassium (by

weight).

Agriculture and the Nitrogen and Agriculture and the Nitrogen and Phosphorus cycles:Phosphorus cycles:Fertilizer - chemicals that contain nitrogen and phosphorus natural fertilizerManure; contains N which is ammonified first in soil, then nitrified to provide useful nitratesCommercial Fertilizers:

First # is % nitrogen (by weight) Second # is the % phosphorus (by weight) Third # is the % potassium (by weight)

Found in ATP, cell membranes and animal bones.

Phosphate is found in rock (reservoir); phosphorus leeches out into the water table.

Is a limiting factor in terrestrial and aquatic ecosystems (Phosphorous isn’t useable).

As Phosphorous becomes available, it is quickly taken up.

Phosphates remain in the Soil Phosphates Washed into the Ocean

FAST TRACK…FAST TRACK… SLOW TRACK…SLOW TRACK…

Animals eat plants to obtain P

P returned to soil

Decomposers work to and plants break down animals

P becomes part of shellfish

Shellfish die and P settles in sediment

Over millions of years, this sediment is pressed into rock that is thrust upward

Phosphorus Cycle

Agriculture and Nutrient Cycles•Harvesting of crops removes N and P from soil

•Interrupts natural cycles

•Fertilizing soil restores nutrients and increases food production

•Irresponsible fertilizing can produce soil that is 10 X more acidic

•Destruction of crops as well as acid deposition

•Eutrophication and Algal Blooms•Spring runoff of N and P, from fertilized soils, into lakes promotes aquatic growth (blooms) which decreases O2 levels in lakes decomposing bacteria use O2 lake O2 levels decrease and fish begin to die

Algae Bloom – prevent light from reaching bottom of lake or pond

•Nitrites in drinking water

•Adult humans and animals have bacteria in large intestines to convert NO3 1- into NO2 1-

•Bacteria cannot live in human stomach

•However, in young humans, bacteria can travel from large intestines to stomach (less acidic)

•Convert NO3 1- into NO2 1-

•Can attach to hemoglobin of blood, thus, less O2 in body

Complete the N-cycle worksheet (workbook)

Label and color N-cycle and P-Cycle coloring book diagram

Section 3.3 Questions page 66 Text

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Review N and C CyclesReview N and C Cycles

Review nitrogen cycle Review nitrogen cycle

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http://www.nslc.wustl.edu/courses/Bio381/movies/processes/C&Ncycles

An ecotone = transition area between ecosystems.

Each organism has a niche = it’s role in the ecosystem (place in food web, habitat, breeding area).

Niches help reduce competition for resources and stabilize the ecosystem.

Why does an exotic species cause disruption?

Ecological niche benefits:

•Helps reduce competition between species

•Ex: owls and hawks

•Different time of day to hunt

•Different adaptations to habitat (grassland vs. forest)

•Different nesting sites

•Ex: different species of warblers prefer a different section of trees

Competition for Niches

•New or “exotic” species that enters an ecosystem causes a disturbance

•They compete with one or more species “indigenous” to an area

•How are species introduced?

•Animals move

•Plant seeds are carried by wind or animals

Introduction of Exotic Species

•Human introduction of species causes species extinction (2nd to habitat loss)

•Reason:

•Ecosystem may lack natural predators or diseases

•Many types of prey available

•Settle in nesting sites before indigenous species

•Examples: starlings, purple loosestrife, thistle

1) Interactions within Ecosystems

Nelson pages 86 – 93

•Ecologists study interactions between biotic and abiotic factors

•Study how biosphere operates by investigating various levels of organization

Organism (biologist)

Biosphere (ecologist)

Cell Organism

Tissue Population

Organ Community

Organ system Ecosystem

Complete organism Biosphere

There are 4 biomes in Canada, each with abiotic and biotic factors:a.Tundra/Muskeg:

- abiotic- arctic, short growing season, permafrost layer, low temperatures, low precipitation.- biotic: caribou, mosses/lichens, polar bears, seals, rapidly flowering plants.

Abiotic: south of tundra, 35-40cm/year precipitation, change in weather patterns, acidic, watery soil.

Biotic: Coniferous forest, moose, Goldenrod, caribou.

Abiotic: South of boreal, increased sunlight, precipitation (100 cm/year), rich, fertile soil.

Biotic: Deciduous trees, moose, weasels, many shrubs, woodpeckers.

Abiotic: Same latitude as mixed woodland, less precipitation than woodland, soils holds more water.

Biotic: Hawks, rattlesnakes, Plains bison.

Abiotic factors are non-living components of an ecosystem Affect type and # of organisms that can live there

Describe abiotic components that cause the two terrestrial ecosystems below

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Abiotic factors are called limiting factorsWhy?

They restrict or limit # and types of organisms able to survive in a particular environment

Belts of climate determine result in distinct vegetation patterns

Vegetation of a region determines which consumers can and will continue to exist there

Zones are called biomes

Physical features of a geographical areaa) Latitude - higher latitudes: less solar energy input, varied

day lengths with seasonsb) Altitude - higher altitudes: cooler temps, more wind, poorer

soilc) Topography - physical features of land (ex: mountains,

river valleys)▪ May affect precipitation

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a) Terrestrial (land) abiotic factors: 1. Soil: Known as Edaphic factors.

- 4 layers: Litter (partially decomposed matter), Topsoil (rock and humus), Subsoil (lighter color and less organic material) and bedrock (layer beneath the soil).- pH of soil determined by plants and rock that forms is; basic = alkaline or acidic.

2. Available water: determined by amount and type of precipitation.- groundwater = precipitation that stays in the soil, determines depth of water table.

3. Temperature: can vary greatly- dependant on climate.- organisms adapt to temperature changes; examples?

4. Sunlight: varies with altitude and latitude.

Ecosystem Type of SoilTaiga •Well – drained,

acidicMuskeg •Poor drainage

and low amounts of O2

1) Chemical environment – type of water, dissolved oxygen, pH.

2) Temperature/Light – varies with seasons and water depth.3) Water Pressure – adapted to live near surface or at greater

depths.

1. Oxygen Lakes and ponds get some O2

from atmosphere, but most from photosynthetic plants

Fast flowing rivers get major source of O2 from aeration

Lowest acceptable limit is 5 ppm (5 parts of O2 per million parts water)

Conc. of O2 in water decreases as temperature increases

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2. Carbon Dioxide Respiration by living organisms is major source Surface contains very little but bottom has

higher levels due to respiration by decomposers; mostly bacteria

3. pH Healthy range is usually between 6.7 to 8.6 Acid rain can cause pH levels to drop, making

aquatic environment unable to support life

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4. TemperatureEach species has a preferred temp.With most species, an increase by 5OC is harmfulAs water temp goes up, ability to hold O2 goes down, yet animal needs more O2 --------> or dies5. LightIncreased light means increased P/S and higher plant productivity6. Water PressureWater is 800 X denser than airPressure increases by 100 kPa for every 10 m of depthAve. depth of ocean is 4000 m

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Read pages 99-100 and make notes: define the 3 general zones of lakes, describe the typical biota of the zone and abiotic factors of the zone, define epilimnion, hypolimnion, thermocline (see index).

Lakes during the Winter•Temp. of ice is slightly above 00C ; light can penetrate transparent ice for Ps to occur

Lakes during Spring•O2 becomes dissolved from air

•Winds and storms increase rate of dissolved O2 oxygen

•As temp. of surface water approaches 40C, it sinks through less dense water

•Carries O2 throughout all depths

•Process is spring overturn

Bogs are usually located in regions where temp.’s are cool for much of year

Marshes and swamps are usually located near coastal areas in warmer climates

A variety of waterfowl and shore birds live in swamps and marshes

• Also provide shelter to animals

▪ Muskrats, frogs, turtles, snakes, alligators, fish, and raccoons

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Type of Vegetation

Marshes Swamps •Small plants

•Reeds, cattails, and grasses

•Large plants•Cypress trees and Spanish moss, as well as shrubs and water lilies

Bogs• Large # of insects

• Beetles, dragonflies, and mosquitoes, are common in bogs

• Bogs also have a variety of plants that grow well in the organically rich, partially decayed plant material called peat

• Peat forms much of bog soil

• One of the most unusual bog plants is the pitcher plant

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Pages 108-112

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Field mice can reproduce every 6 weeks and can have litters of 6 or more. A population of 20 mice could become 5120 mice in six months! What factors prevent a population explosion of mice?

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Biotic potential is maximum # of offspring that a species could produce if resources are unlimitedRegulated by 4 factors:

Birth potential (max #/birth)Capacity for survival (# reach reproductive age)Breeding frequencyLength of reproductive life (age of sexual maturity and # of fertile years)

Limiting factors are factors that restrict or limit # and types of organisms able to survive in a particular environment Prevent populations from obtaining their biotic potential

Carrying capacity is maximum # of individuals that can be supported by an ecosystem

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At what level do the deer reach their CARRYING CAPACITY?

Factors that causes a population to increase

Factors that cause a population to decrease

Abiotic •Favorable light, temp., chemical env.

•Too much or too little light, too cold or too warm, unfavorable chemical env.

Biotic •Sufficient food, low # or low effectiveness of predators, few or weak diseases and parasites, ability to compete for resources

•Insufficient food, high # or high effectiveness of predators, many or strong diseases and parasites, inability to compete successfully for resources

Law of Minimum – The nutrient that is in

least supply is the one that limits growth (proposed by Justus von Liebig (mid1850’s)

Victor Shelford (1913) added on to the Law of minimum by proposing the Law of Tolerance An organism can survive

within a particular range of an abiotic factor

Density-Independent factors affect a population regardless of population density

Density-Dependent Factors affect size of a population as a result of population density

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Factors that Cause Changes in Populations

Density – independent factors

Density – dependent factors

•Flood•Fire•Pesticides•Change in climate or temp.•Destruction of habitat•Drought

•Food shortage•Competition for mates, breeding areas (habitat)•Disease caused by a microorganism or parasite•Introduction of an exotic species•Increased predation•Competition for water and other resources

Pages 113 -122 Nelson

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I. Changes in Terrestrial Ecosystems

•33 % of Earth’s forests have been cleared for agricultural or urban land purposes

•Significance of forests:

•Recycle H2O and CO2

•Thus, affect climate

•Affect physical environment

•Control H2O runoff, hold groundwater, and prevent soil erosion

•Provide shelters and nesting sites for wildlife, as well as food

Forestry Practices

• 3 categories of deforestation:

1. Slash and burn

• Used in tropical areas

• Agriculture

• Vegetation is bulldozed and burned in a pile

2. Clear – cutting

• Removal of all trees in an area for use in timber or pulp

• Followed by replanting the dominant species

Forestry Practices

3. Selective cutting

• Only certain trees are harvested from an area

• Other trees are left to regenerate the area

• Softwoods (spruce and fir) are considered more valuable than hardwoods (grow slowly)

• 2 – 3 years after cutting, herbicides are used to prevent softwoods from being overcrowded by hardwoods

• 10 years – underbrush is removed

• 35 years – trees are checked for diseases, as monocultures are more susceptible

• 80 – 90 years, softwoods can be harvested

Effects of Clear - Cutting

Positive Effects Negative Effects

•Less expensive than selective cutting•If pests exists in an area, this method eliminates pests without infecting surrounding areas•Permits replacement of less valuable trees with ones more valuable•Moose benefits; fruit – bearing shrubs provide stable food source

•Soil erosion and runoff into streams increase•NO3

1- and other nutrients increase algal growth in streams•Sediment carried into streams affect fish spawning•Dark soils are exposed; water loss of soils increases•Replanting with a monoculture decreases biodiversity•Owls are negatively affected; nesting sites are destroyed

2) Effects of Fire

•Fires in Elk Island National Park

•Create and maintain a mosaic of vegetation types

•Prescribed burns

•Fires set intentionally in defined areas of a park

•Fire is carefully put out

•Reduces amount of dry timber

•Discourages expansion of forests and maintains food supply for bison

E) Ecological Succession Process of Succession

•Ecological succession - a community change in which new populations of organisms gradually replace existing ones

• Succession occurs from natural causes (competition, fire, earthquakes, etc) or due to humans (logging, mining, farming etc)

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1) Primary Succession• Succession that begins in an area where there is no existing

community

• Causes: volcanic eruption, glacier retreat

• Pioneer community: 1st group of organisms to occupy an area undergoing

• Pioneer organisms must be hardy and able to live on minimal resources

• Lichens are pioneer organisms

Primary Succession Animation

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Soil formation (lichens die/ break up rock)

Soil formation (lichens die/ break up rock)

Glacier Retreats exposing Parent rock

Glacier Retreats exposing Parent rock

Pioneer community (lichens, mosses)

Pioneer community (lichens, mosses)

Enough soil = grasses out compete lichens

Enough soil = grasses out compete lichens

Grasses die = more soil = shrubs and weeds take over

Grasses die = more soil = shrubs and weeds take over

Increased soil = shallow rooted trees (pine)

Increased soil = shallow rooted trees (pine)

Increased pine = more shade = favorable for deeply rooted plant (maple/ birch)

Increased pine = more shade = favorable for deeply rooted plant (maple/ birch)

Climax CommunityClimax Community

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Primary Succession:Primary Succession:

Primary Succession Animation

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2) Secondary Succession•Occurs in an area where an existing community has been partially destroyed

• Examples: Fires, logging, farming

•Occurs more rapidly than primary succession

•Climax community

• A community that achieves relative stability

• Tend to have greater species diversity than the communities that precede them

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1. Indicator (index) Species When water becomes polluted, there tends

to be a shift from MANY species of moderate population density to a FEW species of high population density ------> indicator species

This decrease in diversity of species present is best indicator of pollution

2. Eutrophication Natural process of SLOWLY aging or

increasing productivity of a body of water

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Pollution increases the natural eutrophication process of water. Why?

Unnatural Eutrophication: a process in which nutrient runoff from agricultural lands or livestock operations causes photosynthetic organisms in ponds and lakes to multiply rapidly

Human-caused eutrophication wiped out fisheries in Lake Erie in the 1950s and 1960s

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High levels of P and N containing compounds (fertilizers/ detergents)

High levels of P and N containing compounds (fertilizers/ detergents)

Algal BloomAlgal Bloom

LAKE EUTROPHICATIONLAKE EUTROPHICATION Algae die =

food for decomposers = population grows

Algae die = food for decomposers = population grows

Decomposers break down material and use up oxygen in lake

Decomposers break down material and use up oxygen in lake

Low oxygen = other organisms die out

Low oxygen = other organisms die out• Water in which oxygen becomes too low to support animal life is

called eutrophic

• To protect Canadian lakes, ponds, and streams from becoming eutrophic, some provinces no longer allow the sale of detergents containing phosphorus compounds

Eutrophic vs. Oligotrophic Lakes:• Classification of lakes by the nutrient input, which in turn determines

primary producers --- 2 types:• Oligotrophic lakes: Nutrient-poor, photosynthesis-limited, clear water,

O2 rich, deeper and colder than eutrophic lakes• Eutrophic lakes: Nutrient-rich, high photosynthesis, murky water, O2

poor.

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•Eutrophication of a lake depends on natural and human factors:

•From oligotrophic to eutrophic

a.) Oligotrophic – deep, cool, hold a lot of O2

b.) Soil sediment and organic material fall to lake bottom

• Lake becomes shallow profundal zone disappears sunlight reaches lake bed

•Water temp. and plant growth increase, O2 levels drop, which reduces # of aquatic animals

c.) Lake continues to become shallower and warmer

•More matter and nutrients accumulate

•Submerged and emergent plants accumulate

•Too many producers and decomposers deprive lake with O2

•Reduces # of fish spp. (e.g., trout and salmon)

•Plankton, insect larvae, worms, leeches, and mollusks thrive

•Slug worms are indicator spp. of aquatic ecosystems to identify lakes with lower levels of oxygen

3) Sources of Water Pollution•Organic solid waste

•Includes sewage and waste from food processing

•Decomposed by bacteria, which uses up O2

•Disease – causing organisms

•From sewage and animal wastes that runoff into aquatic ecosystems

•Trigger water – borne diseases (ex: typhoid)

•Inorganic solids and dissolved nutrients

•Waste from mining, fertilizers, salts from roads and runoff

•Thermal energy

•From electricity generating plants and other industries

•Decreases solubility of O2 in water

•Organic compounds

•Oil from roads, pesticides, and detergents (organic phosphates)

•Toxic, accumulate through food chain, promote algal bloom, respectively

4) Indicators of Water Quality• 3 main indicators

1.Bacteria count• Detect coliform bacteria

• Found in intestines of humans and other animals

• Presence indicates fecal contamination in water

• Process:

• Agar medium, with nutrients, is used to grow bacteria

• The greater the # of bacteria colonies, the more polluted the water sample

2.Dissolved Oxygen• Solutions can be used to test for D.O.

• Change color when they react with oxygen

• Cool lakes, with few pollutants have a D.O. of 8 – 14 mg/L

• Examine living things in the water

• Healthy trout – high oxygen level

• Carp and catfish – low level

• Absence of fish – low oxygen level; possible toxins in the water

3.Biological Oxygen Demand• A measure of amount of dissolved O2 needed by

decomposers to break down organic matter in a sample of water over a 5 day period at 20 OC

• Cold, less productive lakes

• BOD near 2 mg of O2/L

• Warm, more productive lakes

• BOD near 20 mg of O2/L

• As # of organisms , BOD increases, more organisms use O2, thus, DO

• Humans releasing sewage or nutrients promotes algal bloom, which decaying matter, which decomposition

4) Changes in Alberta’s Lakes•Receding shore lines

•Changes in water shed

•Area of land that drains towards a lake or body of water

•Drop in lake levels

•Increase in salinity

•Reduced O2 levels and biodiversity

•Increase in erosion at shoreline

•Eutrophication by sewage, phosphorus, and fertilizer runoff

•Change in odor and taste of water