unit 3 ecosystems - wvhs.k12.nf.ca · unit 3 ecosystems geog 3202 ... the tertiary consumers would...

Unit 3 Ecosystems Geog 3202

Chapter 6 & 7

* Many of the diagrams referred to in this presentation have been

scanned from the text book.

Define the terms ecosystem.

trophic level.

food pyramid

organisms

pesticides

producer

consumers

decomposer

herbivore

carnivore

Tundra

Forest

Grassland

Desert

soil texture.

Humus

Loam

Clay

Silt

Sand

Climax vegetation

Drought

Degradation

Desertification

Deforestation

Ecosystems of the World: Tundra

Ecosystems of the World: Forests

Ecosystems of the World: Grasslands

Ecosystems of the World:

Mountains


Deserts


Marine

7 Natural Vegetation Zones in Canada

(Refer to p.70, Text)

REMEMBER!!!

Strong relationship between climate

and the location of an ecosystem:

precipitation and temperatures.

In Canada, ecosystems are greatly influenced by

temperatures and precipitation, which in turn are

affected by latitude.

Generally, Canada is classified as a Nordic (northern)

climate - cold climate.

While summers are generally warm and at times hot,

they are all too short.

Winters on the other hand can be long and cold.

These conditions are also directly related to wet and

dry conditions which can affect soil fertility - hence

inability to produce vegetation.

Outline the flow of Energy through an ecosystem P. 95

Tree → insect → insect eating bird → hawkProducer Primary consumer 2nd order consumer 3rd order consumer

Note; The arrows indicate the flow of energy & nutrients

Draw an example of a food web containing humans. P. 94

ManCow

Mosquito

Hawk

Phytoplankton

fish

Grass Decomposer

3.1.3 Using figure 6.5 summarize the main energy flows in an

ecosystem p. 95 Sun = source of all ecosystem

energy

Producers make food via photosynthesis

Consumers eat plants and other consumers to get energy

Each time energy moves from one organism to another, energy leaves the system in the form of heat.

Decomposers return nutrients to the soil but energy is not recycled.

Unit 3 Part 2

Food Pyramids p. 95-100

Pyramid of Energy:

There is a high degree of energy loss at each trophic level.

◦ The producers only store 1% of the sun's energy as food energy.

◦ Each consumer level loses energy for several reasons:

much of the energy is lost as heat;

most of the energy is used to carry out life functions—ie. we

burn many calories of energy each day, so do all organisms;

if an organism dies without being eaten the energy goes to the

decomposers and not up the trophic levels;

consequently only about 10-15% of the energy is stored as usable

food energy at each level..

Pyramid of Energy:

If we look at this in terms of units of energy and we start

with 1000 units of energy at the producer level then:

the primary consumers would only have 100-150 units

of food energy stored for the next level;

the secondary consumers would only have 10-15 units

of food energy stored for the next trophic level;

the tertiary consumers would only have 1-1.5 units of

food energy stored as food energy—it is easy to see

why we do not often see a quaternary trophic level

Why are there fewer organisms at each

trophic level? P. 97

Less energy available at each level

Fewer organisms can obtain energy to live

Therefore fewer organisms at increasing levels

Only a fraction of the energy available at one trophic level is transferred to the next trophic level. The rule of thumb is 10%, this is very approximate.

Typically the numbers and biomass of organisms decrease as one ascends the food chain.

Farmer question about energy efficiency P. 97

a. Wheat would be far more efficient

than cattle.

b. Wheat is a producer and producers

contain more energy than primary

consumers (like cows) as is seen in

the food pyramid. The energy flow

diagram shows that each trophic

level loses energy as heat.

c. Farmers would have many other real

concerns. Price, growing conditions,

markets etc.

3.2.1 How do food pyramids help explain DDT Bioamplification?

This problem has occurred in our environment.

The most common case was that of DDT which

was used to control insect populations

DDT was a particularly dangerous toxin because it

is fat soluble and stays in an animals fat. (Some

poisons are water soluble and can be excreted from

the system)

Bioaccumulation

Some pesticides were fat soluble which lead to a problem known as bioaccumulation.

As each organism feeds on one lower in the food chain, the fat soluble pesticide began to be concentrated in ever higher amounts as you movetoward the top of the food pyramid.

Biomagnifcation results from bioaccumulation

3.2.1 How do food pyramids help explain DDT Bioamplification?

Lower order organisms ingest some

poison which may or may not affect

them.

Higher order organisms eat large

numbers of lower order organisms.

A small amount of toxin in a frog

becomes a large amount in a hawk that

eats 100 frogs.

Since every organism eats far more than its own body mass in food, the tiny amounts found in each organism consumed began to build up in greater concentrations in the consuming species

This is illustrated by the damage done to predatory birds as a result of bioaccumulation of DDT.

As a result DDT has been banned from use in North America.

Climax Vegetation is the natural vegetation in

the last possible stage of vegetation

development.

• Climax vegetation is stable and in balance

with the climatic conditions.

• It should change very little if left undisturbed.

The vegetation that would exist in an area if growth had

proceeded undisturbed for an extended period. This would be

the "final" collection of plant types that presumably would

remain forever, or until the stable conditions were somehow

disturbed.

• Ecosystems are largely defined by the climax

vegetation that grows in it.

The type of vegetation is largely determined by the

climate.

• We will look at three major type of ecosystems

found in high latitude regions.

Look at figure 6.8 on page 102 of your text book

and you will see the variety of ecosystems in

the world.

3.3.1 Continued (Ecosystem climatic conditions p.104)

Boreal Forest

Temperate cold winter

climate

Warm summers

Moderate precipitation

Beaverlodge, Alberta, Canada

earthobservatory.nasa.gov

Boreal Forest (Taiga)

Average annual temperature

and precipitation

55oN; 119o W

http://earthobservatory.nasa.gov/Laboratory/Biome/mapconiferous.html

http://earthobservatory.nasa.gov/Laboratory/Biome/mapconiferous.html

Describe “climax vegetation” in coniferous forest. P. 102

Evergreen trees

Needle like leaves

Thick bark

Conical shape

Dense growing which

blocks sun

Coniferous forests

The location of the Boreal forest can be seen by

analyzing the world ecosystem map (figure 6.8) on

page 102.

It is found only in the northern hemisphere and is

located in a broad band across Northern North

America and Northern Eurasia.

Coniferous trees are well adapted to lack of water

in winter (it is all frozen)

Needle leaves reduce surface area for transpiration

Drooping branches and conical shape allow heavy

snow to fall off relieving the pressure

Thick bark reduces water loss.

The climate in the boreal forest is temperate

cold winter.

Look at figure 6.8 on page 102 and locate the

boreal forest; then turn to page 75 and locate

the temperate cold winter (subarctic)

climate region. the two match very closely.

3.3.1 Ecosystem climatic conditions p.104

Tundra

Polar – sub arctic climate

Short summers

Avg. monthly temp. always below 10oC

Very cold long winter

Light precipitation

Yakutsk, RussiaLocation:

62.1 N; 129 W


Average annual temperature

and precipitation

http://earthobservatory.nasa.gov/Laboratory/Biome/maptundra.html

http://earthobservatory.nasa.gov/Laboratory/Biome/maptundra.html

The “climax vegetation” in the Tundra is:

grasses, shrubs and low plants with

◦ Shallow roots

◦ Fast reproduction/flowering cycle

See ecosystem map (figure 6.8) on page 102.

Compare p102, and p75 the two match very

closely.

It is found only in the northern hemisphere and is

located north of the Boreal forest

The shrubs and bushes are well adapted to the

extreme climate (winter is long and summer is

very short. )

Shallow roots are needed because 1-3 meters

below the surface the soil is completely frozen

(Permafrost).

The fast flowering and reproduction cycle is needed

because the growing season is very short, lasting

only 1-2 months.

Animals have a variety of adaptations to the harsh

Tundra climate;

◦ Hibernation

◦ Migration in for the summer season and out for the

winter .

◦ The development of insulating features like thick fur & fat

insulation

Polar Ice Caps

The “climax vegetation” is Phytoplankton beneath the

ice

The adaptation of producers to this ecosystem is

extreme.

There is no land for the producers to grow in so

there are only small phytoplankton to form the base

of the food chain. .

Polar Ice Caps

Polar Ice Caps

Animals have a variety of adaptations to

the harsh Polar ice cap climate.

Migration in for the summer season and

out for the winter season is a common

strategy for Birds and even larger animals

like caribou.

Polar Ice Caps

The development of insulating features like

thick fur & fat insulation is common among

polar bears and other mammals.

White fur/feathers to help with camouflage is

another common adaptation.

The climate in the Polar ice cap is so definitive

of the Polar ice cap that it is called Polar (ice

cap) climate.

Compare p102, and p75 the two match very

closely.


Temperate Grassland

Semi-arid climate or temperate cold

winter

Light precipitation, most of it occurs in

summer

Warm to hot summer

Cold winters

Ingeniera White, Argentina40oS; 6oW


Average annual temperature and rainfall

The “climax vegetation” is grass with shallow roots,

small water requirement

See world ecosystem map (figure 6.8) on page 102. It

is found in North America, South America, Australia

and Eurasia.

Grasses are well adapted to lack of water; the small

size of the plant

The climate is semi-arid in most locations but in

some regions it is temperate cold winter.

Compare p102, and p75

The climate in the Temperate grassland

is semi-arid in most locations but in

some regions it is temperate cold winter.

Look at figure 6.8 on page 102 and

locate the Temperate grassland; then

turn to page 75 and locate the semiarid

climate region.

The two match very closely.


Temperate Forest

Temperate Mild winter climate

Warm – hot summers

Moderate - heavy precipitation

Staunton, Virginia, United States38oN; 79oW


Average annual temperature and rainfall

http://earthobservatory.nasa.gov/Laboratory/Biome/maptemperate.html

http://earthobservatory.nasa.gov/Laboratory/Biome/maptemperate.html

The “climax vegetation” in Temperate forests is:

deciduous trees like oak, birch and maple which lose

leaves in winter

Deciduous trees are well adapted to lack of water in

winter.

Losing their leaves in winter helps them reduce water

loss.

The climate in the Temperate Forest is temperate

mild winter.


The climate in the Temperate Forest is temperate

mild winter.


Temperate forests; then turn to page 75 and locate

the temperate mild winter climate region.



Tropical Rain Forest

Tropical Wet climate

High temperatures year round

High precipitation year round

Campa Pita, Belize

15 N latitude


Tropical Forest

Average annual temperature and precipitation

Tropical Rain Forests The “climax vegetation” is tall Evergreen Broadleaf

trees, these are well adapted to the thin soil with

buttress roots (figure 6.15 on p 108) to help support

their height.

Some plants are epiphytes which are well adapted to

the rain forest.

They reach the sun by lying in the canopy while they

get water through roots that hang in the air and

absorb moisture.

Some animals are adapted to spend their entire life in

the canopy.

The climate in the Tropical rain forest is Tropical wet in

most locations but in some regions it is tropical wet

and dry.

mostly concentrated in two bands around the earth

10-30 North and South of the equator

The climate in the Tropical rain forest is Tropical wet

in most locations but in some regions it is tropical

wet and dry.

Look at figure 6.8 on page 102 and locate the Tropical

rain forest; then turn to page 75 and locate the

tropical wet climate region. The two match very

closely.


Savanna

Tropical wet & Dry to semi-

arid climate

High temperatures most of

the year

Light to Moderate

precipitation usually all in

one season

savanna

The “climax vegetation” is grass with shallow roots,

small water requirement

◦ Grasses are well adapted to lack of water.

◦ The small size of the plant means that it requires less water.

See world ecosystem map (figure 6.8) on page 102,

compare with p 75.

South America, Australia, Africa and Southeast Asia.

Climate is tropical wet & dry in most locations but in

some regions it is semi-arid .


Savannas; then turn to page 75 and locate the Tropical

Wet and dry climate region.

The two match very closely


Desert

Arid climate

High temperatures year

round

little precipitation

Deserts

The “climax vegetation” is: Cacti and

fleshy plants Cacti are well adapted to

lack of water.

They are often referred to as Xerophytes.

long roots help them obtain water deep

in the water table

water storage capacity gives them the

ability to endure long periods without

rain.

Deserts

leaves modified as needles reduces the

surface area for transpiration and helps

reduce grazing which would severely

increase water loss.

mostly concentrated in two bands around

the earth 30 North and South of the

equator


El-Oasr el-Akhdar, Egypt26oS; 30oE

Average yearly temperature and rainfall

The climate in the Desert is Arid.


Deserts; then turn to page 75 and locate the arid

climate region.


Mountain Ecosystems

Mountains ecosystems are not exclusively low

latitude, on the contrary they occur in most latitudes

and as you will see in figure 6.10 (p104) mountains

can contain all types of ecosystems from all latitudes.

Figure 6.10 well illustrates the fact that latitudinal

succession closely parallels altitudinal succession.


Mountain

Different climates at

different elevations

High elevations often like

tundra

The changes we see in ecosystems as we move north

from the equator are generally, tropical rain forest,

Temperate forest, Coniferous forest, shrubby tundra

and then polar ice cap.

The same changes in ecosystem can be seen as you

move up a tropical mountain.

Mountain ecosystems are not very unique, they vary

with altitude and temperature.

Analyze world ecosystem map.

a. Boreal Forest & tundra are

wide spread in high latitudes

b. Tropical Rain Forests occur in

low latitudes

c. Tropical Rain forest is most

predominant in South America.

d. South America, Africa, Australia

and Antarctica do not have

tundra.

e. Boreal forest is our ecosystem

3.3.2 Ecosystems vs. climatic regions p.104

• Ecosystems of the world are largely defined by their climax vegetation.

• Example: tropical rain forest, grasslands, boreal forests, etc.

• Climax Vegetation is determined by climate. Therefore, ecosystems parallel climate zonesClimate zones

Ecosystem

zones

. Continued (Ecosystems vs. climatic regions p.104)

Arid gives Desert

Semi-Arid gives

Grassland

Tropical Wet gives

Tropical Rain forest

Temperate cold winter

gives Boreal Forest

Temp. mild winter gives Temp.

deciduous Forest

World Ecosystems

Different Locations

Different Climate (Temp. & Precip.)

Different Soil

Different Vegetation

Different Animals

Ecosystems

Climate Zones

Climate zones

Ecosystems

Ecosystem climatic conditions p.104Tundra

Polar – sub arctic climate

Short summers

Avg. minthly temp. always below 10oC

Very cold long winter

Light precipitation

Succession: Directional cumulative change in the

types plant species that occupy a given area, through

time.

Relationship between Ecosystems and Latitude

The further north you travel the colder

and drier it gets thus less vegetation.

Winters are longer (colder) and summers

are shorter (less heat).


Mountains are the exception because

elevation/altitude determines the type of

vegetation.

The higher you rise on the land the colder

and drier it will be thus vegetation will

change.

Climate controls biome distribution by an altitudinal

gradient and a latitudinal gradient.

With increases of either altitude or latitude, cooler and

drier conditions occur.

Cooler conditions can cause aridity since cooler air can

hold less water vapor than can warmer air.

This is shown by the figure

Altitudinal succession vs. latitudinal succession p. 104

Altitudinal succession vs. latitudinal succession

The changes in ecosystems & vegetation that occur as one moves from the equator to the poles


The changes in ecosystems & vegetation that occur as one moves from the base of an tropical mountain to the summit.



The changes in ecosystems & vegetation that occur as one moves from the equator to the poles is very similar to the changes in ecosystems &

vegetation seen moving from the base of an tropical mountain to the summit.


3.3.2 Altitudinal succession vs. latitudinal succession p. 104

The changes in ecosystems that occur as one moves from the equator to the poles is very similar to the changes in ecosystems seen moving from the base of an tropical mountain to the summit.

Identify the ecosystems where the threat of

desertification is greatest and describe the underlying

causes

Deforestation contributes to the removal of nutrients

from the soil and exposes more land to erosion.

These directly contribute to desertification and as

such, it can be considered an indicator of possible

risks of desertification.

The following map shows the areas experiencing

deforestation as well as land degradation in drylands.

Areas in Asia are experiencing both net loss of forests

as well as land degradation.

In many of these areas, the two drylands and forests

are located fairly close to each other which allows for

desertification to spread more quickly.

The areas shown on this map that are experiencing

deforestation are all more likely to be subjected to

desertification at a faster rate than they would be

without the removal of the forests.

Desertification

Desertification

Desertification-is the process by which land becomes desert

Drought and overpopulation are main causes

Signs

Lowering of water table

Marked reduction of water supply

Progressive destruction of native vegetation

Accelerated soil erosion

Case Study: The Sahel

The Sahel is becoming

more like desert with

thin, dry, sandy soils

Soil erosion has created

bare rock

Vegetation is sparse

Desertification- Map of the Sahel

Each of these factors has contributed to

desertification

desertification

climate humans animals

Climate

Drought: low rainfall since 1968.

Soils become dry and there is no water left in wells.

Trees die, grass withers and is replaced by poor desert scrub.

Crops fail and cattle feed on poor pasture.

Less roots to protect the topsoil, less humus; soils become more sandy and dry.

Wind erosion removes the soil, causing dust storms, leaving bare rock.

Human activity Population is high and increasing fast.

To increase food supplies more crops are grown and more cattle kept leading to over-cultivation and over-grazing.

Yields decline and cattle are undernourished and die.

Demand increases for water as population grows.

Trees are cut down for fuel supplies.

Less vegetation; more dry, bare soil; more wind erosion.

Animals/insects

Locusts destroy the crops.

Overgrazing means all vegetation is eaten.

Animals trample the ground reducing it to dust.

Animals die and can’t breed.

What are the effects of desertification?

Starvation

Food and water

shortages lead to

malnutrition, famine,

disease and high death

rates.

Aid Programmes

Large numbers of

people become

dependent on food

aid programmes.

Migration

From rural to urban

areas causing over-

population in towns.

To refugee camps.

Solutions?

How can we solve the problems

of desertification?

Solutions

In the short-term, provide food aid and water supplies to prevent suffering.

Improve water supplies by building large reservoirs and drilling deeper wells.

Conserve water in local small-scale schemes

Solutions con’t

Encourage sustainable farming practices (using locally-made tools, not tractors).

Provide drought-resistant seed such as millet (northern Nigeria). GM crops.

Tree planting schemes to reduce soil erosion (Mauritania).

International action to reduce the causes of global warming.

Solving the Problems: the resultsNov 1992

Nov 1998

Before and after

animals have

overgrazed and

trampled the

savanna.

http://managingwholes.com/kachana1.htm




Solving the Problems: the results

Before

After

Which scheme do you

think solved these

problems?

http://www.ecoresults.org/success_date_creek.html




Problems?

Civil wars, as in Ethiopia

and Sudan prevent aid

reaching stricken areas and

cause mass migration to

refugee camps.

Population growth

continues to outstrip food

supplies.

unit 3 ecosystems - wvhs.k12.nf.ca · unit 3 ecosystems geog 3202 ... the tertiary consumers would...

Documents