Transcript Unit II

Unit II
Ecology
• Ecology is the scientific study of
interactions among organisms and
between organisms and their environment
• To understand the relationships within the
biosphere, we have to ask questions that
range from an individual to the entire
biosphere
Levels of Organization
• Species – a group of organisms similar to one another
that breed and produce fertile offspring
• Population – groups of individuals that belong to the
same species in the same area
• Communities – assemblages of different populations of
different species that live together in a defined area
• Ecosystem – collection of organisms that live together
in a particular place, together with the physical
environment
• Biome – a group of ecosystems that have similar climate
and similar dominant communities
Levels Within Levels
• An ecosystem is a collection of all the organisms that live
in a particular place, together with their nonliving, or
physical, environment. Within an ecosystem, there are
several levels of organization. Your school and its
grounds are similar to an ecosystem.
1. What living things are found in and around your school?
2. What nonliving things are found in your school?
3. Into what large groups are the students in your school
divided?
4. Into what smaller groups are these large groups divided?
5. Are these groups ever divided into even smaller groups?
If so, what are these groups?
Earths Biosphere
•
The Biosphere spans from 8km above the
earth’s surface to 11km below the ocean’s
surface
• In addition to the biotic portion (i.e. populations
of organisms) the biosphere is made up of
three (3) major divisions of abiotic environment.
1. Lithosphere: the soil and rock or earth’s crust
2. Atmosphere: the gases surrounding the earth
3. Hydrosphere: all of earth’’s water, whether
gaseous, liquid or solid
•
Note: Biotic refers to living and abiotic refers to non-living
• The earth is considered a closed system, a
system in which nothing enters or leaves
– Apart from energy from the sun
• Of all the light energy that strikes the Earth’s
surface, only 0.06% is used by producers to
convert into chemical energy through
photosynthesis
• That 0.06% is enough energy to create 170
billion tons of new organic matter per year!
Energy Flow
• Sunlight is the primary source of energy for life
on earth; some organisms however are able to
use energy stored in inorganic chemical
compounds
– Ex. the fresh minerals spewed from deep undersea
geysers sustain life where light does not exist
• An organism that produces its own food from
sunlight are called autotrophs; because they
make their own food the common name for
these organisms is producers
– Photoautotroph = energy from the sun
– Chemoautotroph = energy from inorganic chemicals
• Photosynthesis is the process by which
light energy is used to power chemical
reactions that convert carbon dioxide and
water into oxygen and energy rich
carbohydrates
• General equation:
– CO2 + H2O + light energy carbohydrate + O2
• when chemical energy is used by
chemosynthetic organisms instead of light, it
follows a similar equation.
• Organisms that rely on consuming other
organisms are called heterotrophs; the
common name is consumers
– Herbivore: organisms that eat only producers
– Carnivores: organisms that eat only other consumers
– Omnivores: organism that eat both producers and
consumers
• Energy flows in one direction only, from the sun
or inorganic compounds to the autotrophs and
then through various heterotrophs
• Food chain: a series of steps in which energy is
transferred from producer through various levels
of consumers by eating or being eaten
• Food Web: in most ecosystems, feeding
relationships are not so simple; some producers
are consumed by more than one organism, and
that organism in turn takes part in many different
food chains. A food web links all the food chains
in an ecosystem together
• Each step in the food chain is called a
trophic level
– Producers are always the first trophic level
Ecological pyramids
• A pyramid has wide base that get progressively
narrower as it approaches its vertex
• An ecological pyramid is a diagram that shows
the relative amounts of energy or matter
contained within each trophic level
• Pyramid of Energy: describes the relative
amount of chemical energy at each trophic level
– 10% rule: only about 10% of the energy at each
trophic level moves on to the next level
• Question: Where does the other 90% go?
• Answer: organisms use that energy during life processes
such as locomotion, respiration and reproduction
• Biomass Pyramid: represents the total amount
of living tissue within a given trophic level; it also
represents the amount of potential food
available at each level
– Usually expressed in terms of grams organic matter
per unit area
• Pyramid of Numbers: based on the actual
number of individual organisms at each trophic
level
– This can easily differ from the other pyramids, as in a
forest ecosystem, a single tree may sustain a
multitude of other organisms which consume it
Energy Pyramid
Shows the relative amount of
energy available at each trophic
level. Organisms use about 10
percent of this
energy for
life processes.
The rest is lost
as heat.
Biomass Pyramid
Represents the amount of
living organic matter at each
trophic level. Typically, the
greatest biomass is at the
base of the pyramid.
Pyramid of Numbers
Shows the relative
number of individual
organisms at each
trophic level.
It’s Raining, It’s Pouring
•
1.
2.
3.
4.
How many times have you had to change your plans because of
rain? It probably didn’t help if someone tried to cheer you up by
saying, “But we really need the rain.”
However, rain is important. If it didn’t rain, how would living things
on land get water?
When rain falls on the ground, it either soaks into the soil or runs
across the surface of the soil. When rainwater runs across the land,
what body of water might collect the rain?
From here, where might the water flow?
After the rain, the sun comes out and the land dries. Where does
the water that had been on the land go?
Construct a diagram that would illustrate all the places a molecule of
water might go. Begin with a raindrop and end with a cloud.
Recycling in the Biosphere
• Unlike the unidirectional flow of energy in the
biosphere, all matter is recycled within and
between ecosystem through biogeochemical
cycles; these cycles include:
1. Water Cycle
2. Carbon Cycle
3. Nitrogen Cycle
4. Phosphorous cycle
•
Question: Why are these cycles important for life?
•
Answer: recall Unit 2, four major groups of organic compounds
include carbon, hydrogen, oxygen, nitrogen and phosphorous
Water cycle
• The process where surface water enters the
atmosphere is called evaporation; water can
also enter the atmosphere through the leaves of
plants through a similar process called
transpiration
• As the warm air rises it begins to cool,
condensation is when the water vapor begins
to coalesce into tiny droplets that form clouds
• When these droplets reach a critical size the
become precipitation and rain down to earth
• After falling to earth, water enters many different
systems, and flows from one system into
another; a few of these systems include:
– Ground water: the water seeps underground and
accumulates into vast reservoirs in porous rock
underground
– Running water: it may enter a stream or lake that
eventually enters a large body such as an inland sea
or ocean
– Plants: enters through roots and cycle begins again
• DYK: about 1/3 of all precipitation on land is lost
to the ocean through runoff?
Condensation
Precipitation
Evaporation
Transpiration
Runoff
Seepage
Root
Uptake
Nutrient Cycle #1
Carbon Cycle
• Carbon is a naturally occurring element on earth
• 4 processes move carbon around in the biosphere
1. Biological processes: such as photosynthesis,
respiration and decomposition, take up and release
carbon and oxygen
2. Geochemical processes: such as erosion and volcanic
activity may release carbon into the atmosphere
3. Mixed biogeochemical processes: the burial of
ancient organisms, and their conversion into fossil fuels
deep underground
4. Human Activities: mining, cutting, burning forests and
fossil fuels
• Video #2
CO2 in
Atmosphere
CO2 in Ocean
• What are the main sources of CO2 in the earth’s oceans?
Nutrient Cycle #2
Nitrogen Cycle
• All organisms require nitrogen to make amino acids and
nucleotides.
• Nitrogen makes up ~78% of the Earth’s atmosphere
• Nitrogen is brought into the soil through natural
processes (lightning) or biological processes (nitrogenfixing bacteria) in the form of ammonia Video #1
• Ammonia (NH3) is toxic, so nitrifying bacteria living in the
soil convert it into the less toxic form of nitrate (NO3)
• De-nitrifying bacteria destroy both of these types of
nitrogen compounds, sending it back into the air (this
prevents a toxic buildup in the ground)
• Nitrates are taken up by plants and enter the food chain
in the form of proteins and nucleic acids
• Video #2
• Nitrogen is naturally fixed by rhizobium bacteria that
live in symbiosis with the root systems of plants; plants
supply the carbohydrates, bacteria provide the nitrogen,
it’s win-win for both organisms involved! Video #3
• Nitrogen is the key component of artificial fertilizer
• Nitrogen is a limiting nutrient in agricultural systems,
the more nitrogen you can put in, the greater your return
– Limiting nutrients limit the growth and development of the
organisms in the region
• Soil erosion carries this fertilizer off farmers fields and
into wild ecosystems, where it violently upsets the
balance of these ecosystems creating “dead zones”, and
also entering the human water supply
Nutrient Cycle #3
Phosphorous Cycle
• Video #1; Dead Zone #2
• Phosphorous Cycle is a sedimentary cycle, meaning
the atmosphere does not play a significant role in this
cycle
• Phosphorous as a mineral enters the ecosystem through
erosion, the process whereby weathered rock is
transported via water
• This mineral enters living systems through plants, and
works its way through the trophic levels, finally ending up
back in the soil through death or waste produced
• This nutrient plays a huge role in stimulating algae
growth in lakes and coastal regions, which eliminates
oxygen, choking out all other life forms creating a “dead
zone”
Recall
• The key elements of Life have a direct
relation to these cycles:
• C
– Carbon Cycle
• H & O – Water Cycle
• N
– Nitrogen Cycle
• P
– Phosphorous cycle
• Video
Nutrient Limitation
• Ecologists study the
primary productivity of an
ecosystem, the rate at which
organic matter is created by
producers
• If one or more of the
nutrients necessary for life is
in short supply, it will limit
the growth and reproduction
of an organism
• When an ecosystem’s
growth is limited by a the
scarcity of a nutrient we call
it a limiting nutrient
• Question: What may be the limiting nutrient
in the desert?
• Answer: Water!
• Question: What are the major limiting
nutrients to growing plants in
Saskatchewan? How do we overcome these
limits?
• Answer: Nitrogen, Phosphorous and Potassium;
we overcome these limits by supplementing the
existing nutrients of the soil with fertilizers
containing additional nutrients.
In-Class Assignment
• On a new piece of loose-leaf paper from
your binder, complete the activity “Farming
in the Rye” on p.79 of your textbook.
• Complete the 4 problems listed and handin by the end of class.
Chapter 3 Assignment
• Complete Chapter 3-x assessment
questions:
• 3-1 #2, 3
• 3-2 #1-5
– Also: Focus on the Big Idea–Interdependence in nature
• 3-3 #1-6
Ecosystems and Communities
• Weather is the day to day condition of
Earth’s atmosphere at a particular time
and place
– Describe the weather today
• Climate refers to the average, year-afteryear conditions of temperature and
precipitation in a particular region
– Describe the Climate of Regina
• Question: Why is it that some planets
surface temperature varies by 500
degrees or more depending on day or
night, but Earth doesn’t?
• Answer: Our atmosphere regulates
surface temperature through the
Greenhouse Effect
Sunlight
Some heat
escapes
into space
Greenhouse
gases trap
some heat
Atmosphere
Earth’s surface
• Quickly sketch a diagram of the Greenhouse
effect in your notebook
•Question: Does your proximity to the equator
affect the amount of sunlight you receive?
• Answer: Yes, the
closer you are to
the equator, the
greater the
intensity of light;
the further you
are from the
equator the
greater the angle
of incidence
(more spread
out), which
results in
receiving less
light energy
Different Latitudes
90°N North Pole
Sunlight
Arctic circle
Sunlight
66.5°N
Tropic of Cancer
Equator
23.5°N
0°
Tropic of Capricorn 23.5°S
Sunlight
Arctic circle
Sunlight
66.5°S
90°S South Pole
What shapes an ecosystem?
• An ecosystem is characterized by its
characteristic biotic and abiotic factors
– List 3 examples each for possible biotic and abiotic
characteristics of a Pond ecosystem
• These factors determine the survival and growth
of an organism and the productivity of the
ecosystem in which that organism lives
• The area where an organism lives is called a
habitat
• If a habitat is an organisms home address, then
a niche is its occupation
• A niche is the full range of physical and
biological conditions in which an organism lives
and the way in which that organisms uses those
conditions
• Question: What are some of these
conditions?
• Answer: temperature and moisture
requirements, the food it eats, how it obtains
food, which other organisms consume the for
food, where it lives
“Fitting In”
• Organisms not only live together in ecological
communities, but they also constantly interact
with one another. These interactions, which
include predation and competition, help shape
the ecosystem in which they live.
1. Based on your own experiences, define
predation. Give one example of predation.
2. Based on your own experiences, define
competition. Give one example of competition.
Ecological Interactions
1. Competition: occurs when an organism of the
same or a different species attempt to use a
resource in the same place at the same time
–
•
Resource – any necessity for life, water, nutrients,
light, food or space
The competitive exclusion principle states
that no two species can occupy the same
niche in the same habitat at the same time;
one species will be forced to emigrate or go
extinct
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Spruce tree
Yellow-Rumped Warbler
Feeds in the lower part of the tree and
at the bases of the middle branches
2. Predation: where one organism feeds on
another, killing it in the process
3. Symbiosis: any relationship whereby two
species live closely together; further split into
three main categories
A. Mutualism: both species benefit from the
interaction
B. Commensalism: one species is helped, the other is
indifferent
C. Parasitism: one organism lives on or inside another
organism, harming the other organism in the
process
Ecological Succession
• Ecosystems are constantly changing in
response to natural and human
disturbances. As an ecosystem changes,
its older inhabitants die out and new
organisms move in, causing further
changes to the community
• The series of predictable changes that
occurs in response to these disturbances
is called ecological succession
• Primary Succession occurs where no soil
exists; typically occurs after a devastating
change, such as a volcanic eruption or a bare
rock beneath a quickly receding glacier
• After an island is built through geological
processes, primary succession includes a
pioneer species, the first species to populate
the area.
• Lichens are typically a pioneer species; they are
composed of an algae and a fungus living as
mutualistic symbiotes, and can grow on and
break down bare rock into soil
• Secondary Succession follows a less significant
disturbance, that typically leaves the soil intact such as a
forest fire or farming
• Nearby community interactions tend to restore the
ecosystem to original conditions
• it was only recently discovered that forest fires play a
vital role in maintaining the health of ecosystems, by
eliminating older and diseased trees and activating many
seeds on the forest floor
• Prescribed burns are now performed in parks across
Canada as a means to maintain the health of the forest.
• Some human disturbances will permanently eliminate
members of an ecosystem and alter it forever to a point
where it may not recover.
• Succession in marine Systems varies enough to get its
own category; we will refer to this as a whale-fall
community
• On the seafloor there is no light, but still organisms exist
with the express purpose of decomposition and returning
the nutrients into the upper ecosystem
• Should a large body (such as a whale) fall to the ocean
floor:
1. Scavengers such as hagfish and sharks will consume the flesh of
the organism
2. Once picked clean, the carcass can no longer support a large
community; however the surrounding sediment is enriched with
nutrients that support a variety of worms and other organisms
3. Chemosynthetic bacteria will consume the skeletal remains, who in
turn are the producers for a food chain that includes mussels, snails
and crabs.
Assignment
• Biology Worksheet:
– Examining the Stages in Ecological
Succession
• Receive Worksheet; complete using
remaining class period
• Due Date: 2 Class days hence
Biomes
• Complete the online activity:
– Active Art Assessment: BIOMES
• The web link can be found on p.99 of your text
• When finished, use the remainder of the
period to complete the attached
Crossword: “Communities and Biomes”
Assignment
• Create a Chart in your notebook that includes the
following headings:
–
–
–
–
–
–
–
Name of Biome
Temperature
Precipitation
Soil Type
Dominant Plants
Dominant Animals
Other Notable Characteristics
• Read 4-3 and 4-4 pp.98-105 and fill in the chart as
described above
– Hints: turn your page widthwise for the table; leave yourself
plenty of space for your answers; the table may stretch onto a
second page
Assignment
• Complete the Activity
“Analyzing Data: Ecosystem Productivity”
on p.111 on a separate piece of paper
• Complete questions 1-4
• Due Date: 1 class day hence
Chapter 4 Assignment
• Read through Chapter 4 and complete the
following questions from the section
Assessments
• 4-1 #1-4
• 4-2 #1-5 including “Writing in Science”
• 4-3 #2-6 including “Focus on the Big Idea”
• 4-4 #1-5 including “Writing in Science”
• The underlined portions of this assignment
should be completed with care and attention to
detail, as they will be evaluated for quality at the
conclusion of this Unit
Unit 2 – Part 1
• We are going to split our Ecology Unit into
two parts; we will assign a review and
write an exam for this Unit that will
correspond to Chapters 3 and 4 in your
textbook
• Chapter 3 Review:
• Read Study Guide (p.82) and complete
the following problems from the following
Chapter Review:
• #1-10, 26-30
• Chapter 4 Review
• Read Study Guide (p.114) and complete
the following problems from the following
Chapter Review:
• #1-10, 26, 27, 29-33
Populations
• Complete the Inquiry Activity “How Populations Grow?”
from p.118 in your text
• each What is the rate of growth year?
– Pairs of rabbits (÷2)
– Each pair makes six bunnies (x6)
– Net increase: each generation of rabbit increases by a factor of 3
(triples)
• When graphing your data, use the entire y-axis, each
square equals 10 rabbits.
• Label your graph appropriately (title, label for each axis,
etc.)
• Complete Question #1-3
1st
Year
# rabbits 6
2nd
3rd
4th
18
…
…
# Rabbits
y = 0.6667e1.0986x
R2 = 1
180
160
# of Offspring
140
120
100
80
60
40
20
0
0
1
2
3
Years
4
5
6
# Rabbits - 10 years
45000
40000
35000
# Offspring
30000
25000
20000
15000
10000
5000
0
0
2
4
6
Years
8
10
12
# Rabbits - 20 years
2500000000
# Offspring
2000000000
1500000000
1000000000
500000000
0
0
5
10
15
Years
20
25
Activity Review
• Question: Once the original pair of
rabbits began multiplying, what would
happen to the plant populations?
• Answer: they would decrease at equal rates
• Question: If rabbits began to die off,
what would happen to plant
populations?
• Answer: they would begin to increase, as there
would be fewer rabbits around to eat them.
Biotic Potential
• The size a population would reach given
unlimited resources and space
• The factors that prevent this “ideal growth”
are called limiting factors
• List some potential limiting factors:
•
FYI: [Use text to discover the answers to the following questions. These
answers are your “notes” for this section.]  no need to copy this note
• Question: What are the three most
important characteristics of a
population
• Answer: Geographic distribution, density &
growth rate
• What 3 factors affect population size?
• Answer: Number of deaths, number of births,
number of individuals entering or leaving the
population
• Question: What is the difference between
exponential and logistic growth?
• Answer: exponential growth occurs when a population
grows at a constant rate; occurs with unlimited space
and food, with the absence of disease and predators).
Logistic growth occurs when population growth slows or
stops completely after a period of exponential growth.
• Question: What is carrying capacity?
• Answer: when population growth equals zero (logistic
growth); this represents equilibrium, when a population
is in balance with its environment. (births=deaths)
Making Connections
• Population Density can be described
mathematically:
Population Density = # of Individuals
Area
• Question: Suppose there are 150
bullfrogs living in a pond that covers an
area of 3 km2. What is the density of the
bullfrog population?
• Answer: 150bullfrogs / 3km2 = 50 bullfrogs/km2
In-Class Assignment
• Complete “Analyzing Data” on p. 123.
– Graph paper is available
– Answer questions #1-4
• When complete, staple or paperclip your
assignment together and hand in
• Complete “Thinking Visually”, create a
concept map of all terms in your notebook
Fruit Fliy Population
350
300
# Fruit Flies
250
200
150
100
50
0
0
5
10
15
20
25
Days
30
35
40
45
Rabbit Population
18000
R2 = 0.9349
16000
14000
# of Rabbits
12000
10000
8000
6000
4000
2000
0
0
20
40
60
Generations
80
100
120
Limits to Growth
• Question: Look at Fig. 5-5 (p.124); how might
each of these factors increase the death rate
of a population?
• Possible Answers Include:
– Competition= lesser fit individuals are unable to get resources
they need to survive
– Predation= individuals are consumed
– Parasitism & Disease= individuals become less fit/dead as a
result of infection; this prevents them from consuming necessary
resources
– Drought, etc.= access to resources (water, food) limited,
individuals starve to death
– Human Disturbances= access to space, food, clean water
becomes restricted; toxins introduced to environment
• Wolf and Moose Populations on Isle Royale
– Describe the relationship you observe between populations
• Question: What is the difference between densitydependent and density-independent factors?
• Answer:
Competition, predation and parasitism/disease are all natural
components to ecosystems, members of that biome. These are
natural mechanisms within the biome to control populations and as a
result they are density-dependent.
• Unusual weather and human interference are examples of density
independent factors. They can occur at any time and serve no
natural purpose for the health of the Biome.
Human Population Growth
Industrial
Revolution
Agriculture
Begins
Bubonic
Plague
Plowing and
irrigation
Question: if you extended this graph hundreds of years
into the future, what would it look like?
• Like populations of many other living organisms,
the size of the human population tends to
increase with time.
• Question: How did the human population
manage to increase as much as it did?
• Answer:
– advances in medicine decreased death rate, and fewer infant
mortalities increased the birth rate
– The availability of food and water supported larger families
• A demographic transition is a dramatic shift in
birth and death rates.
• With advances in medicine, nutrition, education
and sanitation, more children survive to
adulthood, and more adults live to a old-age
• When death rates fall, birth rates typically remain
the same, and as a result our population grows
• Did you know: Our generation will be the first in human history to
have a lower life expectancy than our parents generation since the
bubonic plague? What “plague” are we experiencing now?
U.S. Population
Males
Females
Rwandan Population
Males
Females
Question: How do the United States and Rwanda differ in the percentages of
10-14 year olds in their population?
Answer: The united states is about 6%, and in Rwanda about 14%.
• Question: What factors might influence why
populations in different countries grow at
different rates?
• Answer: birth rates, death rates and age structure of
population.
• Describe the demographic transition and
explain how it might affect a countries
population
• Answer: When it begins, both birth and death rates are
high. As death rates fall due to advances in medicine,
nutrition, etc the birthrate will remain high. The
population will adapt to this and eventually the
population will level out as birth rate slows and even
stops.
• Why do age structure diagrams help
predict future population trends?
– Example: In Canada, we have a very large elderly
population, what can you predict about birth and
death rates in the near future? Do the elderly give
birth? Are they at greater risk of death than others?
• Answer: Diagrams include data on younger
individuals in age groups that will contribute to
population growth as members of those groups
mature.
Chapter 5 - Review
• Read and complete the following
sections/questions from Chapter 5
• 5-1 #3-5
• 5-2 #1-5
• 5-3 #1, 2, 4, 5
Humans in the Biosphere
•
Watch Video Justicia Now
–
•
Questions to follow video
Copy and complete the following questions in your
notebook:
1. What impact did oil exploration and exploitation have
on the environment and surrounding indigenous
communities?
2. What are 3 things you learned from this video?
3. Why do you think the companies involved get away
with these crimes? Does this happen in Canada?
Explain how it should be dealt with in Canada.
1
2
3
6-1: A Changing Landscape
• While reading this section, create a 2
column Chart like the following
Types of human Impact
activities
Ex. Hunting and
Gathering
Ex. Caused major mass
extinction of species
such as mammoths and
Giant Sloths
Question:
• What are some of the disadvantages of
relying on hunting and gathering for your
food?
• Answer: You may have to move your home to follow the
animals that sustain you; without being cared for by
humans, some beneficial plants may die due to drought
or competition with other plants.
Question:
• What are some advantages to using
agricultural machines such as tractors and
combines?
• Answer: vast acreages can be plowed, sown, and
harvested in less time and with fewer people, enabling
farmers to produce crops on a large scale
• Are there any disadvantages?
• Answer: Initial cost? Repairs and maintenance?
Increased consumption of energy, exhaust gases
released to environment, noise, etc.
Exam Question from this Section:
• Fill in the chart below:
Type of Human Activity
Hunting & Gathering
Agriculture
Green Revolution
Impact on the
Environment
Question:
• Cities and Suburbs can grow out of
control, and be so sprawled out that we
run into problems. What are these
problems and how can they be prevented?
• Answer:
– Wastes  reduce – reuse – recycle!
– Put a cap on how big a city should be able to grow
outwards (daily commutes in cities like Toronto and
Calgary are atrocious!)
– Other ideas?
Historical footnote
• Norman Borlaug was born on a farm. After Receiving his
doctorate in Plant Pathology from university, he became
director of a program in Mexico that focused on breeding
new and improved crops
• In the years that followed, The International Maize and
Wheat Center near Mexico City, Norman was successful
at creating new strains/breeds of wheat and corn that
were able to withstand disease and drought with
relatively high yields (yield is how much grain you get
from a given area)
• By the 1960’s his strains were being planted throughout
the world, especially in famine wracked nations such as
India and Pakistan. He received the Nobel Peace Prize
for his work.
Question
• How has an understanding of Biology helped
mankind?
• Potential Answers: creating new crops that can survive
harsh climates, enriching crops with vitamins to prevent
blindness… others?
• Does this area of study still occur today?
• Answer: Yes! For example University or Saskatchewan
created a strain of rapeseed nearly 50 years ago and
called canola, this is big business! U of S is the premier
university in the world for agricultural research, a very
profitable science that benefits the world
Assignment
• Read 6.1 from your text
• Answer Questions #3, 5 on p. 143
6-2: Renewable and NonRenewable Resources
• {Read aloud introduction}
• Question: What is the tragedy of the commons?
Trading forests for food…
• During the past 200 years, our neighbours to the south
(USA) have had their forest lands reduced by about
20%; This amounts to an area roughly the size of
Texas
• Worldwide, forests have been reduced in size by 20%
in the last 30 years; much of this has been cleared in
order to grow crops
• The impact of reducing forest cover can include: more
severe destruction from natural disasters (forests
prevent floods and absorb force from hurricanes and
tsunami), a reduction in biodiversity, less rain and
increased CO2 in our atmosphere
Fisheries
• World fisheries are regions where fish are harvested
industrially
• In 2000, the world catch was almost 95 million
metric tons. 86 million came from our oceans.
• World aquaculture amounted to nearly 36 million
tons
• The top 3 types of fish were: sardine, herring &
anchovies at about 25 million metric tons
• The leading countries who fish are: China, Peru,
Japan, India, USA, Indonesia, Chile and Russia
• Pacific Ocean fisheries account for about ½ the
worlds fish catch
Questions
• How does Biological pest control
contribute to sustainable development?
• Answer: It does not create pollution that can
enter the food chain and harm other organisms
Question
• What are two ways in which
reforestation might affect the
biosphere?
• Answer: It would prevent further soil
erosion (which creates relatively lifeless
deserts) and would reduce global
atmosperic CO2 (greenhouse gas)
Question
• Describe the History of the Cod population
in Georges Bank between 1980 and 2000.
• Answer: in 1980 there were ~80,000 tons of cod. That
total dropped until the late 80’s when stocks rebounded
somewhat. In the early 90’s stocks dropped significantly,
only to begin a slow rise.
• By 2000, the amount of fish was less than 1/3 the
amount present in 1980
Interactive Fisheries Activity!
(www.phschool.com ; cbp-2062 (p.147)
•
1.
2.
3.
4.
Copy out the following questions onto a separate piece
of paper in your notebook
Were you able to reach your target population by
changing any single parameter?
Which parameter did you change that got you closest
to your goal?
Is it possible to improve the spawning stock biomass
by setting only one kind of limitation on the fishing
industry?
Once the spawning stock biomass has reached its
goal do you think that limitations should still be put on
the fishing industry in future years?
Question
• What pathways do the chemicals in the
atmospheric emissions take on their
way to becoming acid rain?
(figure 6-12)
• Answer: The gases combine with water
vapor to form drops of nitric acid and
sulfuric acid, which can drift long distances
before they fall to the ground as rain.
Assignment
• Read Section 6-2
– Complete problems #1, 2, 3, 5 (p.149)
6-3: Biodiversity
•
Predict the definitions of the following
terms using the underlined term in each.
1. Habitat fragmentation
2. Invasive species
3. Biological magnification
Question
• How is the illustration of DDT
concentration the opposite the pyramid of
numbers to the left in fig. 6-16 (p. 152)?
• Answer: It’s like an upside down pyramid; the
concentration of pollution is very small at the
bottom, and gets bigger as it moves up
• By What number is the concentration of
DDT multiplied by at each successive
trophic level?
• Answer: 10
Historical Footnote
• DDT (dichlorodiphenyltrichloroethane) was first
synthesized chemically in the lab during the
1930’s
• It was used during WWII to kill the lice and ticks
that carried the disease typhus, and later to kill
mosquitoes that carried the disease malaria
• DDT is exteremely effective at killing these
disease-carrying insects, however the problem
is that DDT is so stable it doesn’t degrade over
time or break down easily (like a twinkie!)
• To this day it persists in our ecosystems,
continuing to drive higher level consumers likes
hawks and eagles to extinction
• DYK  Most of last centuries DDT is trapped in
the polar ice caps? The accelerated melting of
these caps observed in the last decade has
resulted in the release of tons of DDT back into
ecosystems!
• Question: What is being released by melting
polar caps?
• Answer: DDT and other man-made chemicals, along
with CO2 trapped in the ice is being released which
creates a GHG feedback loop; dissolved elements and
minerals such as the toxin arsenic are also released
Tragedy in Minamata
• A tragic example of biomagnification involved mercury, a
byproduct of the production of batteries, fluorescent light
bulbs and mining to name a few.
• In humans, mercury affects the central nervous system
(brain and spine), causing paralysis, mental illness and
death.
• Many years ago, factories located around Minimata Bay
in Japan disposed of mercury into the ocean (many
people still consider it a big garbage can)
• this dissolved mercury was absorbed by phytoplankton
and passed up the food-chain; eventually it reached
dangerous concentration in larger fish such as Swordfish
and Tuna
• Because much of their diet included fish, local
Japanese populations ingested this mercury,
many became terribly ill and died, others had
physically deformed and mentally retarded
children
• This tragedy is an example of why careful
scientific study are needed before disposing of
waste in the environment
• Question: Why is it still recommended people
consume no more than 1 tin of Tuna per week?
• Answer: Tuna remain contaminated even after several
decades of proper disposal of mercury
Guided Reading
•
During your provided reading time, I will ask questions regarding
each heading. I will space my questions out ~ 3-5 min. Please
pause your reading when asked each question.
1. What is the value of biodiversity? (hint: fig. 6-14)
2. Why are habitat alterations a threat to
biodiversity? (see fig 6-15)
3. Why does pollution become more
concentrated as it moves through the food
chain?
4. Why are introduced species a threat to
biodiversity? (see fig 6-17)
Assignment
• Read 6-3
– Complete problems 1, 2, 3, 5, 6
How Much Should It Cost?
•
•
1.
2.
3.
4.
You may have read that when something becomes hard to obtain,
its price usually increases. Such is the case for materials like gold
and diamonds, which are nonrenewable resources. Using similar
thinking, some researchers believe that all the valuable services
provided by a healthy ecosystem should be assigned a dollar value.
Rank the following items in order of their importance to you. Then,
next to each item, write down how much you would be willing to pay
for it.
Fresh, clean drinking water
Clean air to breathe
An endangered plant containing a substance that can cure cancer
Gas for your family car
6-4: Charting a Course for the
Future
• Question:
What would happen to the temperature of the
atmosphere if the amount of greenhouse
gases increased?
• Answer: Like wearing a parka in the summer, the
atmosphere would become warmer – hence “Global
Warming”
• Question:
What action did nations take to deal with the
ozone hole?
• Answer: Many nation reduced, then finally banned the
production and use of CFC’s
Cover Crops
Legumes, grasses, and other
cover crops recycle soil nutrients,
reduce fertilizer need, and
prevent weed growth.
Contour Plowing
Contour plowing reduces
soil erosion from land runoff.
On hilly areas, plowing is done
across the hill rather than
straight up and down.
Controlled Grazing
By managing graze periods and herd
densities, farmers can improve nutrient
cycling, increase the effectiveness of
precipitation, and increase the carrying
capacity of pastures.
A
B
Yr. 1
Yr. 3
C
Crop Rotation
Different crops use and
replenish different nutrients.
alfalfa By rotating crops, the loss
corn alfalfa (plowed in) of important plant nutrients
is decreased.
corn
Yr. 2
Biological Pest Control
The use of predators and parasites
to control destructive insects
minimizes pesticide use as well as
crop damage
oats alfalfa
Ecosystem Services
Solar energy
Production of oxygen
Storage and recycling of
nutrients
Regulation of climate
Purification of water and air
Storage and distribution of
fresh water
Food production
Nursery habits for wildlife
Detoxification of human and
industrial waste
Natural pest and disease
control
Management of soil erosion
and runoff
In-Class Assignment
– Complete “Analyzing Data” (p.158) on a piece
of paper separate from your notes. Hand-in
by the end of class. This is NOT a group
activity.
Assignment
• Read 6-4
– Complete Problems (p.160) # 1, 2, 3
End of Ecology Unit
• Important Dates:
– Open-book ecology exam: Thursday April 9th
– Closed-book Midterm Exam: Friday April 24th
• The unit of Study to follow focuses on
Evolution and the Classification of Life
Ecology Review
• Ch. 5 – Populations
– Complete Assessment Problems on p. 135
– #1-10, 24, 25, 27-32
• Review Problems
• Ch. 6 – Human Impact on the Biosphere
– Complete Assessment Problems on p.163
– #1-11, 22, 24, 25, 29-31
• Review Problems