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

• • • 1.

2.

3.

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.

Lithosphere: the soil and rock or earth’s crust Atmosphere : the gases surrounding the earth 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 these organisms is

autotrophs producers

; because they make their own food the common name for – 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: – CO 2 + H 2 O +

light energy

 carbohydrate + O 2 • 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:

amount of chemical energy at each trophic level –

10% rule:

describes the relative 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

per unit area : 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

Pyramid of Numbers

level : based on the actual number of individual organisms at each trophic – 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

• 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?

1. 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?

2. From here, where might the water flow?

3. After the rain, the sun comes out and the land dries. Where does the water that had been on the land go?

4. 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

carbon and oxygen : such as photosynthesis, respiration and decomposition, take up and release

2. Geochemical processes

: such as erosion and volcanic activity may release carbon into the atmosphere

3. Mixed biogeochemical processes

deep underground : the burial of ancient organisms, and their conversion into fossil fuels •

4. Human Activities

: mining, cutting, burning forests and fossil fuels Video #2

CO 2 in Atmosphere CO 2 in Ocean

•

What are the main sources of CO 2 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 (nitrogen fixing bacteria) in the form of ammonia Video #1 • • Ammonia (NH 3 ) is toxic, so nitrifying bacteria living in the soil convert it into the less toxic form of nitrate (NO 3 ) 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 • Nitrogen is a organisms in the region

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! • Nitrogen is the key component of artificial fertilizer

limiting nutrient

Video #3 in agricultural systems, the more nitrogen you can put in, the greater your return – Limiting nutrients limit the growth and development of the • 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

cycle

; Dead Zone #2

• Phosphorous Cycle is a

erosion

transported via water

sedimentary cycle

, meaning the atmosphere does not play a significant role in this • Phosphorous as a mineral enters the ecosystem through , the process whereby weathered rock is • 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 • H & O – Carbon Cycle – Water Cycle • • N • P

Video

– Nitrogen Cycle – Phosphorous cycle

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 hand in 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-after year 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

Sunlight Sunlight Sunlight

Different Latitudes 90 °N North Pole 66.5

°N Arctic circle

Sunlight

Tropic of Cancer Equator Arctic circle 66.5

°S 90 °S South Pole 23.5

°N 0 ° Tropic of Capricorn 23.5

°S

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

Bay-Breasted Warbler

Feeds in the middle part of the tree Spruce tree

Cape May Warbler

Feeds at the tips of branches near the top of the 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

disturbance, that typically leaves the soil intact such as a forest fire or farming follows a less significant • 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

Year 1 # rabbits 6 st 2 nd 18

# Rabbits

3 rd … y = 0.6667e

1.0986x

R 2 = 1 180 160 140 120 100 80 60 40 20 0 0 1 2 3

Years

4 5 6 4 th …

# Rabbits - 10 years

45000 40000 35000 30000 25000 20000 15000 10000 5000 0 0 2 4 6

Years

8 10 12

# Rabbits - 20 years

2500000000 2000000000 1500000000 1000000000 500000000 0 0 5 10

Years

15 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 km 2 . What is the density of the bullfrog population?

Answer: 150bullfrogs / 3km 2 = 50 bullfrogs/km 2

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 350 300 250 200 150 100 50 0 0 5 10 15 20

Days

25 30 35 40 45

18000 16000 14000 12000 10000 8000 6000 4000 2000 0 0

Rabbit Population

R 2 = 0.9349

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 density dependent 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

Agriculture Begins Bubonic Plague Industrial Revolution 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 activities

Ex. Hunting and Gathering

Impact

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 Impact on the Environment Hunting & Gathering Agriculture Green Revolution

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 Non Renewable 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 CO 2 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 CO 2 (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

• 1.

2.

3.

4.

Interactive Fisheries Activity!

( www.phschool.com

; cbp-2062 (p.147) 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 CO 2 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?

• • 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.

1. Fresh, clean drinking water 2. Clean air to breathe 3. An endangered plant containing a substance that can cure cancer 4. 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

Biological Pest Control

The use of predators and parasites to control destructive insects minimizes pesticide use as well as crop damage C Yr. 1 Yr. 2 corn corn oats alfalfa alfalfa

Crop Rotation

Different crops use and replenish different nutrients. alfalfa (plowed in) By rotating crops, the loss of important plant nutrients is decreased.

Yr. 3

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 9 th – Closed-book Midterm Exam: Friday April 24 th • 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